Ophthalmology – Systemic Lupus Erythematosus

What the Disease Represents

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease characterized by:

• Autoantibody production
• Immune-complex formation
• Complement activation
• Inflammation and vascular injury

The disease typically follows a:

Relapsing-remitting course

and may affect:

• Skin
• Joints
• Kidneys
• Hematologic system
• Nervous system
• Cardiovascular system
• Eyes

Ocular manifestations may sometimes reflect:

Active or severe systemic lupus.

Why SLE Matters to Ophthalmologists

Almost any ocular structure can be affected.

Important manifestations include:

• Keratoconjunctivitis sicca
• Eyelid discoid lupus lesions
• Episcleritis
• Scleritis
• Peripheral ulcerative keratitis
• Uveitis
• Retinal microangiopathy
• Severe vaso-occlusive retinopathy
• Choroidopathy
• Optic neuropathy
• Cranial neuropathies
• Hydroxychloroquine retinal toxicity

Among these, severe retinal vascular disease and optic nerve involvement are particularly important because they can cause:

Permanent visual loss.

Who Is Most Commonly Affected

SLE occurs predominantly in:

Women of reproductive age

with a female predominance of approximately:

9:1

Disease severity and prevalence vary among populations and are influenced by:

• Genetic susceptibility
• Hormonal factors
• Environmental triggers
• Socioeconomic and healthcare factors

How Autoimmunity Develops

SLE results from loss of tolerance to self-antigens.

Important mechanisms include:

• Abnormal clearance of apoptotic material
• B-cell activation
• Autoantibody production
• Immune-complex deposition
• Complement activation
• Type I interferon signaling
• T-cell dysregulation

Vascular injury may result from:

• Immune-complex vasculopathy
• Endothelial dysfunction
• Thrombosis

Genetic Susceptibility

SLE is polygenic rather than caused by a single gene.

Associations involve:

• HLA loci
• Complement pathways
• Interferon signaling
• B-cell regulation

Family members have increased risk, but inheritance is:

Not Mendelian.

Common Systemic Manifestations

Patients may have:

• Malar rash
• Photosensitivity
• Arthritis
• Oral ulcers
• Serositis
• Nephritis
• Cytopenias
• Neurologic disease
• Constitutional symptoms

Fatigue is particularly common.

Modern Classification Framework

Older teaching used the rule:

4 of 11 ACR criteria

This has largely been replaced for classification purposes by the:

2019 EULAR/ACR criteria

These require:

1. Positive ANA at least once as an entry criterion
2. Weighted clinical and immunologic features
3. A cumulative score of ≥10 points

Classification criteria support research and standardized case definition but do not replace:

Clinical diagnosis by the treating physician.

Important Lupus Autoantibodies

Common serologic markers include:

• ANA – highly sensitive but nonspecific
• Anti-dsDNA – relatively specific and often associated with nephritis/activity
• Anti-Sm – highly specific
• Anti-Ro/SSA
• Anti-La/SSB
• Antiphospholipid antibodies

Complement levels such as:

• C3
• C4

may fall during active disease.

Antiphospholipid Antibody Syndrome

SLE may coexist with:

Antiphospholipid syndrome (APS)

Relevant antibodies include:

• Lupus anticoagulant
• Anticardiolipin antibody
• Anti-β2-glycoprotein I antibody

APS increases risk of:

• Arterial thrombosis
• Venous thrombosis
• Retinal artery occlusion
• Retinal vein occlusion
• Cerebral ischemia

This is particularly important in patients with:

Severe vaso-occlusive retinal disease.

Common Eye Symptoms

Patients may report:

• Dryness
• Burning
• Foreign-body sensation
• Redness
• Photophobia
• Ocular pain
• Floaters
• Diplopia
• Blurred vision
• Sudden visual loss

Symptoms depend heavily on the structure involved.

Eyelid Manifestations

Discoid lupus erythematosus may affect the eyelids.

Findings can include:

• Scaly plaques
• Erythema
• Atrophy
• Dyspigmentation
• Madarosis
• Lid-margin distortion

It may resemble:

• Chronic blepharitis
• Seborrheic disease

Ocular Surface Disease

The most frequent ophthalmic problem is:

Dry eye disease

often related to:

• Lacrimal gland dysfunction
• Secondary Sjögren disease
• Meibomian gland dysfunction
• Medication effects

Corneal Findings

Dry eye may produce:

• Reduced tear meniscus
• Punctate epithelial keratitis
• Filamentary keratitis
• Fluctuating vision

Less commonly SLE may cause:

• Interstitial keratitis
• Peripheral ulcerative keratitis
• Corneal thinning

Peripheral Ulcerative Keratitis

PUK is an uncommon but potentially serious manifestation.

It may occur with:

• Scleritis
• Active systemic vasculitis

Findings include:

• Peripheral epithelial defect
• Stromal thinning
• Inflammatory infiltrate

This should prompt:

Urgent systemic evaluation and immunosuppressive treatment.

Episcleritis

Episcleritis generally causes:

• Sectoral superficial redness
• Mild discomfort
• Normal vision

Superficial episcleral vessels typically:

Blanch with phenylephrine.

It is usually less threatening than scleritis.

Scleritis

Scleritis may present with:

• Deep boring pain
• Violaceous redness
• Globe tenderness
• Possible visual decline

Deep vessels generally:

Do not blanch substantially with phenylephrine.

Scleritis in an SLE patient can indicate:

Significant systemic inflammatory activity.

Anterior Uveitis

Anterior uveitis is less common than ocular surface or retinal disease.

Possible findings include:

• Cells
• Flare
• Posterior synechiae

Severe hypopyon uveitis is unusual and should prompt consideration of:

• Infection
• Behçet disease
• Other inflammatory disorders

Lupus Retinopathy

The classic retinal manifestation is:

Lupus retinal microangiopathy

which reflects systemic vascular injury.

Common findings include:

• Cotton-wool spots
• Intraretinal hemorrhages
• Microaneurysms
• Hard exudates
• Vascular tortuosity

Cotton-wool spots represent:

Focal retinal nerve fiber layer ischemia.

Why Lupus Retinopathy Matters

Retinopathy often correlates with:

• Active systemic disease
• Renal disease
• CNS involvement
• Hypertension

Therefore retinal findings may serve as a marker of:

More severe systemic lupus activity.

Severe Vaso-Occlusive Retinopathy

A much more serious phenotype is:

Occlusive lupus retinal vasculopathy

which can produce:

• Extensive capillary nonperfusion
• Branch retinal artery occlusion
• Central retinal artery occlusion
• Branch retinal vein occlusion
• Central retinal vein occlusion
• Combined arterial and venous occlusion

Role of Antiphospholipid Antibodies

Severe thrombotic retinal vascular disease should raise suspicion for:

Antiphospholipid syndrome

especially when occlusion is:

• Extensive
• Bilateral
• Recurrent
• Occurring at a young age

Ischemic Retinal Complications

Extensive nonperfusion can lead to:

• Retinal neovascularization
• Neovascularization of the disc
• Vitreous hemorrhage
• Fibrovascular proliferation
• Tractional retinal detachment
• Neovascular glaucoma

These complications may threaten vision even after systemic inflammation is controlled.

Fluorescein Angiography

FA is particularly useful when retinal vascular disease is suspected.

It can demonstrate:

• Capillary nonperfusion
• Vascular leakage
• Retinal vasculitis
• Macular ischemia
• Neovascularization

Wide-field angiography can help quantify:

Peripheral retinal ischemia.

OCT

Macular OCT is useful for detecting:

• Macular edema
• Intraretinal fluid
• Subretinal fluid
• Ischemic retinal thinning
• Hydroxychloroquine toxicity

OCT is also important for following:

Structural response to treatment.

OCT Angiography

OCTA may demonstrate:

• Reduced capillary density
• Deep and superficial plexus abnormalities
• Foveal avascular zone enlargement

It can complement FA but cannot directly demonstrate:

Vascular leakage.

Lupus Choroidopathy

SLE may rarely produce:

Choroidal vascular dysfunction

with:

• Serous retinal detachment
• RPE detachments
• Choroidal ischemia
• RPE changes

It is often associated with:

• Severe systemic hypertension
• Lupus nephritis
• Active systemic disease

Why Choroidopathy Can Develop

Possible mechanisms include:

• Choroidal vasculitis
• Immune-complex deposition
• Choroidal ischemia
• Severe hypertension
• RPE dysfunction

These impair normal removal of:

Subretinal fluid.

Distinguishing Lupus Choroidopathy From CSC

This distinction can be challenging because SLE patients may receive corticosteroids, which can precipitate:

Central serous chorioretinopathy

Thus subretinal fluid in an SLE patient may reflect:

• Active lupus choroidopathy
• Steroid-associated CSC
• Hypertensive choroidopathy

The management differs substantially.

Optic Nerve Disease

Optic nerve involvement is uncommon but potentially severe.

Manifestations include:

• Optic neuritis
• Ischemic optic neuropathy
• Optic disc edema
• Optic nerve vasculitis
• Papilledema from raised intracranial pressure

Lupus Optic Neuropathy

Patients may develop:

• Sudden or subacute visual loss
• Dyschromatopsia
• RAPD
• Visual-field defects

Mechanisms may include:

• Inflammation
• Small-vessel ischemia
• Thrombosis

Severe optic neuropathy generally requires:

Urgent systemic treatment.

Neuro-Ophthalmic Manifestations

CNS lupus or associated vascular disease may cause:

• Cranial nerve palsies
• Internuclear ophthalmoplegia
• Homonymous visual-field defects
• Cortical visual loss
• Nystagmus
• Ocular motor abnormalities

When Neuroimaging Is Needed

MRI brain/orbits ± vascular imaging should be considered with:

• Optic neuropathy
• Cranial neuropathy
• Homonymous field loss
• Focal neurologic symptoms
• Suspected CNS vasculitis or thrombosis

Infection Must Always Be Considered

SLE patients are often receiving:

• Corticosteroids
• Antimetabolites
• Biologic agents
• Other immunosuppressive drugs

New ocular inflammation may therefore actually represent:

Infection rather than autoimmune flare.

Important infections include:

• HSV
• VZV
• CMV
• Toxoplasmosis
• Tuberculosis
• Syphilis

Escalating immunosuppression without considering infection can be dangerous.

Dry Eye Treatment

Ocular surface disease may be treated with:

• Preservative-free artificial tears
• Lubricating gel or ointment
• Treatment of meibomian gland dysfunction
• Topical cyclosporine
• Lifitegrast or another approved anti-inflammatory dry-eye therapy

Severe disease may require:

• Serum tears
• Punctal occlusion
• Scleral lenses

Treating Episcleritis

Mild disease may respond to:

• Lubrication
• Oral NSAIDs when necessary

Frequent recurrence should prompt assessment of:

Systemic disease activity.

Treating Scleritis and PUK

These usually require:

Systemic anti-inflammatory/immunosuppressive therapy

rather than topical drops alone.

Treatment may include:

• Systemic corticosteroids
• Steroid-sparing immunomodulators
• Biologic therapy according to systemic disease

Treating Lupus Retinal Vasculitis

Sight-threatening retinal inflammation generally requires:

Rapid systemic control of lupus activity

often using:

• High-dose systemic corticosteroids
• Additional immunosuppression

depending on severity.

Agents may include:

• Mycophenolate
• Cyclophosphamide
• Azathioprine
• Rituximab
• Other disease-directed therapies

Management should be coordinated with:

Rheumatology.

Managing Vaso-Occlusive Disease

If APS or another thrombotic mechanism is present, treatment may require:

Antithrombotic therapy

under systemic specialist supervision.

This may include:

• Anticoagulation
• Selected antiplatelet therapy

Anticoagulation should not be prescribed solely because an SLE patient has retinopathy; it is used when there is an established:

Thrombotic/APS indication.

Managing Retinal Ischemia

Extensive retinal nonperfusion with neovascularization may require:

Panretinal photocoagulation

Anti-VEGF therapy can be useful as an adjunct for:

• Neovascularization
• Macular edema

but it does not replace treatment of the underlying systemic disease.

Vitrectomy

Pars plana vitrectomy may be required for:

• Nonclearing vitreous hemorrhage
• Tractional retinal detachment
• Complex proliferative disease

Treating Lupus Choroidopathy

Treatment centers on correcting the underlying systemic problem:

• Control severe hypertension
• Treat active lupus nephritis
• Suppress systemic inflammation when appropriate

Serous detachments often improve as systemic disease comes under control.

Hydroxychloroquine in SLE

Hydroxychloroquine (HCQ) is a cornerstone systemic therapy for many patients with SLE because it reduces:

• Disease flares
• Thrombotic risk in selected populations
• Long-term organ damage

unless contraindicated.

Its major ophthalmic concern is:

Retinal toxicity.

Hydroxychloroquine Toxicity

HCQ toxicity primarily affects:

• Photoreceptors
• RPE

Typical advanced disease produces:

Bull’s-eye maculopathy

but modern screening aims to detect toxicity well before this appears clinically.

Safe Hydroxychloroquine Dosing

A major modern correction is that dosing should generally be kept at:

≤5 mg/kg/day using actual body weight

rather than the older threshold of 6.5 mg/kg based on ideal body weight.

Major Risk Factors for HCQ Retinopathy

Risk increases with:

• Higher daily dose
• Longer treatment duration
• Renal impairment
• Concurrent tamoxifen use

Pre-existing macular disease may complicate screening interpretation.

Modern HCQ Screening

Patients should have a:

Baseline ophthalmic examination

soon after starting therapy to document pre-existing macular disease and establish an imaging reference.

For patients at standard risk, annual screening generally begins after:

5 years of treatment.

Earlier annual screening is appropriate when major risk factors are present.

Core Hydroxychloroquine Screening Tests

Modern screening relies primarily on:

• Spectral-domain OCT
• Automated visual field testing

Common field strategy:

• 10-2 in many non-Asian patients

Because toxicity may be more pericentral in many Asian patients:

• Wider fields such as 24-2C, 24-2, or 30-2
• Wider OCT assessment

may be appropriate.

Additional HCQ Tests

Useful confirmatory tests include:

• Fundus autofluorescence
• Multifocal ERG

Amsler grid and color vision testing are:

Not sufficiently sensitive as primary screening tests.

Why Early HCQ Detection Is Critical

Hydroxychloroquine toxicity can continue to progress after the drug is stopped because of persistent retinal drug effects.

Therefore:

Established toxicity is irreversible.

The goal of screening is detection before meaningful central visual loss occurs.

Corneal Verticillata From Antimalarials

Antimalarial therapy may also cause:

Corneal verticillata

These whorl-like epithelial deposits are usually:

• Asymptomatic
• Reversible
• Not predictive of retinal toxicity

They generally do not require treatment.

Corticosteroid-Related Eye Problems

Patients treated chronically with systemic or topical steroids are at increased risk of:

• Posterior subcapsular cataract
• Ocular hypertension
• Steroid-induced glaucoma

These complications should be monitored during prolonged therapy.

Multidisciplinary Management

Serious ocular lupus manifestations often require collaboration among:

• Ophthalmology
• Rheumatology
• Nephrology
• Neurology
• Hematology

depending on the systemic phenotype.

Follow-Up Approach

Follow-up is individualized according to:

• Ocular manifestation
• Systemic activity
• Treatment
• Medication toxicity

Monitor as appropriate:

• Visual acuity
• IOP
• Ocular surface
• Optic nerve
• OCT
• Visual fields
• Retinal vascular status

Expected Visual Outcome

Most patients with uncomplicated dry eye or episcleritis maintain:

Excellent visual prognosis.

Visual prognosis becomes more guarded with:

• Severe vaso-occlusive retinopathy
• Macular ischemia
• Optic neuropathy
• Extensive choroidopathy
• Delayed treatment

Features Linked to Poorer Vision

Particularly concerning findings include:

• Extensive retinal capillary nonperfusion
• Macular ischemia
• Central retinal artery occlusion
• Neovascularization
• Optic nerve ischemia
• Recurrent severe inflammatory disease

Long-Term Eye Complications

Potential complications include:

• Chronic dry eye
• Corneal ulceration
• Scleritis
• Cataract
• Glaucoma
• Retinal vascular occlusion
• Vitreous hemorrhage
• Tractional retinal detachment
• Neovascular glaucoma
• Macular ischemia
• Optic neuropathy
• Permanent visual loss

High-Yield Takeaways

• SLE is a multisystem autoimmune disease capable of affecting essentially every ocular structure.
• The most common ophthalmic manifestation is usually ocular surface disease/dry eye, often associated with Sjögren disease.
• Lupus retinopathy classically produces cotton-wool spots, hemorrhages, microaneurysms, and vascular abnormalities.
• Retinal vascular disease may parallel active systemic or CNS lupus and can therefore be an important marker of disease severity.
• Severe vaso-occlusive retinopathy can produce extensive capillary nonperfusion, artery or vein occlusion, retinal neovascularization, vitreous hemorrhage, and tractional retinal detachment.
• Severe retinal thrombosis should raise suspicion for antiphospholipid syndrome.
• Anticoagulation is used for an appropriate APS/thrombotic indication, not automatically for all lupus retinopathy.
• Lupus choroidopathy may produce serous retinal detachment and is often associated with severe hypertension or lupus nephritis.
• In an SLE patient on corticosteroids, subretinal fluid may alternatively represent steroid-associated central serous chorioretinopathy.
• Scleritis and peripheral ulcerative keratitis generally require systemic treatment and may indicate severe autoimmune activity.
• Optic neuropathy is uncommon but potentially devastating and requires urgent systemic evaluation.
• In immunosuppressed SLE patients, always consider infection before labeling new ocular inflammation as a lupus flare.
• Hydroxychloroquine is an important systemic therapy for SLE, but retinal screening is essential.
• Modern HCQ dosing should generally be ≤5 mg/kg/day based on actual body weight.
• The major HCQ toxicity risk factors are high dose, long treatment duration, renal impairment, and tamoxifen use.
• Modern HCQ screening emphasizes OCT plus automated visual fields, with wider pericentral testing particularly important in many Asian patients.
• The old reliance on Amsler grid, color testing, or visible bull’s-eye maculopathy represents late and inadequate screening.
• Vision-threatening retinal vasculitis or choroidopathy requires rapid systemic disease control with rheumatology collaboration.
• The prognosis is generally good for mild ocular disease but can be poor with macular ischemia, severe vaso-occlusion, or optic nerve involvement.

Medicine – Hypercalcaemia

Hypercalcaemia means an abnormally increased concentration of calcium in the blood. The two most important causes are:

Primary hyperparathyroidism

and

Malignancy.

Together, these account for the great majority of clinically important cases. Primary hyperparathyroidism is particularly important in ambulatory patients, whereas malignancy is a major cause of more severe hypercalcaemia in hospitalised patients.

Hypercalcaemia can affect the kidneys, gastrointestinal tract, nervous system, muscles, bones and cardiovascular system. Severe or rapidly developing hypercalcaemia can become a medical emergency.

1. Definition of Hypercalcaemia

Hypercalcaemia is diagnosed when serum calcium exceeds the laboratory reference range.

Interpretation should take into account:

Albumin concentration

because a substantial proportion of circulating calcium is bound to albumin.

When the result is uncertain or the patient is critically ill, measurement of:

Ionised calcium

can provide a more direct assessment of biologically active calcium.

2. Regulation of Serum Calcium

Calcium balance is controlled primarily by:

Parathyroid hormone – PTH.

Vitamin D.

Kidneys.

Bone.

Gastrointestinal tract.

When serum calcium falls, PTH normally increases.

When calcium rises, PTH should become:

Suppressed.

This physiological relationship is extremely useful when investigating hypercalcaemia.

3. First Step in Finding the Cause

After confirming genuine hypercalcaemia, one of the most useful initial investigations is:

PTH.

Hypercalcaemia can then be broadly divided into:

PTH-dependent hypercalcaemia

and

PTH-independent hypercalcaemia.

4. PTH-Dependent Hypercalcaemia

If calcium is high but PTH is:

Elevated

or

Inappropriately normal,

PTH is contributing to the hypercalcaemia.

Important causes include:

Primary hyperparathyroidism.

Tertiary hyperparathyroidism.

Lithium-associated hyperparathyroidism/hypercalcaemia.

Familial hypocalciuric hypercalcaemia – FHH, an important differential diagnosis.

5. PTH-Independent Hypercalcaemia

If calcium is high and PTH is appropriately:

Suppressed,

consider non-parathyroid causes.

Important examples include:

Malignancy.

Vitamin D excess.

Sarcoidosis and other granulomatous disease.

Hyperthyroidism.

Milk-alkali/calcium-alkali syndrome.

Some medication-related causes also occur.

6. Primary Hyperparathyroidism

The original notes correctly identify:

Primary hyperparathyroidism

as one of the most common causes of hypercalcaemia.

The most common underlying lesion is:

A solitary parathyroid adenoma.

A single adenoma accounts for approximately:

80–85% of sporadic primary hyperparathyroidism.

7. Mechanism of Primary Hyperparathyroidism

Excessive PTH causes:

↑ Renal calcium reabsorption.

↑ Calcitriol production.

↑ Intestinal calcium absorption indirectly.

↑ Bone turnover.

At the same time:

↑ Renal phosphate excretion.

Therefore the characteristic biochemical pattern is:

Ca²⁺ ↑

PTH ↑ or inappropriately normal

Phosphate ↓ or low-normal

ALP normal or ↑.

8. Primary Hyperparathyroidism and Urinary Calcium

Urinary calcium is often:

Increased

because hypercalcaemia increases the filtered calcium load.

However, urinary calcium is variable and is not required to be elevated in every patient.

Urinary calcium is particularly useful for distinguishing primary hyperparathyroidism from:

Familial hypocalciuric hypercalcaemia – FHH.

9. Malignancy

The original notes correctly identify:

Malignancy

as another major cause of hypercalcaemia.

Hypercalcaemia of malignancy is often:

More rapid in onset and more severe

than the hypercalcaemia associated with uncomplicated primary hyperparathyroidism.

Several different mechanisms are possible.

10. PTH-Related Peptide

An important mechanism is tumour production of:

PTH-related peptide – PTHrP.

PTHrP acts on PTH receptors and produces effects resembling PTH, particularly:

Increased bone resorption

and

Increased renal calcium reabsorption.

This produces:

Humoral hypercalcaemia of malignancy.

11. PTHrP and PTH

Although PTHrP behaves similarly to PTH at the receptor:

The patient’s own PTH is suppressed.

Therefore:

Hypercalcaemia + low PTH + elevated PTHrP

supports:

Humoral hypercalcaemia of malignancy.

This distinction is important because most cancers do not produce actual PTH.

12. Squamous Cell Carcinoma

PTHrP production is classically associated with:

Squamous cell carcinomas.

Examples include squamous malignancies arising in sites such as:

Lung.

Head and neck.

Oesophagus.

Other malignancies can also produce PTHrP.

For examination purposes:

SQUAMOUS CELL CARCINOMA + HYPERCALCAEMIA → THINK PTHrP.

13. Osteolytic Bone Disease

The second major malignant mechanism is:

Local destruction of bone.

Tumour involvement of bone stimulates osteoclast-mediated:

Bone resorption.

Calcium is then released from bone into the circulation.

Therefore:

OSTEOLYTIC BONE DISEASE → BONE RESORPTION → Ca²⁺ RELEASE → HYPERCALCAEMIA.

14. Breast Cancer

The original notes correctly include:

Breast carcinoma.

Breast cancer can cause hypercalcaemia through:

Skeletal metastases with increased bone resorption

and, in some cases, humoral mechanisms.

Therefore a patient with advanced breast cancer and hypercalcaemia should be evaluated for:

Malignancy-associated hypercalcaemia.

15. Multiple Myeloma – Important Additional Cause

An important malignant cause not listed in the original notes is:

Multiple myeloma.

Myeloma stimulates osteoclast activity and produces:

Lytic bone lesions.

This can cause:

Bone pain.

Pathological fractures.

Hypercalcaemia.

The classic association is often remembered as part of:

CRAB:

C – HyperCalcaemia

R – Renal impairment

A – Anaemia

B – Bone lesions.

16. Renal Cell Carcinoma

The original notes include:

Kidney carcinoma.

More specifically:

Renal cell carcinoma – RCC

can cause hypercalcaemia as a:

Paraneoplastic manifestation.

PTHrP is one possible mechanism.

Therefore hypercalcaemia can occasionally occur even without extensive skeletal metastases.

17. Thyroid Carcinoma

The original notes include:

Thyroid carcinoma.

Hypercalcaemia can occur in advanced malignancy with skeletal involvement, but thyroid carcinoma is not among the most characteristic common causes of malignant hypercalcaemia compared with squamous cell carcinoma, breast cancer, renal cell carcinoma and multiple myeloma.

Therefore it should be considered a possible association rather than a classic leading cause.

18. Other Malignant Mechanisms

Some lymphomas can cause hypercalcaemia through increased production of:

1,25-dihydroxyvitamin D – calcitriol.

Therefore malignancy-associated hypercalcaemia is not explained solely by:

PTHrP or bone metastases.

The major mechanisms are:

PTHrP production.

Osteolytic bone resorption.

Excess calcitriol production in selected lymphomas.

Rarely, ectopic true PTH production.

19. Calcium Intake and Calcium-Alkali Syndrome

The original notes refer to:

Calcium intake and milk-alkali syndrome.

The modern term commonly used is:

Calcium-alkali syndrome.

It occurs after excessive intake of:

Calcium

together with absorbable:

Alkali, often calcium carbonate preparations.

20. Calcium-Alkali Syndrome

The characteristic combination is:

Hypercalcaemia.

Metabolic alkalosis.

Acute kidney injury or renal impairment.

Therefore:

HIGH Ca²⁺ + METABOLIC ALKALOSIS + AKI

should raise consideration of:

Calcium-alkali syndrome.

Ordinary dietary calcium intake alone rarely produces major hypercalcaemia when normal regulatory mechanisms and renal function are intact.

21. Vitamin D Excess

The original notes correctly include:

Excess vitamin D.

Vitamin D increases gastrointestinal absorption of:

Calcium

and

Phosphate.

Therefore excessive vitamin D activity can produce:

Hypercalcaemia

and often:

Hyperphosphataemia.

22. Vitamin D Toxicity

In vitamin D toxicity:

Calcium ↑

Phosphate may ↑

PTH ↓

because the hypercalcaemia suppresses normal parathyroid secretion.

Excessive vitamin D supplementation is one possible cause.

23. Tertiary Hyperparathyroidism

The original notes correctly include:

Tertiary hyperparathyroidism.

This usually develops after prolonged:

Secondary hyperparathyroidism, particularly in advanced CKD.

Persistent stimulation causes progressive parathyroid:

Hyperplasia.

Eventually the glands may become:

Autonomous.

24. Tertiary Hyperparathyroidism Pattern

Once autonomy develops:

PTH remains excessively elevated

despite:

Hypercalcaemia.

Therefore:

PTH ↑↑

Ca²⁺ ↑

and, in advanced CKD:

Phosphate is often ↑.

This distinguishes tertiary disease from ordinary CKD-related secondary hyperparathyroidism, in which calcium is usually:

Low or normal.

25. Hyperthyroidism

The original notes correctly include:

Hyperthyroidism.

Excess thyroid hormone increases:

Bone turnover.

When bone resorption becomes sufficiently increased:

Calcium is released from bone.

Therefore some patients with thyrotoxicosis develop:

Mild hypercalcaemia.

PTH should normally be:

Suppressed.

26. Sarcoidosis

The original notes correctly identify:

Sarcoidosis.

Sarcoid granulomas contain activated:

Macrophages.

These macrophages can express:

1α-hydroxylase.

This enzyme converts vitamin D to:

1,25-dihydroxyvitamin D – calcitriol.

27. Mechanism of Hypercalcaemia in Sarcoidosis

Increased extrarenal calcitriol production causes:

↑ Intestinal calcium absorption

↓

Hypercalcaemia

and sometimes:

Hypercalciuria.

Therefore:

SARCOIDOSIS → MACROPHAGE 1α-HYDROXYLASE → ↑ CALCITRIOL → ↑ Ca²⁺ ABSORPTION.

28. Other Granulomatous Diseases

This mechanism is not exclusive to sarcoidosis.

Other granulomatous disorders can occasionally increase extrarenal calcitriol production, including:

Tuberculosis

and some:

Fungal infections.

Therefore granulomatous disease should be considered when hypercalcaemia occurs with:

Suppressed PTH and elevated/inappropriately high calcitriol.

29. Thiazide Diuretics

The original notes correctly include:

Thiazide diuretics.

Thiazides increase calcium reabsorption in the:

Distal nephron.

Therefore:

↓ Urinary calcium excretion

and occasionally:

↑ Serum calcium.

30. Thiazides and Primary Hyperparathyroidism

Thiazide-associated hypercalcaemia is often relatively:

Mild.

Importantly, thiazides can sometimes uncover previously unrecognised:

Primary hyperparathyroidism.

Therefore persistent hypercalcaemia should not automatically be attributed entirely to the medication.

31. Lithium

The original notes correctly include:

Lithium.

Lithium can alter the relationship between serum calcium and the:

Calcium-sensing receptor – CaSR.

The parathyroid glands may require a higher calcium concentration before PTH secretion is suppressed.

Therefore lithium can cause:

Hyperparathyroidism

and:

Hypercalcaemia.

32. Immobilisation – Important Additional Cause

Prolonged immobilisation can increase:

Bone resorption.

This can cause hypercalcaemia, particularly in patients with:

High baseline bone turnover, such as some young people or patients with certain skeletal disorders.

Therefore:

Prolonged immobilisation → increased bone resorption → hypercalcaemia.

33. Clinical Features of Hypercalcaemia

The manifestations of hypercalcaemia depend on:

Severity.

Rate of rise.

Duration.

Underlying disease.

Mild chronic hypercalcaemia may be:

Asymptomatic.

Rapid or severe hypercalcaemia produces more pronounced symptoms.

34. Traditional Clinical Mnemonic

The classic manifestations can be remembered as:

“Stones, bones, abdominal groans and psychiatric overtones.”

A more complete version sometimes adds:

“Thrones”

to represent:

Polyuria.

This mnemonic captures renal, skeletal, gastrointestinal and neurological manifestations.

35. Lethargy and Malaise

The original notes correctly include:

Lethargy and malaise.

Patients may develop:

Fatigue.

Reduced concentration.

General weakness.

Low mood.

These manifestations become more prominent as calcium rises.

36. Neurological and Psychiatric Features

The original notes include:

Depression.

Confusion.

Psychosis.

Hypercalcaemia can cause a spectrum of neuropsychiatric abnormalities ranging from:

Fatigue and cognitive slowing

to:

Confusion, delirium and reduced consciousness in severe disease.

Severe hypercalcaemia can eventually cause:

Coma.

37. Muscle Weakness

The original notes correctly include:

Weakness.

Hypercalcaemia decreases neuromuscular excitability and may produce:

Generalised muscle weakness.

This contrasts with hypocalcaemia, which characteristically causes:

Increased neuromuscular excitability and tetany.

38. Polyuria and Polydipsia

The original notes correctly identify:

Polyuria and polydipsia.

Hypercalcaemia impairs the kidney’s ability to concentrate urine.

It can produce a form of:

Nephrogenic diabetes insipidus physiology.

Therefore:

Hypercalcaemia

↓

↓ Renal concentrating ability

↓

Polyuria

↓

Water loss

↓

Thirst and polydipsia.

39. Hypercalcaemia and Dehydration

Polyuria can lead to:

Volume depletion.

Dehydration then reduces renal calcium clearance and may worsen:

Hypercalcaemia.

This can create a vicious cycle:

Hypercalcaemia → polyuria → dehydration → ↓ renal calcium clearance → worse hypercalcaemia.

This is why fluid replacement is so important in severe symptomatic disease.

40. Constipation

The original notes correctly include:

Constipation.

Hypercalcaemia reduces gastrointestinal smooth-muscle activity.

Patients may develop:

Constipation.

Nausea.

Anorexia.

Abdominal discomfort.

Severe disease can occasionally produce:

Ileus.

41. Peptic Ulcer Disease

Older teaching commonly lists:

Peptic ulceration

as a feature of hypercalcaemia or hyperparathyroidism.

The association is much less diagnostically useful than the classic renal, neurological and gastrointestinal manifestations.

A particularly important association with peptic ulcer disease occurs when hyperparathyroidism is part of:

MEN1, because MEN1 can also include gastrin-producing neuroendocrine tumours causing Zollinger–Ellison syndrome.

Therefore peptic ulceration should not be regarded as a universal direct consequence of hypercalcaemia.

42. Renal Stones

The original notes correctly identify:

Renal stones.

Persistent hypercalcaemia and hypercalciuria can promote formation of:

Calcium-containing renal calculi.

This is particularly important in:

Primary hyperparathyroidism.

Patients may present with:

Renal colic

or:

Haematuria.

43. Nephrocalcinosis

The original notes correctly include:

Nephrocalcinosis.

This means deposition of calcium salts within:

Renal tissue.

Persistent abnormalities of calcium metabolism can contribute to:

Renal impairment.

Therefore chronic hypercalcaemia can damage the kidneys through both:

Stone formation

and

Nephrocalcinosis.

44. Pancreatitis

The original notes include:

Pancreatitis.

Hypercalcaemia, particularly in hyperparathyroidism, is a recognised but relatively uncommon association with:

Acute pancreatitis.

This creates an interesting bidirectional relationship:

Hypercalcaemia can be associated with pancreatitis,

while:

Severe acute pancreatitis can itself cause hypocalcaemia.

45. Cardiac Effects

Hypercalcaemia affects cardiac electrophysiology.

The classic ECG change is:

Shortening of the QT interval.

This is the opposite of hypocalcaemia, which classically produces:

QT prolongation.

Severe hypercalcaemia can also contribute to:

Arrhythmias.

46. Severe Hypercalcaemia

Marked hypercalcaemia may produce:

Profound dehydration.

Acute kidney injury.

Severe weakness.

Confusion or delirium.

Cardiac rhythm abnormalities.

Reduced consciousness or coma.

Severe symptomatic hypercalcaemia therefore requires:

Urgent treatment.

47. Investigation

Once hypercalcaemia is confirmed, the most useful initial etiological test is usually:

PTH.

The basic diagnostic division is:

HIGH Ca + non-suppressed PTH → PTH-dependent cause.

HIGH Ca + suppressed PTH → PTH-independent cause.

48. High Calcium With High or Inappropriately Normal PTH

Think primarily about:

Primary hyperparathyroidism.

Also consider:

Tertiary hyperparathyroidism.

Lithium-associated disease.

Familial hypocalciuric hypercalcaemia.

The clinical context, renal function, phosphate and urinary calcium help distinguish them.

49. High Calcium With Suppressed PTH

Think about:

Malignancy.

Vitamin D toxicity.

Sarcoidosis/granulomatous disease.

Hyperthyroidism.

Calcium-alkali syndrome.

Immobilisation.

Additional tests are selected according to the suspected cause.

50. Malignancy Investigation

When malignancy-associated hypercalcaemia is suspected, investigations may include:

PTHrP when clinically appropriate.

Serum and urine monoclonal protein studies/free light chains when myeloma is suspected.

Imaging according to symptoms and clinical context.

Vitamin D metabolites in selected cases such as suspected lymphoma-associated calcitriol excess.

51. Treatment Principles

Treatment depends on:

Severity of hypercalcaemia.

Symptoms.

Rate of rise.

Renal and cardiac function.

Underlying cause.

Mild stable hypercalcaemia may require primarily treatment of the cause, whereas severe symptomatic disease requires urgent calcium-lowering therapy.

52. Intravenous Fluids

The original notes correctly identify:

Rehydration

as a central treatment.

For significant symptomatic hypercalcaemia with volume depletion, treatment commonly begins with:

Intravenous isotonic saline, adjusted to the patient’s cardiovascular and renal status.

Restoring intravascular volume improves:

Renal perfusion

and:

Urinary calcium excretion.

53. “Aggressive” Rehydration – Important Qualification

The older phrase:

“Aggressive rehydration”

should be interpreted cautiously.

Fluid replacement should be:

Adequate but individualised.

Excessive fluids can be dangerous in patients with:

Heart failure

or:

Significant renal impairment.

Therefore hydration is guided by the patient’s:

Volume status, urine output and cardiorenal function.

54. Intravenous Bisphosphonates

The original notes correctly include:

Bisphosphonates.

These inhibit:

Osteoclast-mediated bone resorption.

They are particularly important in:

Hypercalcaemia of malignancy.

Examples include:

Zoledronic acid

and:

Pamidronate.

55. Pamidronate

The original note specifically lists:

Intravenous pamidronate.

This remains an effective treatment.

However, modern practice also commonly uses:

Intravenous zoledronic acid, depending on the clinical situation and renal function.

Bisphosphonates do not act instantly; their calcium-lowering effect develops over:

Days rather than minutes.

56. Calcitonin

An important acute treatment not included in the original notes is:

Calcitonin.

Calcitonin can reduce serum calcium relatively:

Rapidly.

Its effect begins faster than that of bisphosphonates.

However, the effect is relatively modest and:

Tachyphylaxis develops, limiting prolonged use.

Therefore it can be useful as a short-term measure in:

Severe symptomatic hypercalcaemia.

57. Denosumab

Denosumab inhibits:

RANKL

and therefore reduces osteoclast formation and activity.

It has an important role in selected cases of:

Hypercalcaemia of malignancy, particularly when hypercalcaemia is refractory to bisphosphonate therapy or when bisphosphonates are unsuitable.

Treatment choice depends on the clinical context and kidney function.

58. Furosemide – Important Correction

The original notes list:

Furosemide.

Historically, loop diuretics were routinely used after saline administration because they increase urinary calcium excretion.

However:

Routine furosemide is no longer recommended solely to treat hypercalcaemia.

It can worsen:

Volume depletion

and electrolyte abnormalities.

59. When Furosemide May Be Used

A loop diuretic may still be useful when there is a specific indication, particularly:

Fluid overload after adequate rehydration.

Therefore the modern principle is:

REHYDRATE FIRST.

Then use a loop diuretic only when clinically required for:

Volume management, rather than routinely forcing calcium diuresis.

60. Corticosteroids

The original notes correctly include:

Steroids, but they are not useful for every cause of hypercalcaemia.

Glucocorticoids are particularly useful in hypercalcaemia driven by excessive:

Calcitriol activity.

Examples include:

Sarcoidosis.

Other granulomatous diseases.

Some lymphomas.

Selected vitamin D-mediated hypercalcaemia.

61. Why Steroids Work in Sarcoidosis

Glucocorticoids reduce abnormal macrophage-mediated production of:

Calcitriol.

Therefore:

↓ Calcitriol

↓

↓ Intestinal calcium absorption

↓

↓ Serum calcium.

Hence:

SARCOIDOSIS + HYPERCALCAEMIA → GLUCOCORTICOIDS CAN BE EFFECTIVE.

62. Treat the Underlying Cause

Definitive management depends on the cause.

For example:

Primary hyperparathyroidism → parathyroidectomy when indicated.

Malignancy → treat malignancy plus acute calcium control.

Vitamin D toxicity → stop excessive vitamin D and manage hypercalcaemia.

Calcium-alkali syndrome → stop calcium/alkali excess and restore volume appropriately.

Sarcoidosis → glucocorticoids in appropriate symptomatic hypercalcaemic disease.

Medication-associated hypercalcaemia → review/stop the responsible drug when appropriate.

63. Dialysis

In selected patients with severe hypercalcaemia, particularly when there is:

Severe kidney failure,

refractory hypercalcaemia,

or an inability to safely administer adequate intravenous fluids,

dialysis may be considered.

This is reserved for severe clinical circumstances rather than routine hypercalcaemia.

64. Causes of Hypercalcaemia – Note Form

PTH-DEPENDENT

Primary hyperparathyroidism – most commonly a solitary parathyroid adenoma.

Tertiary hyperparathyroidism.

Lithium-associated hyperparathyroidism.

Familial hypocalciuric hypercalcaemia.

MALIGNANCY

PTHrP production – particularly squamous cell carcinoma.

Osteolytic bone disease/metastases – including breast cancer.

Multiple myeloma.

Renal cell carcinoma – possible PTHrP/paraneoplastic mechanism.

Calcitriol production – selected lymphomas.

VITAMIN D/CALCITRIOL RELATED

Vitamin D toxicity.

Sarcoidosis.

Other granulomatous disease.

Selected lymphomas.

MEDICATIONS

Thiazide diuretics.

Lithium.

Excess calcium/vitamin D preparations.

OTHER

Calcium-alkali syndrome.

Hyperthyroidism.

Prolonged immobilisation.

65. Features of Hypercalcaemia – Note Form

GENERAL/NEUROMUSCULAR

Lethargy.

Malaise.

Fatigue.

Muscle weakness.

NEUROPSYCHIATRIC

Poor concentration.

Low mood.

Confusion.

Delirium.

Severe cases → reduced consciousness/coma.

RENAL

Polyuria.

Polydipsia.

Dehydration.

Renal stones.

Nephrocalcinosis.

Renal impairment.

GASTROINTESTINAL

Constipation.

Nausea.

Abdominal discomfort.

Anorexia.

Occasionally pancreatitis.

CARDIAC

Short QT interval.

Arrhythmias in severe disease.

66. Treatment – Note Form

1. REHYDRATION

IV isotonic saline when clinically indicated.

Correct volume depletion while avoiding fluid overload.

2. ANTIRESORPTIVE THERAPY

IV bisphosphonate such as:

Zoledronic acid

or:

Pamidronate, particularly in malignancy-associated hypercalcaemia.

Denosumab in selected cases.

3. RAPID TEMPORARY CALCIUM LOWERING

Calcitonin for selected severe symptomatic cases.

4. GLUCOCORTICOIDS

Particularly useful for:

Sarcoidosis.

Other granulomatous disease.

Selected lymphoma/vitamin D-mediated hypercalcaemia.

5. LOOP DIURETICS

Not routinely used solely to lower calcium.

Consider only for a specific indication such as:

Fluid overload after adequate rehydration.

6. DEFINITIVE TREATMENT

Treat the underlying:

Parathyroid disease, malignancy, medication effect, vitamin D excess or granulomatous disorder.

67. Important Corrections to the Original Notes

The original:

“Some tumours secrete a PTH-related protein”

is correct.

Remember:

PTHrP ↑ but endogenous PTH ↓.

The tumour usually does not produce ordinary PTH.

The original:

“Bone metastases lead to destruction of bone and calcium release”

is also correct for:

Osteolytic skeletal disease.

However, an important additional malignant cause is:

Multiple myeloma.

The original list includes:

Thyroid carcinoma.

This can be associated with hypercalcaemia in advanced disease, but it is less characteristic than:

Squamous cell carcinoma + breast cancer + renal cell carcinoma + multiple myeloma.

The original:

“Milk-alkali syndrome”

is now commonly called:

CALCIUM-ALKALI SYNDROME.

Remember the triad:

HYPERCALCAEMIA + METABOLIC ALKALOSIS + RENAL IMPAIRMENT.

The original:

“Furosemide”

requires an important modern correction:

Do not routinely use furosemide simply to lower calcium.

It may worsen dehydration. Use it mainly when there is a specific need to manage:

Fluid overload after adequate rehydration.

The original:

“Steroids”

also requires qualification.

Steroids are particularly useful for:

CALCITRIOL-MEDIATED HYPERCALCAEMIA, such as sarcoidosis and selected lymphomas, rather than all forms of hypercalcaemia.

Key Clinical Pattern

The most important first diagnostic distinction is:

HYPERCALCAEMIA → CHECK PTH.

Ca ↑ + PTH ↑/INAPPROPRIATELY NORMAL

Think:

PRIMARY HYPERPARATHYROIDISM

first, while considering tertiary disease, lithium and FHH according to context.

Ca ↑ + PTH ↓

Think:

MALIGNANCY + VITAMIN D EXCESS + SARCOIDOSIS + HYPERTHYROIDISM + CALCIUM-ALKALI SYNDROME.

For malignancy:

SQUAMOUS CELL CARCINOMA → PTHrP.

BREAST CANCER/MYELOMA → OSTEOLYTIC BONE RESORPTION.

SOME LYMPHOMAS → ↑ CALCITRIOL.

For symptoms remember:

“STONES, BONES, ABDOMINAL GROANS, THRONES AND PSYCHIATRIC OVERTONES.”

Stones → renal calculi.

Bones → skeletal disease.

Groans → constipation/abdominal symptoms.

Thrones → polyuria.

Psychiatric overtones → lethargy, confusion and neuropsychiatric disturbance.

And the classic ECG distinction is:

HYPERCALCAEMIA → SHORT QT.

HYPOCALCAEMIA → LONG QT.

Medicine – Hyperparathyroidism

Hyperparathyroidism is a disorder in which the parathyroid glands produce excessive parathyroid hormone (PTH). PTH normally maintains serum calcium by acting on the kidneys and bone and by increasing renal production of active vitamin D, which enhances intestinal calcium absorption.

Hyperparathyroidism is divided into three major forms:

Primary hyperparathyroidism – autonomous excessive PTH secretion from the parathyroid glands.

Secondary hyperparathyroidism – compensatory PTH elevation in response to a chronic stimulus, especially chronic kidney disease or vitamin D deficiency.

Tertiary hyperparathyroidism – autonomous PTH secretion developing after prolonged secondary hyperparathyroidism, most often in advanced CKD.

1. Normal Actions of PTH

PTH is secreted by the:

Parathyroid glands.

Its major physiological purpose is to maintain an adequate concentration of:

Ionised calcium.

When serum calcium falls:

↓ Ca²⁺

↓

Parathyroid calcium-sensing receptors detect the change

↓

↑ PTH secretion

↓

Serum calcium is restored toward normal.

2. PTH and Calcium

PTH raises serum calcium through several mechanisms.

In the kidney, PTH:

Increases calcium reabsorption.

It also stimulates:

1α-hydroxylase

which increases production of:

1,25-dihydroxyvitamin D – calcitriol.

Calcitriol then increases intestinal:

Calcium absorption.

PTH also increases bone turnover and, through its effects on osteoblast-lineage cells and osteoclast activation, can increase calcium release from bone when persistently elevated.

3. PTH and Phosphate

PTH has the opposite effect on serum phosphate.

In the proximal renal tubule, PTH:

Decreases phosphate reabsorption.

Therefore:

↑ PTH

↓

↑ Urinary phosphate excretion

↓

Phosphaturia

↓

↓ Serum phosphate.

A useful rule is:

PTH RAISES CALCIUM AND LOWERS PHOSPHATE.

4. Primary Hyperparathyroidism

Primary hyperparathyroidism occurs when one or more parathyroid glands secrete PTH autonomously.

The excessive PTH secretion is inappropriate for the patient’s serum calcium concentration.

Therefore the typical biochemical pattern is:

PTH ↑ or inappropriately normal

with:

Calcium ↑.

5. Parathyroid Adenoma

The original notes correctly state that the most common cause is:

A single parathyroid adenoma.

A solitary benign adenoma accounts for the large majority of sporadic cases, traditionally quoted as approximately:

80–85%.

Therefore:

PRIMARY HYPERPARATHYROIDISM → THINK SINGLE PARATHYROID ADENOMA FIRST.

6. Other Causes of Primary Hyperparathyroidism

Other causes include:

Multigland parathyroid hyperplasia.

Less commonly:

Multiple adenomas.

Very rarely:

Parathyroid carcinoma.

Therefore not every patient with primary hyperparathyroidism has a single adenoma.

7. Familial Primary Hyperparathyroidism

Primary hyperparathyroidism may occasionally occur as part of inherited endocrine syndromes.

Important associations include:

Multiple endocrine neoplasia type 1 – MEN1.

MEN2A.

Other inherited hyperparathyroidism syndromes also exist.

In familial disease, involvement of:

Multiple parathyroid glands

is more likely than in a typical sporadic single adenoma.

8. Epidemiology

The original notes correctly identify a predominance in:

Women.

Primary hyperparathyroidism is more common in women than men and becomes increasingly common with age, particularly around and after:

Menopause.

The traditional teaching of:

Women aged 40–60 years

captures an important demographic group, although the disorder can occur outside this age range.

9. Clinical Presentation

Many patients are now diagnosed when routine blood tests reveal:

Hypercalcaemia.

Therefore primary hyperparathyroidism may initially be:

Asymptomatic.

When symptoms occur, many are manifestations of:

Hypercalcaemia

or chronic PTH excess.

10. “Stones, Bones, Groans and Psychiatric Overtones”

The traditional mnemonic for symptomatic hyperparathyroidism/hypercalcaemia is:

Stones.

Bones.

Abdominal groans.

Psychiatric overtones.

This summarises renal, skeletal, gastrointestinal and neuropsychiatric manifestations.

11. Renal Features – “Stones”

Hypercalcaemia and increased filtered calcium can predispose to:

Nephrolithiasis – renal stones.

Patients may therefore develop:

Renal colic.

Haematuria.

Recurrent calcium-containing renal calculi.

Chronic disease can also be associated with:

Nephrocalcinosis

and impaired renal function.

12. Urinary Calcium

The original notes state:

Urinary calcium ↑.

This is often true in primary hyperparathyroidism because the increased serum calcium raises the filtered calcium load.

However, urinary calcium is not invariably elevated, so this should not be treated as an absolute diagnostic requirement.

Urinary calcium measurement is particularly useful when distinguishing primary hyperparathyroidism from:

Familial hypocalciuric hypercalcaemia – FHH.

13. Familial Hypocalciuric Hypercalcaemia

FHH can resemble primary hyperparathyroidism because it can produce:

Hypercalcaemia

with:

PTH that is normal or mildly elevated.

However, FHH characteristically has:

Low urinary calcium excretion.

Therefore assessment of urinary calcium, often using the:

Calcium-to-creatinine clearance ratio,

can help distinguish FHH from primary hyperparathyroidism.

This distinction matters because FHH generally does not benefit from routine parathyroidectomy.

14. Skeletal Features – “Bones”

Persistent PTH excess increases:

Bone turnover.

Severe longstanding disease can cause:

Bone pain.

Reduced bone mineral density.

Osteoporosis.

Fragility fractures.

A classical severe skeletal manifestation is:

Osteitis fibrosa cystica.

15. Osteitis Fibrosa Cystica

Severe PTH excess can produce marked bone resorption and fibrous replacement.

Radiological findings may include:

Subperiosteal bone resorption, classically affecting the phalanges.

Brown tumours.

Salt-and-pepper appearance of the skull.

These findings are much less common in modern patients diagnosed early.

16. Brown Tumours

A brown tumour is not a true neoplasm.

It represents an area of excessive bone resorption with:

Fibrous tissue.

Haemorrhage.

Hemosiderin deposition.

It can occur in severe:

Primary, secondary or tertiary hyperparathyroidism.

17. Gastrointestinal Features – “Groans”

Hypercalcaemia can cause:

Constipation.

Nausea.

Abdominal discomfort.

Reduced appetite.

More severe hypercalcaemia may produce:

Vomiting and dehydration.

18. Neuropsychiatric Features

Hypercalcaemia may produce:

Fatigue.

Muscle weakness.

Poor concentration.

Low mood or other neuropsychiatric symptoms.

Severe hypercalcaemia can cause:

Confusion

and eventually impaired consciousness.

19. Investigations in Primary Hyperparathyroidism

The original notes give:

↑ PTH

↑ serum calcium

↑ urinary calcium

↑ ALP

↓ serum phosphate.

This is a useful classical pattern, but several points require qualification.

20. Serum Calcium

The defining biochemical abnormality in classical primary hyperparathyroidism is:

Hypercalcaemia

together with PTH that is:

Elevated or inappropriately normal.

Why “inappropriately normal”?

When calcium is high, normal physiology should:

Suppress PTH.

Therefore even a PTH concentration within the laboratory reference range may be abnormal if it fails to suppress in the presence of hypercalcaemia.

21. Serum Phosphate

PTH causes:

Phosphaturia.

Therefore serum phosphate is commonly:

Low

or:

Low-normal.

Hence:

↑ Ca²⁺ + ↓ PO₄³⁻ + non-suppressed PTH → strongly suggests primary hyperparathyroidism.

22. Alkaline Phosphatase

The original notes state:

ALP ↑.

This can occur when PTH excess produces increased:

Bone turnover.

However, ALP may be:

Normal in mild disease.

Therefore a more accurate pattern is:

ALP normal or ↑.

Marked elevation suggests substantial skeletal involvement or another source of ALP that should be considered.

23. Vitamin D and Renal Function

Assessment commonly also includes:

Renal function.

25-hydroxyvitamin D.

Vitamin D deficiency may coexist with primary hyperparathyroidism and can influence:

PTH concentration and skeletal disease.

24. Imaging the Parathyroid Glands

An important principle is:

Primary hyperparathyroidism is diagnosed biochemically, not by imaging.

Imaging is generally performed after the biochemical diagnosis when surgery is being considered.

Its purpose is to:

Localise the abnormal gland or glands.

25. Localisation Studies

Localisation may involve:

Neck ultrasound.

Technetium-99m sestamibi imaging.

Additional imaging may be used in selected patients.

Therefore:

Blood tests establish the diagnosis.

Imaging helps plan surgery.

26. Treatment of Primary Hyperparathyroidism

The definitive treatment for appropriate patients is:

Parathyroidectomy.

Surgery is particularly considered when disease is symptomatic or when established guideline criteria are met, such as significant hypercalcaemia, skeletal involvement, renal involvement or particular age/risk considerations.

Patients who do not undergo surgery require appropriate:

Biochemical, renal and skeletal monitoring.

27. Secondary Hyperparathyroidism

The original notes correctly state that secondary hyperparathyroidism results from:

Compensatory enlargement and increased activity of the parathyroid glands in response to a chronic stimulus lowering calcium or disturbing mineral metabolism.

The glands themselves are initially responding appropriately.

Therefore:

Secondary hyperparathyroidism is compensatory rather than initially autonomous.

28. Chronic Kidney Disease – Major Cause

The classic cause is:

Chronic kidney disease.

As renal function declines:

Phosphate excretion decreases

and:

Calcitriol production decreases.

These changes disturb calcium-phosphate homeostasis and stimulate:

PTH secretion.

29. Mechanism in CKD

The sequence can be simplified as:

CKD

↓

↓ Phosphate excretion

↓

Phosphate retention

• ●

↓ Renal 1α-hydroxylation

↓

↓ Calcitriol

↓

↓ Intestinal calcium absorption

↓

Low/low-normal Ca²⁺

↓

↑ PTH.

FGF23 also increases early in CKD and contributes to reduced calcitriol production.

30. Parathyroid Hyperplasia

Persistent stimulation causes the parathyroid glands to undergo:

Hyperplasia.

Therefore:

LONG-STANDING CKD → CHRONIC PTH STIMULATION → PARATHYROID HYPERPLASIA → SECONDARY HYPERPARATHYROIDISM.

This contributes to:

CKD–mineral and bone disorder.

31. Biochemical Pattern in CKD Secondary Hyperparathyroidism

A typical pattern in advanced CKD is:

PTH ↑

Calcium ↓ or normal

Phosphate ↑

Calcitriol ↓

ALP normal or ↑, depending on bone turnover.

The combination of:

HIGH PTH + HIGH PHOSPHATE

is particularly suggestive of advanced CKD-related secondary hyperparathyroidism.

32. Renal Osteodystrophy

Longstanding secondary hyperparathyroidism can cause high-turnover bone disease known as:

Osteitis fibrosa.

This forms part of the broader spectrum of:

Renal osteodystrophy.

Patients may develop:

Bone pain.

Fractures.

Skeletal abnormalities.

33. Vitamin D Deficiency – Another Major Cause

Secondary hyperparathyroidism is not limited to renal failure.

Another very important cause is:

Vitamin D deficiency.

Reduced vitamin D causes:

↓ Intestinal calcium absorption

↓

Tendency toward ↓ Ca²⁺

↓

Compensatory ↑ PTH.

34. Pattern in Vitamin D Deficiency

Vitamin D deficiency with secondary hyperparathyroidism typically produces:

PTH ↑

Calcium ↓ or low-normal

Phosphate ↓

ALP ↑

25(OH) vitamin D ↓.

The phosphate is low because increased PTH causes:

Renal phosphate wasting.

35. Other Causes of Secondary Hyperparathyroidism

Other causes can include conditions that impair calcium or vitamin D availability, such as:

Malabsorption.

Low calcium intake in appropriate circumstances.

Disorders of vitamin D metabolism.

The unifying principle is:

The parathyroid glands are responding to a chronic physiological stimulus.

36. Treatment of Secondary Hyperparathyroidism

Treatment focuses primarily on:

Correcting the underlying stimulus.

In vitamin D deficiency this means:

Vitamin D replacement and adequate calcium intake.

In CKD, management may involve:

Phosphate control.

Dietary measures.

Phosphate binders when indicated.

Vitamin D or active vitamin D therapy in selected patients.

Calcimimetics such as cinacalcet in selected dialysis patients.

Management is guided by the overall pattern of:

Calcium + phosphate + PTH + ALP, rather than PTH alone.

37. Tertiary Hyperparathyroidism

The original notes correctly state that tertiary hyperparathyroidism develops as a consequence of:

Long-standing secondary hyperparathyroidism.

It is classically associated with:

Longstanding advanced CKD.

38. Development of Autonomy

During prolonged secondary hyperparathyroidism:

Chronic stimulation

↓

Parathyroid hyperplasia

↓

Progressive gland enlargement

↓

Reduced responsiveness to normal regulatory signals

↓

Autonomous PTH secretion.

At this point, PTH secretion continues even when calcium is no longer low.

This represents:

Tertiary hyperparathyroidism.

39. Calcium Rises in Tertiary Hyperparathyroidism

This is the key difference from secondary hyperparathyroidism.

In secondary disease:

PTH ↑

but calcium is usually:

Low or normal.

In tertiary disease:

PTH becomes autonomously very high

and calcium becomes:

High.

Therefore:

TERTIARY HYPERPARATHYROIDISM = HIGH PTH + HYPERCALCAEMIA AFTER LONG-STANDING SECONDARY HYPERPARATHYROIDISM.

40. Biochemical Pattern of Tertiary Hyperparathyroidism

The characteristic pattern is:

PTH ↑↑

Calcium ↑

Phosphate is often:

↑ in advanced CKD

because renal phosphate excretion remains impaired.

ALP may also be elevated when there is substantial:

High-turnover bone disease.

41. Secondary Versus Tertiary Hyperparathyroidism

The easiest distinction is the serum calcium.

SECONDARY HYPERPARATHYROIDISM DUE TO CKD

PTH:

↑

Calcium:

↓ or normal

Phosphate:

↑

TERTIARY HYPERPARATHYROIDISM

PTH:

↑↑

Calcium:

↑

Phosphate:

Often ↑ in advanced CKD.

Therefore:

CKD + HIGH PTH + LOW/NORMAL Ca → SECONDARY.

CKD + VERY HIGH PTH + HIGH Ca → CONSIDER TERTIARY.

42. Treatment of Tertiary Hyperparathyroidism

The original notes state:

Parathyroidectomy is the treatment of choice.

Surgery remains an important definitive treatment for severe or refractory autonomous hyperparathyroidism, particularly when there is significant:

Hypercalcaemia.

Bone disease.

Symptoms.

or failure of appropriate medical management.

However, modern management is individualised, and selected patients may also be treated medically with agents such as:

Calcimimetics.

Therefore parathyroidectomy should not be interpreted as automatically required in every patient.

43. Primary Hyperparathyroidism – Note Form

MECHANISM

Autonomous PTH secretion.

MOST COMMON CAUSE

Single parathyroid adenoma:

Approximately 80–85% of sporadic cases.

OTHER CAUSES

Multigland hyperplasia.

Multiple adenomas.

Rare parathyroid carcinoma.

Familial syndromes such as MEN1/MEN2A.

BIOCHEMISTRY

PTH:

↑ or inappropriately normal

Calcium:

↑

Phosphate:

↓ or low-normal

ALP:

Normal or ↑

Urinary calcium:

Often ↑, but variable.

CLINICAL FEATURES

Renal stones.

Bone disease.

Constipation/abdominal symptoms.

Fatigue and weakness.

Neuropsychiatric symptoms.

Often asymptomatic and detected through hypercalcaemia.

44. Secondary Hyperparathyroidism – Note Form

MECHANISM

Appropriate compensatory increase in PTH caused by chronic disturbances of calcium/phosphate/vitamin D metabolism.

MAJOR CAUSES

Chronic kidney disease.

Vitamin D deficiency.

Malabsorption and other causes of chronic calcium/vitamin D deficiency.

ADVANCED CKD PATTERN

PTH:

↑

Calcium:

↓ or normal

Phosphate:

↑

Calcitriol:

↓

VITAMIN D DEFICIENCY PATTERN

PTH:

↑

Calcium:

↓ or low-normal

Phosphate:

↓

ALP:

↑

25(OH)D:

↓

45. Tertiary Hyperparathyroidism – Note Form

MECHANISM

Long-standing secondary hyperparathyroidism

↓

Parathyroid hyperplasia

↓

Autonomous PTH secretion.

CLASSIC SETTING

Long-standing:

Advanced CKD.

BIOCHEMISTRY

PTH:

↑↑

Calcium:

↑

Phosphate:

Often ↑ in advanced CKD.

TREATMENT

Control CKD-related mineral abnormalities.

Calcimimetic therapy in selected patients.

Parathyroidectomy for severe/refractory disease when indicated.

46. Important Corrections to the Original Notes

The original:

“Single adenoma in >80%”

is a good high-yield rule.

A solitary adenoma causes approximately:

80–85% of sporadic primary hyperparathyroidism.

The original:

“↑ PTH, ↑ serum and urinary calcium, ↑ ALP and ↓ serum phosphate”

should be refined to:

PTH ↑ or inappropriately normal.

Serum calcium ↑.

Phosphate ↓ or low-normal.

ALP normal or ↑.

Urinary calcium often ↑ but variable.

The original secondary hyperparathyroidism mechanism is correct, but secondary disease is not caused only by:

Renal failure.

Another major cause is:

Vitamin D deficiency.

The original description of tertiary disease as:

“Further gland hyperplasia raises calcium levels”

is broadly correct, but the central concept is:

The hyperplastic parathyroid tissue becomes functionally autonomous after prolonged secondary stimulation.

Therefore:

PTH remains excessively elevated despite hypercalcaemia.

The original:

“Parathyroidectomy is the treatment of choice”

is most applicable to significant, refractory tertiary hyperparathyroidism requiring definitive treatment. Medical therapy, particularly:

Calcimimetics,

may also be appropriate in selected patients.

47. Key Biochemical Patterns

PRIMARY HYPERPARATHYROIDISM

Ca ↑ | PTH ↑ | PO₄ ↓

Think:

Parathyroid adenoma.

SECONDARY HYPERPARATHYROIDISM – CKD

Ca ↓/normal | PTH ↑ | PO₄ ↑

Think:

Phosphate retention + reduced calcitriol.

SECONDARY HYPERPARATHYROIDISM – VITAMIN D DEFICIENCY

Ca ↓/low-normal | PTH ↑ | PO₄ ↓ | ALP ↑

Think:

Reduced intestinal calcium absorption → compensatory PTH elevation.

TERTIARY HYPERPARATHYROIDISM

Ca ↑ | PTH ↑↑ | PO₄ often ↑ in advanced CKD

Think:

Long-standing secondary hyperparathyroidism → autonomous glands.

Key Clinical Pattern

The simplest way to distinguish the three forms is to ask:

WHY IS PTH HIGH, AND WHAT IS THE CALCIUM DOING?

PRIMARY:

The parathyroid gland itself is abnormal.

PTH ↑ → Ca ↑ → phosphate ↓.

SECONDARY:

The parathyroid gland is responding appropriately to another problem.

In CKD:

Ca ↓/normal → PTH ↑, with phosphate ↑.

In vitamin D deficiency:

Ca ↓/low-normal → PTH ↑, with phosphate ↓.

TERTIARY:

After prolonged secondary stimulation, the glands become:

AUTONOMOUS.

Therefore:

PTH ↑↑ + Ca ↑, usually in the setting of long-standing advanced CKD.

For examination recall:

PRIMARY = HIGH PTH + HIGH CALCIUM.

SECONDARY = HIGH PTH + LOW/NORMAL CALCIUM.

TERTIARY = VERY HIGH PTH + HIGH CALCIUM AFTER LONG-STANDING SECONDARY DISEASE.

Medicine – Hypocalcaemia

Hypocalcaemia means a reduction in the concentration of calcium in the blood, particularly the physiologically active ionised calcium fraction. Calcium is essential for normal neuromuscular activity, cardiac electrical function, bone mineralisation, intracellular signalling and coagulation.

The major causes include hypoparathyroidism, vitamin D deficiency, chronic kidney disease, hypomagnesaemia, hyperphosphataemia, severe illness such as sepsis, acute pancreatitis and alkalosis.

The clinical manifestations are mainly caused by increased neuromuscular excitability and become more pronounced when calcium falls rapidly or reaches very low concentrations.

1. Calcium in the Blood

Circulating calcium exists in three main forms:

Ionised calcium – biologically active.

Albumin-bound calcium.

Calcium complexed with anions such as phosphate and citrate.

Approximately half of circulating calcium is present as:

Ionised Ca²⁺.

It is the ionised fraction that directly influences:

Nerve and muscle excitability.

2. Total Calcium and Albumin

Because a substantial proportion of calcium is bound to:

Albumin,

a low albumin concentration can produce a low measured total calcium even when ionised calcium is normal.

This is sometimes referred to as:

Pseudohypocalcaemia due to hypoalbuminaemia.

Therefore a low total calcium should be interpreted alongside:

Albumin

or, when appropriate, directly measured:

Ionised calcium.

3. Regulation of Serum Calcium

Serum calcium is principally regulated by:

PTH.

Vitamin D.

Kidneys.

Bone.

Gastrointestinal tract.

PTH and vitamin D work together to maintain adequate extracellular calcium.

4. Role of PTH

When ionised calcium falls:

↓ Ca²⁺

↓

Parathyroid glands detect the fall

↓

↑ PTH

↓

↑ Renal calcium reabsorption

• ●

↑ Renal calcitriol production

• ●

Effects on bone mineral metabolism

↓

Serum calcium rises toward normal.

PTH also increases renal phosphate excretion.

Therefore PTH can be remembered as:

PTH RAISES CALCIUM AND LOWERS PHOSPHATE.

5. Causes of Hypocalcaemia

The original notes identify several important causes:

Hypoparathyroidism.

Chronic renal failure.

Vitamin D deficiency.

Hyperphosphataemia.

Hypomagnesaemia.

Sepsis.

Respiratory alkalosis.

Acute pancreatitis.

Prostate carcinoma.

These causes produce hypocalcaemia through different mechanisms.

6. Hypoparathyroidism

The original notes correctly identify:

Hypoparathyroidism

as an important cause.

PTH normally raises serum calcium.

Therefore:

↓ PTH

↓

↓ Renal calcium reabsorption

• ●

↓ Calcitriol production

↓

↓ Serum calcium.

At the same time, reduced PTH causes reduced renal phosphate excretion.

Therefore:

Phosphate rises.

7. Biochemical Pattern of Hypoparathyroidism

The classic pattern is:

Ca²⁺ ↓

PO₄³⁻ ↑

PTH ↓ or inappropriately normal.

Important causes include:

Neck surgery/parathyroidectomy.

Autoimmune destruction.

DiGeorge syndrome.

Genetic disorders affecting parathyroid development or function.

8. Chronic Kidney Disease

The original notes correctly include:

Chronic renal failure, now usually termed chronic kidney disease – CKD.

Hypocalcaemia in advanced CKD is related to several abnormalities in mineral metabolism.

One important mechanism is reduced renal production of:

Calcitriol – active vitamin D.

9. CKD and Vitamin D

The kidneys normally convert:

25-hydroxyvitamin D

into:

1,25-dihydroxyvitamin D – calcitriol.

In advanced CKD:

↓ Functional renal mass

↓

↓ Calcitriol production

↓

↓ Intestinal calcium absorption

↓

Tendency toward hypocalcaemia.

10. CKD and Phosphate Retention

Advanced CKD also reduces renal:

Phosphate excretion.

Therefore:

↓ GFR

↓

Phosphate retention

↓

Hyperphosphataemia.

High phosphate contributes to abnormalities in calcium-phosphate balance and stimulates:

Secondary hyperparathyroidism.

11. CKD Biochemical Pattern

A typical pattern in advanced CKD with secondary hyperparathyroidism is:

Calcium ↓ or normal

Phosphate ↑

PTH ↑

Calcitriol ↓

ALP may be ↑.

This forms part of:

CKD–mineral and bone disorder – CKD-MBD.

12. Vitamin D Deficiency

The original notes correctly include:

Low vitamin D levels.

Vitamin D increases intestinal absorption of:

Calcium

and

Phosphate.

Therefore:

↓ Vitamin D

↓

↓ Intestinal calcium absorption

↓

Tendency toward:

Hypocalcaemia.

13. Secondary Hyperparathyroidism in Vitamin D Deficiency

When calcium falls because of vitamin D deficiency:

PTH increases.

PTH attempts to maintain serum calcium but simultaneously causes:

Renal phosphate wasting.

Therefore significant vitamin D deficiency classically produces:

Ca²⁺ ↓ or low-normal

PO₄³⁻ ↓

PTH ↑

ALP ↑

25(OH) vitamin D ↓.

14. Vitamin D Deficiency and Osteomalacia

Persistent vitamin D deficiency can impair:

Bone mineralisation.

In adults this produces:

Osteomalacia.

In children it produces:

Rickets.

Clinical features can include:

Bone pain.

Proximal muscle weakness.

Fractures or pseudofractures.

Skeletal deformity.

15. Hyperphosphataemia

The original notes correctly include:

Hyperphosphataemia.

A substantial increase in phosphate can lower ionised calcium and promote calcium-phosphate deposition.

Therefore:

↑ PO₄³⁻

↓

↓ Ca²⁺.

Important settings include:

Advanced CKD

and

Tumour lysis syndrome.

16. Tumour Lysis Syndrome

Tumour lysis syndrome causes rapid release of intracellular:

Potassium.

Phosphate.

Nucleic acids.

Therefore the characteristic biochemical pattern is:

K⁺ ↑

PO₄³⁻ ↑

Uric acid ↑

Ca²⁺ ↓

with possible:

Acute kidney injury.

The hypocalcaemia is closely related to the marked:

Hyperphosphataemia.

17. Hypomagnesaemia

The original notes correctly identify:

Hypomagnesaemia.

Magnesium is necessary for normal:

PTH secretion

and

PTH action.

Severe magnesium deficiency therefore causes:

↓ PTH secretion

and

PTH resistance.

Both mechanisms can produce:

Hypocalcaemia.

18. Refractory Hypocalcaemia

An extremely useful clinical principle is:

HYPOCALCAEMIA THAT DOES NOT CORRECT APPROPRIATELY → CHECK MAGNESIUM.

If magnesium is severely deficient, calcium may remain low despite calcium replacement until:

Magnesium is corrected.

Hypomagnesaemia may also coexist with:

Hypokalaemia.

19. Sepsis

The original notes correctly include:

Sepsis.

Hypocalcaemia is relatively common in severe critical illness and may result from multiple mechanisms, including altered:

PTH responsiveness.

Vitamin D metabolism.

Calcium distribution.

Renal function.

Inflammatory signalling.

The presence of hypocalcaemia in severe sepsis therefore does not necessarily indicate a primary parathyroid disorder.

20. Respiratory Alkalosis

The original notes correctly identify:

Respiratory alkalosis.

However, this requires an important distinction.

Respiratory alkalosis may reduce:

Ionised calcium

without substantially reducing total body calcium.

21. Mechanism in Alkalosis

When blood pH rises:

Albumin becomes more negatively charged.

Therefore albumin binds more:

Ca²⁺.

This reduces the concentration of:

Free ionised calcium.

Therefore:

ALKALOSIS

↓

↑ Calcium binding to albumin

↓

↓ Ionised Ca²⁺

↓

Increased neuromuscular excitability.

22. Hyperventilation and Tetany

This explains why a person who is hyperventilating can develop:

Perioral tingling.

Paraesthesia.

Carpopedal spasm.

Tetany.

The mechanism is:

Hyperventilation

↓

↓ PaCO₂

↓

Respiratory alkalosis

↓

↑ Albumin binding of calcium

↓

↓ Ionised Ca²⁺

↓

Neuromuscular symptoms.

This may occur even when:

Total serum calcium is normal.

23. Acute Pancreatitis

The original notes correctly identify:

Acute pancreatitis.

Severe acute pancreatitis can be associated with:

Hypocalcaemia.

One traditional mechanism involves fat necrosis.

24. Fat Saponification

Pancreatic enzymes damage surrounding fat, releasing:

Free fatty acids.

These can bind calcium and form insoluble:

Calcium soaps.

This process is called:

Saponification.

Therefore:

PANCREATITIS → FAT NECROSIS → CALCIUM SOAP FORMATION → HYPOCALCAEMIA.

In severe pancreatitis, additional mechanisms may also contribute.

25. Prostate Carcinoma

The original notes include:

Carcinoma of the prostate.

This is a recognised but much less common cause of hypocalcaemia.

Prostate cancer classically produces:

Osteoblastic bone metastases.

These metastases promote deposition of mineral into newly forming bone.

In extensive osteoblastic disease, calcium can be taken up from the circulation into bone.

Therefore:

Extensive osteoblastic metastases → increased skeletal calcium uptake → hypocalcaemia.

26. Osteoblastic Metastases

This mechanism is particularly associated with malignancies producing extensive:

Osteoblastic skeletal metastases.

Prostate cancer is the classic example.

This is different from many osteolytic malignancies, which are more likely to cause:

Hypercalcaemia.

Therefore:

PROSTATE CANCER → OSTEOBLASTIC METASTASES → occasionally HYPOCALCAEMIA.

27. Massive Blood Transfusion – Important Additional Cause

An important additional cause is:

Massive blood transfusion.

Stored blood products contain:

Citrate.

Citrate binds circulating:

Ionised calcium.

Therefore rapid administration of large quantities of blood products can cause:

Acute hypocalcaemia.

This is particularly important during:

Massive transfusion protocols.

28. Other Important Causes

Other causes that may need consideration include:

Malabsorption.

Severe phosphate loading.

Certain medications.

Hungry bone syndrome after parathyroidectomy.

Tumour lysis syndrome.

Critical illness.

The clinical context usually helps identify the mechanism.

29. Hungry Bone Syndrome

After successful treatment of severe hyperparathyroidism, high-turnover bone can rapidly take up:

Calcium.

Phosphate.

Magnesium.

This produces:

Hungry bone syndrome.

Therefore prolonged hypocalcaemia after parathyroidectomy is not always caused simply by:

Hypoparathyroidism.

30. Clinical Features

The clinical manifestations of hypocalcaemia are largely caused by increased:

Neuromuscular excitability.

Symptoms depend not only on the absolute calcium concentration but also on:

How rapidly calcium falls.

An acute fall can produce severe symptoms even at a calcium concentration that might be tolerated in chronic disease.

31. Paraesthesia

Early symptoms commonly include:

Perioral tingling.

Tingling of the fingers and toes.

Paraesthesia.

These are important clues to increased:

Neuromuscular excitability.

32. Muscle Symptoms

The original notes include:

Muscle weakness.

Patients may experience:

Muscle cramps.

Spasms.

Weakness.

However, the most characteristic acute manifestation is increased neuromuscular excitability rather than isolated weakness.

33. Tetany

The original notes correctly identify:

Tetany.

Tetany results from increased excitability of peripheral nerves and muscles.

Manifestations can include:

Carpopedal spasm.

Muscle cramps.

Facial twitching.

Laryngospasm.

Severe tetany can become a medical emergency.

34. Trousseau Sign

Trousseau sign is an important sign of latent tetany.

A blood-pressure cuff is inflated above systolic pressure for several minutes.

In hypocalcaemia this can precipitate:

Carpal spasm.

This reflects increased:

Neuromuscular excitability.

35. Chvostek Sign

Chvostek sign is facial muscle contraction following tapping over the:

Facial nerve.

It may occur in hypocalcaemia.

However, it is less specific because it can occasionally occur in individuals without clinically significant hypocalcaemia.

36. Seizures

The original notes correctly include:

Seizures.

Severe hypocalcaemia increases neuronal excitability and may cause:

Generalised seizures.

Hypocalcaemia should therefore be considered among metabolic causes of a new seizure, particularly when accompanied by:

Tetany or paraesthesia.

37. Confusion

The original notes correctly include:

Confusion.

Neurological manifestations can range from:

Irritability and confusion

to:

Seizures

and, in severe cases:

Altered consciousness.

38. Laryngospasm

Severe neuromuscular excitability can involve the laryngeal muscles.

This can cause:

Laryngospasm.

Although uncommon, it is potentially:

Life-threatening.

39. Cardiac Manifestations

Hypocalcaemia affects cardiac repolarisation.

The classic ECG abnormality is:

Prolongation of the QT interval, largely through prolongation of the ST segment.

Severe abnormalities may predispose to:

Arrhythmias.

40. Cataracts

The original notes correctly include:

Cataracts.

Cataracts are particularly associated with:

Chronic hypocalcaemia, especially longstanding hypoparathyroidism.

They are therefore more characteristic of chronic disease than an acute fall in calcium.

41. Dental Hypoplasia

The original notes correctly include:

Dental hypoplasia.

Longstanding hypocalcaemia during periods of tooth development can interfere with:

Dental mineralisation and enamel formation.

Dental abnormalities are therefore particularly relevant when hypoparathyroidism or hypocalcaemia begins during:

Childhood.

42. Intracranial Calcification

Chronic hypoparathyroidism can also produce:

Basal ganglia and other intracranial calcification.

This is related to longstanding abnormalities of:

Calcium-phosphate metabolism.

It is particularly associated with chronic:

Hypoparathyroidism or pseudohypoparathyroidism.

43. Diagnosis

The first step is to confirm that the patient has genuine:

Hypocalcaemia.

This can involve:

Albumin-adjusted total calcium

or direct measurement of:

Ionised calcium.

Ionised calcium is particularly useful when albumin or acid-base status is substantially abnormal.

44. Finding the Cause

Once true hypocalcaemia is confirmed, useful investigations commonly include:

PTH.

Phosphate.

Magnesium.

Renal function.

25-hydroxyvitamin D.

ALP.

The pattern of these results often identifies the underlying mechanism.

45. PTH Is a Key Test

PTH is particularly useful because it separates hypocalcaemia into two broad patterns.

If calcium is low and:

PTH is low or inappropriately normal

think:

Hypoparathyroidism.

If calcium is low and:

PTH is appropriately elevated

think about causes such as:

Vitamin D deficiency, CKD, malabsorption or other secondary causes.

46. Important Biochemical Patterns

HYPOPARATHYROIDISM

Ca²⁺:

↓

Phosphate:

↑

PTH:

↓

VITAMIN D DEFICIENCY

Ca²⁺:

↓ or low-normal

Phosphate:

↓

PTH:

↑

ALP:

↑

25(OH)D:

↓

ADVANCED CKD

Ca²⁺:

↓ or normal

Phosphate:

↑

PTH:

↑

Calcitriol:

↓

SEVERE HYPOMAGNESAEMIA

Ca²⁺:

↓

Mg²⁺:

↓

PTH:

May be low/inappropriately normal or functionally ineffective.

47. Treatment Principles

The original notes state:

Calcium + vitamin D supplementation.

This is correct for many chronic causes, but treatment depends strongly on:

Severity and underlying cause.

Acute severe symptomatic hypocalcaemia requires a different approach from mild chronic hypocalcaemia.

48. Acute Severe Hypocalcaemia

Severe symptomatic hypocalcaemia may require:

Intravenous calcium, commonly calcium gluconate, with appropriate monitoring.

This is particularly important when there is:

Tetany.

Seizures.

Laryngospasm.

Significant QT prolongation or other cardiac manifestations.

49. Chronic Treatment

Chronic hypocalcaemia may require:

Oral calcium supplementation

and:

Vitamin D therapy.

The appropriate form of vitamin D depends on the cause.

For example, in chronic hypoparathyroidism, treatment often requires an:

Active vitamin D preparation such as calcitriol, because PTH-dependent renal activation of vitamin D is reduced.

50. Correct Magnesium

If the patient has:

Hypomagnesaemia,

magnesium must also be corrected.

Otherwise:

PTH secretion and action remain impaired

and hypocalcaemia may remain:

Refractory.

Therefore:

LOW Ca²⁺ + LOW Mg²⁺ → REPLACE Mg²⁺ AS WELL.

51. Treat Vitamin D Deficiency

When hypocalcaemia is caused by vitamin D deficiency:

Vitamin D should be replaced

and adequate:

Calcium intake

should be ensured.

The underlying cause of vitamin D deficiency, such as:

Malabsorption or inadequate intake/exposure,

should also be addressed.

52. Treat the Underlying Cause

Specific treatment may therefore involve:

Vitamin D replacement for deficiency.

Magnesium replacement for hypomagnesaemia.

Management of CKD-MBD in chronic kidney disease.

Treatment of acute pancreatitis or sepsis.

Correction of severe hyperphosphataemia.

Appropriate treatment of hypoparathyroidism.

53. Causes of Hypocalcaemia – Note Form

LOW PTH

Hypoparathyroidism.

Post-thyroid/parathyroid surgery.

Autoimmune hypoparathyroidism.

DiGeorge syndrome.

VITAMIN D PROBLEMS

Vitamin D deficiency.

Malabsorption.

Reduced calcitriol production in advanced CKD.

RENAL/MINERAL DISORDERS

Advanced CKD.

Hyperphosphataemia.

MAGNESIUM DEFICIENCY

Severe hypomagnesaemia causes:

↓ PTH secretion + PTH resistance.

CALCIUM BINDING OR DEPOSITION

Acute pancreatitis.

Massive transfusion due to citrate.

Marked hyperphosphataemia.

REDUCED IONISED CALCIUM

Respiratory alkalosis.

CRITICAL ILLNESS

Sepsis.

OSTEOBLASTIC UPTAKE

Extensive osteoblastic metastases, classically:

Prostate carcinoma.

Hungry bone syndrome after treatment of severe hyperparathyroidism.

54. Clinical Features – Note Form

NEUROMUSCULAR

Perioral tingling.

Paraesthesia.

Muscle cramps.

Carpopedal spasm.

Tetany.

Muscle weakness.

Chvostek sign.

Trousseau sign.

Laryngospasm in severe cases.

NEUROLOGICAL

Confusion.

Irritability.

Seizures.

Altered consciousness in severe disease.

CARDIAC

Prolonged QT interval.

Potential arrhythmias in severe hypocalcaemia.

CHRONIC FEATURES

Cataracts.

Dental abnormalities/hypoplasia.

Intracranial calcification, particularly with chronic hypoparathyroidism.

55. Important Clarifications to the Original Notes

The original:

“Low levels of vitamin D3”

is better expressed as:

Vitamin D deficiency or impaired vitamin D metabolism.

For assessing vitamin D stores, the usual measurement is:

25-hydroxyvitamin D – 25(OH)D.

The original:

“Respiratory alkalosis”

is correct, but the main effect is a reduction in:

IONISED CALCIUM.

The mechanism is:

↑ pH → ↑ calcium binding to albumin → ↓ free Ca²⁺.

The original:

“Calcium deposition – acute pancreatitis”

is also correct as traditional teaching.

Remember:

FAT NECROSIS → SAPONIFICATION → CALCIUM SOAP FORMATION → HYPOCALCAEMIA, although severe pancreatitis-associated hypocalcaemia can be multifactorial.

The original:

“Carcinoma of prostate”

refers particularly to:

Extensive osteoblastic bone metastases, which can increase calcium uptake into bone.

This is much less common than hypocalcaemia caused by vitamin D deficiency, CKD or hypoparathyroidism.

The original treatment:

“Calcium + vitamin D3”

needs to be adapted to the cause.

Severe symptomatic hypocalcaemia → IV calcium.

Chronic/mild disease → oral calcium ± appropriate vitamin D.

Hypomagnesaemia → correct magnesium.

Hypoparathyroidism → calcium + active vitamin D such as calcitriol is commonly used.

Key Clinical Pattern

For rapid recall:

HYPOCALCAEMIA → INCREASED NEUROMUSCULAR EXCITABILITY.

Therefore think:

PERIORAL TINGLING → PARAESTHESIA → CRAMPS → CARPOPEDAL SPASM → TETANY → SEIZURES.

The classic ECG finding is:

PROLONGED QT INTERVAL.

The major biochemical patterns are:

↓ Ca + ↑ phosphate + ↓ PTH → HYPOPARATHYROIDISM.

↓/LOW-NORMAL Ca + ↓ phosphate + ↑ PTH + ↑ ALP → VITAMIN D DEFICIENCY.

↓/NORMAL Ca + ↑ phosphate + ↑ PTH + CKD → SECONDARY HYPERPARATHYROIDISM OF CKD.

↓ Ca + ↓ Mg → CONSIDER MAGNESIUM-RELATED PTH IMPAIRMENT.

And the highest-yield causes to remember are:

HYPOPARATHYROIDISM + VITAMIN D DEFICIENCY + ADVANCED CKD + HYPOMAGNESAEMIA + HYPERPHOSPHATAEMIA + ACUTE PANCREATITIS + SEPSIS + ALKALOSIS.

Ophthalmology – Sympathetic Ophthalmia

What the Disease Represents

Sympathetic ophthalmia (SO) is a rare, bilateral, diffuse granulomatous panuveitis that develops after:

• Penetrating ocular trauma
• Intraocular surgery
• Occasionally other procedures that disrupt the uveal tissues

The injured or operated eye is traditionally called the:

Exciting/inciting eye

and the fellow eye is called the:

Sympathizing eye

Although only one eye is initially injured, the subsequent autoimmune inflammation typically affects:

Both eyes.

⸻

Why the Fellow Eye Becomes Inflamed

The leading mechanism is an autoimmune response to previously sequestered ocular antigens released after disruption of the:

• Uvea
• Retina
• Choroid

This produces:

T-cell-mediated immune attack against melanocyte- and retinal-associated antigens

in both eyes.

⸻

How Rare It Is

Sympathetic ophthalmia is:

Very uncommon

even after severe penetrating trauma or intraocular surgery.

The risk is higher after:

• Open-globe injury
• Repeated intraocular surgery
• Extensive uveal manipulation

but remains low overall.

⸻

When It Can Appear

SO can begin:

• Within days
• Within weeks
• Within months
• Years or even decades after the inciting injury

Most cases occur relatively early after trauma, but:

A very remote history of ocular injury does not exclude the diagnosis.

⸻

Important Clinical Trigger

Always ask about:

• Previous open-globe trauma
• Ocular surgery
• Multiple retinal procedures
• Previous removal or repair of a severely injured eye

A history of ocular penetration in a patient with bilateral granulomatous panuveitis should immediately raise suspicion for:

Sympathetic ophthalmia.

⸻

What the Patient Usually Notices

Symptoms may include:

• Blurred vision
• Photophobia
• Ocular pain
• Redness
• Floaters
• Metamorphopsia

The fellow eye may initially develop subtle symptoms before severe inflammation becomes apparent.

⸻

What the Anterior Segment Can Show

Typical findings include:

• Granulomatous keratic precipitates
• Anterior chamber cells and flare
• Posterior synechiae
• Iris thickening
• Ciliary injection

The degree of anterior inflammation varies.

⸻

Vitreous Involvement

Vitreous inflammation may include:

• Cells
• Haze

This contributes to the classification as:

Panuveitis

rather than isolated choroiditis.

⸻

Characteristic Posterior Segment Findings

Posterior manifestations may include:

• Multifocal serous retinal detachments
• Diffuse choroidal thickening
• Optic disc edema
• Choroidal infiltrates
• Dalen–Fuchs nodules
• Retinal edema

These findings can closely resemble:

Vogt–Koyanagi–Harada disease.

⸻

Dalen–Fuchs Nodules

Dalen–Fuchs nodules are small yellow-white lesions located at the level of:

• RPE
• Bruch membrane

They correspond histologically to collections of epithelioid cells beneath the RPE.

They are characteristic but:

Not pathognomonic

and may also be seen in VKH.

⸻

Serous Retinal Detachment

One of the most important vision-threatening findings is:

Exudative retinal detachment

caused by severe choroidal inflammation and breakdown of the outer blood-retinal barrier.

OCT is particularly useful for documenting:

• Subretinal fluid
• RPE undulations
• Choroidal thickening

⸻

Histopathologic Pattern

Classic pathology shows:

• Diffuse granulomatous choroiditis
• Lymphocytes, predominantly T cells
• Epithelioid histiocytes
• Multinucleated giant cells

The choriocapillaris is often relatively spared early.

Dalen–Fuchs nodules may be present between:

• RPE
• Bruch membrane

⸻

How the Diagnosis Is Made

There is:

No single confirmatory blood test

Diagnosis is based on:

1. Compatible bilateral granulomatous uveitis
2. History of prior penetrating ocular trauma or surgery
3. Characteristic multimodal imaging
4. Exclusion of important mimics

⸻

Optical Coherence Tomography

OCT may demonstrate:

• Multifocal subretinal fluid
• RPE folds
• Septa within serous detachments
• Outer retinal disruption
• Choroidal thickening on enhanced-depth imaging

Serial OCT is valuable for monitoring treatment response.

⸻

Fluorescein Angiography

FA classically shows:

• Multiple pinpoint areas of early hyperfluorescence
• Progressive leakage
• Pooling beneath areas of serous retinal detachment
• Optic disc leakage

This pattern strongly resembles VKH.

⸻

Indocyanine Green Angiography

ICGA may show:

• Multiple hypofluorescent dark dots
• Delayed choroidal perfusion
• Diffuse choroidal inflammatory abnormalities

ICGA can reveal disease activity not obvious clinically.

⸻

Fundus Autofluorescence

FAF may demonstrate:

• Hyperautofluorescent areas of active RPE stress
• Hypoautofluorescent areas of established RPE atrophy

It is useful for documenting:

Chronic RPE damage.

⸻

B-Scan Ultrasonography

B-scan may demonstrate:

• Choroidal thickening
• Serous retinal detachment

It is particularly useful when:

• Media opacity limits fundus visualization

⸻

Important Diagnostic Mimics

The major differential diagnoses include:

• Vogt–Koyanagi–Harada disease
• Sarcoidosis
• Tuberculosis
• Syphilis
• Posterior scleritis
• Primary vitreoretinal lymphoma
• Other granulomatous panuveitides

⸻

Distinguishing SO From VKH

Sympathetic Ophthalmia

• Prior ocular trauma or surgery
• Bilateral granulomatous panuveitis
• Dalen–Fuchs nodules
• Serous retinal detachments

Vogt–Koyanagi–Harada Disease

• No preceding penetrating ocular injury
• May have neurologic/auditory symptoms
• May develop:
• Vitiligo
• Poliosis
• Alopecia

The ocular appearance can be nearly identical.

⸻

Infectious Disease Must Be Excluded

Before major immunosuppression, evaluate for important mimics such as:

• Tuberculosis
• Syphilis

and other infections when clinically indicated.

This is especially important before:

• Biologic therapy
• Long-term systemic immunosuppression

⸻

HLA Associations

Various HLA associations have been reported, including:

• HLA-DR4-related alleles

However:

HLA testing has no routine diagnostic role.

⸻

Immediate Treatment Goal

The central objective is:

Rapid and sustained suppression of intraocular inflammation before irreversible retinal, choroidal, and optic nerve damage develops.

Treatment should generally be:

Aggressive from the outset.

⸻

First-Line Systemic Treatment

Acute disease is usually treated with:

High-dose systemic corticosteroids

such as oral prednisone, often around:

1 mg/kg/day

depending on severity.

Severe disease may require:

IV methylprednisolone pulse therapy

for rapid control.

⸻

Why a Slow Steroid Taper Matters

Inflammation may recur when corticosteroids are tapered too quickly.

Therefore tapering is usually:

Slow and guided by clinical and imaging evidence of quiescence.

OCT and angiography can detect persistent posterior inflammation even when symptoms improve.

⸻

Early Steroid-Sparing Therapy

Modern management often favors:

Early introduction of immunomodulatory therapy

rather than relying on prolonged high-dose corticosteroids alone.

This reduces:

• Steroid toxicity
• Recurrence
• Chronic inflammation

⸻

Common Immunomodulatory Agents

Options include:

• Mycophenolate mofetil
• Methotrexate
• Azathioprine
• Cyclosporine
• Tacrolimus

Choice depends on:

• Disease severity
• Comorbidities
• Patient age
• Specialist experience

⸻

Biologic Therapy

Refractory or severe disease may respond to:

• Adalimumab
• Infliximab

Other biologic agents may be used in selected cases.

These generally require:

• TB screening
• Hepatitis screening
• Multidisciplinary monitoring

⸻

Local Steroid Therapy

Periocular or intravitreal corticosteroid can be useful as an adjunct for:

• Persistent macular edema
• Asymmetric inflammation

However:

Local treatment alone is usually inadequate for a bilateral systemic autoimmune process such as SO.

⸻

Role of Steroid Implants

Long-acting intravitreal corticosteroid implants may control inflammation in selected cases but carry risks including:

• Cataract
• Ocular hypertension
• Glaucoma

They are not a universal substitute for systemic immunomodulation.

⸻

The Old “14-Day Enucleation Rule”

Traditional teaching stated that a blind traumatized eye should be enucleated within:

14 days

to prevent sympathetic ophthalmia.

This rule is now considered:

Oversimplified and not strongly evidence-based.

Because SO is rare and visual potential may be difficult to judge immediately after trauma, prophylactic removal should not be automatic.

⸻

When Enucleation May Still Be Considered

Early enucleation may be considered when an injured eye is:

• Irreversibly blind
• Severely disorganized
• Painful
• Without realistic visual potential

The decision should balance:

• Possibility of visual recovery
• Structural integrity
• Pain
• Risk of infection
• Patient preference

⸻

What to Do Once Sympathetic Ophthalmia Has Started

After SO has developed:

Removal of the exciting eye generally does not reliably improve inflammation or visual outcome in the sympathizing eye.

Therefore an eye with useful or potentially useful vision should not be removed simply because SO has begun.

⸻

Enucleation vs Evisceration

Historically, enucleation was favored over evisceration because retained uveal tissue was thought to increase SO risk.

Modern data suggest the absolute risk after either procedure is:

Extremely low

but enucleation remains the traditional choice when removal of a severely traumatized eye is undertaken specifically in the context of concern about sympathetic ophthalmia.

⸻

Management of Cataract

Chronic inflammation and steroid therapy can cause:

Cataract

Surgery should ideally be performed when inflammation has been:

Well controlled for a sustained period

with appropriate perioperative anti-inflammatory coverage.

⸻

Management of Glaucoma

Glaucoma may result from:

• Chronic uveitis
• Peripheral anterior synechiae
• Corticosteroid therapy

Treatment may require:

• Topical medications
• Laser in selected situations
• Glaucoma surgery

while maintaining adequate inflammatory control.

⸻

Macular Complications

Visual loss may result from:

• Persistent serous retinal detachment
• Cystoid macular edema
• RPE atrophy
• Subretinal fibrosis
• Photoreceptor loss

OCT is central to monitoring these complications.

⸻

Follow-Up During Active Disease

Patients require:

Close and frequent review

with assessment of:

• Visual acuity
• Anterior chamber activity
• Vitreous inflammation
• IOP
• Optic nerve
• OCT
• Choroidal/retinal activity

Severe disease may initially require review:

• Every few days
• Weekly

depending on response.

⸻

Long-Term Monitoring

Even after apparent remission, recurrence can occur.

Long-term follow-up should monitor for:

• Recurrent uveitis
• Cataract
• Glaucoma
• Macular edema
• RPE/choroidal atrophy
• Immunosuppressive drug toxicity

⸻

Expected Visual Outcome

Modern aggressive immunosuppression has greatly improved prognosis.

Many patients can retain:

Useful central vision

if inflammation is treated early and sustained remission is achieved.

Poorer outcomes are associated with:

• Delayed diagnosis
• Recurrent inflammation
• Chronic serous detachment
• Glaucoma
• Macular scarring
• Optic nerve damage

⸻

Major Ocular Complications

Potential complications include:

• Bilateral visual loss
• Cataract
• Secondary glaucoma
• Cystoid macular edema
• Serous retinal detachment
• Subretinal fibrosis
• RPE atrophy
• Chorioretinal scarring
• Optic nerve damage

⸻

High-Yield Takeaways

• Sympathetic ophthalmia is a rare bilateral granulomatous panuveitis occurring after penetrating ocular trauma or intraocular surgery.
• The injured eye is the exciting/inciting eye, and the fellow eye is the sympathizing eye.
• The disease is thought to result from T-cell-mediated autoimmunity against previously sequestered ocular antigens.
• SO can occur days to decades after ocular injury, so even remote trauma is relevant.
• Classic posterior findings include multifocal serous retinal detachments, diffuse choroidal thickening, optic disc edema, and Dalen–Fuchs nodules.
• Dalen–Fuchs nodules are characteristic but not pathognomonic and may also occur in VKH.
• FA typically shows multiple pinpoint leaks with late pooling beneath serous detachments.
• OCT is essential for monitoring subretinal fluid, outer retinal injury, and choroidal thickening.
• The main clinical mimic is Vogt–Koyanagi–Harada disease; the key discriminator is a history of ocular trauma or surgery.
• Tuberculosis, syphilis, sarcoidosis, and other granulomatous disorders should be excluded when appropriate.
• Treatment requires prompt high-dose systemic corticosteroids.
• Because recurrence is common and long-term steroid toxicity is substantial, modern care often uses early steroid-sparing immunomodulatory therapy.
• Mycophenolate, methotrexate, azathioprine, cyclosporine, tacrolimus, and biologics such as adalimumab or infliximab may be used depending on severity.
• The traditional rule that a blind traumatized eye must be enucleated within 14 days is not supported as an absolute modern standard.
• Once SO has developed, removing the exciting eye does not reliably improve the fellow eye and should not be done solely for that purpose when the eye has useful visual potential.
• Long-term prognosis is substantially better with early aggressive control of inflammation and sustained immunomodulation.

Ophthalmology – Superior Limbic Keratoconjunctivitis

What the Disorder Represents

Superior limbic keratoconjunctivitis (SLK) is a chronic, recurrent ocular-surface disorder involving the:

• Superior bulbar conjunctiva
• Superior limbus
• Superior corneal epithelium
• Superior tarsal conjunctiva

It is usually:

• Bilateral
• Often asymmetric
• More common in middle-aged women

Typical symptoms include:

• Foreign-body sensation
• Burning
• Photophobia
• Ocular discomfort
• Fluctuating vision

Symptoms may appear disproportionately severe relative to the initial examination.

The Classic Clinical Pattern

The characteristic constellation includes:

• Superior bulbar conjunctival injection
• Redundant or lax superior bulbar conjunctiva
• Marked superior conjunctival staining
• Fine papillary reaction of the superior tarsal conjunctiva
• Superior punctate epithelial keratopathy
• Mucus strands or corneal filaments

This superior distribution is one of the most useful diagnostic clues.

Who Is Most Often Affected

SLK most commonly occurs in:

• Middle-aged adults
• Women more often than men

It can occur at other ages, especially when associated with:

• Thyroid eye disease
• Severe dry eye disease
• Contact lens-related mechanical irritation

Strongest Systemic Association

The classic association is:

Thyroid disease, particularly Graves disease/thyroid eye disease

A substantial proportion of patients with SLK have:

• Current thyroid disease
• Previous thyroid disease
• Clinical signs of thyroid eye disease

Therefore thyroid history should always be reviewed.

Why Thyroid Eye Disease Promotes SLK

Thyroid eye disease can produce:

• Upper-lid retraction
• Tight upper eyelid
• Proptosis
• Increased blink friction
• Exposure
• Tear-film instability

These factors increase mechanical interaction between the:

Upper lid and superior bulbar conjunctiva

and may contribute to development of SLK.

Other Important Associations

SLK is also associated with:

• Aqueous-deficient dry eye
• Meibomian gland dysfunction
• Filamentary keratitis
• Superior conjunctivochalasis
• Chronic contact lens wear

Older reports also described associations with:

• Thimerosal-containing contact lens solutions

which are now much less relevant because thimerosal is rarely used in modern contact lens care.

How the Disease Probably Develops

The exact mechanism is not fully established.

The leading model is:

Mechanical microtrauma + tear-film deficiency + chronic ocular-surface inflammation

Repeated friction occurs between:

• Tight superior eyelid
• Redundant superior bulbar conjunctiva
• Superior limbus

This produces:

• Epithelial injury
• Abnormal conjunctival keratinization
• Inflammation
• Mucus production

Role of Conjunctivochalasis

Some patients have excessive mobility or redundancy of the superior bulbar conjunctiva.

The loose conjunctiva is repeatedly dragged across the:

Superior cornea and limbus during blinking

which may perpetuate inflammation.

This mechanical component explains why procedures that:

• Resect
• Tighten
• Cauterize

the superior conjunctiva can improve refractory disease.

Typical Symptoms

Patients commonly describe:

• Grittiness
• Foreign-body sensation
• Burning
• Photophobia
• Tearing
• Ocular pain or discomfort
• Intermittent blurred vision

Symptoms usually fluctuate with:

• Dry environments
• Prolonged visual activity
• Exacerbation of dry eye

Why Pain May Seem Disproportionate

Surface disease may be localized to a relatively small superior area but remain highly symptomatic because:

• The superior lid repeatedly rubs the inflamed tissue
• Corneal epithelial defects are painful
• Filaments can mechanically pull on corneal epithelium

Therefore symptom severity may exceed the apparent extent of disease.

Superior Bulbar Conjunctival Findings

The hallmark finding is:

Localized superior bulbar conjunctival inflammation

typically from approximately:

• 10 to 2 o’clock

Findings may include:

• Hyperemia
• Thickening
• Redundancy
• Loss of normal smooth surface
• Lissamine green staining

Superior Tarsal Conjunctival Findings

Upper-lid eversion may reveal:

Fine, velvety papillary hypertrophy

of the superior palpebral conjunctiva.

This is generally finer than the giant papillae seen with:

• Giant papillary conjunctivitis
• Vernal keratoconjunctivitis

Corneal Findings

Corneal involvement typically affects the:

Superior cornea

and may include:

• Punctate epithelial erosions
• Superior epithelial keratitis
• Mucus adherence
• Filamentary keratitis

Severe disease can produce significant discomfort and fluctuating vision.

Filamentary Keratitis

Filaments consist of:

• Mucus
• Degenerated epithelial cells

adhering to compromised corneal epithelium.

They may cause:

• Sharp pain
• Foreign-body sensation
• Photophobia

Mechanical removal can provide temporary relief but does not address the underlying SLK.

Tear-Film Abnormalities

Patients frequently demonstrate:

• Reduced tear meniscus
• Short tear break-up time
• Increased mucus
• Reduced Schirmer values

This reflects frequent coexistence of:

Dry eye disease.

Testing the Mobility of the Superior Conjunctiva

After topical anesthesia, the examiner may gently manipulate the superior bulbar conjunctiva.

In SLK, it may be unusually:

• Mobile
• Redundant

and may be displaced toward the superior cornea more easily than normal.

This supports a mechanical component but is not required for diagnosis.

Ocular Surface Staining

Lissamine green is especially useful for highlighting abnormal superior conjunctival epithelium.

It may show intense staining of the:

• Superior bulbar conjunctiva
• Superior limbal region

Fluorescein is useful for detecting:

• Corneal epithelial disease

Rose bengal can also stain damaged epithelium but is used less often because it causes more discomfort.

Why Lissamine Green Is Preferred

Lissamine green:

• Highlights devitalized or mucin-deficient epithelium
• Is usually better tolerated
• Is particularly useful for documenting the superior conjunctival component

The distribution of staining can be more diagnostically useful than total staining severity.

Schirmer Testing

Schirmer testing may be useful when aqueous-deficient dry eye is suspected.

A reduced result supports coexisting:

Keratoconjunctivitis sicca

but does not itself diagnose SLK.

Thyroid Evaluation

Patients without a known thyroid disorder should be assessed for symptoms or signs such as:

• Weight change
• Heat intolerance
• Palpitations
• Tremor
• Lid retraction
• Proptosis

Laboratory evaluation may include:

• TSH
• Free T4

with further thyroid testing guided by clinical findings.

Routine parathyroid testing is not standard in modern evaluation unless there is another clinical indication.

What Pathology Shows

Histopathology may demonstrate:

• Squamous metaplasia
• Keratinization of conjunctival epithelium
• Inflammatory cell infiltration
• Goblet-cell abnormalities

These changes support chronic epithelial trauma and inflammation.

Biopsy is:

Not usually necessary for diagnosis.

Conditions That Can Mimic SLK

Important differentials include:

• Dry eye disease
• Filamentary keratitis
• Allergic conjunctivitis
• Giant papillary conjunctivitis
• Vernal keratoconjunctivitis
• Atopic keratoconjunctivitis
• Contact lens-related disease
• Conjunctivochalasis
• Toxic medicamentosa
• Mucus fishing syndrome

Distinguishing It From Giant Papillary Conjunctivitis

SLK

• Superior bulbar conjunctival staining
• Superior limbal involvement
• Fine papillary tarsal reaction
• Often associated with dry eye or thyroid disease

GPC

• Large papillae on upper tarsal conjunctiva
• Often associated with contact lenses or exposed sutures
• Mucous discharge and lens intolerance are prominent

Distinguishing It From Vernal Keratoconjunctivitis

Vernal disease more commonly features:

• Younger patients
• Severe itching
• Giant cobblestone papillae
• Limbal Horner-Trantas dots
• Seasonal exacerbation

SLK more often affects:

Middle-aged adults with superior bulbar conjunctival disease and mechanical friction.

First Treatment Priority

Management should begin by treating contributing ocular-surface disease.

Common first steps include:

• Preservative-free artificial tears
• Lubricating gel or ointment
• Management of meibomian gland dysfunction
• Reduction of toxic topical medications
• Modification or discontinuation of contact lens wear when contributory

Treating Coexisting Dry Eye

Dry eye management may include:

• Frequent preservative-free tears
• Nighttime ointment
• Warm compresses
• Lid hygiene
• Environmental modification
• Moisture-chamber glasses

Improving the tear film can substantially reduce:

Friction and epithelial injury.

Anti-Inflammatory Eye Drops

A short course of:

Topical corticosteroid

may be useful for significant inflammatory flares.

Because repeated steroid treatment can cause:

• Ocular hypertension
• Glaucoma
• Cataract

IOP should be monitored when treatment is prolonged or recurrent.

Steroid-Sparing Surface Therapy

Longer-term inflammatory control may include:

• Topical cyclosporine
• Lifitegrast in selected patients
• Other dry-eye anti-inflammatory agents

These are particularly useful when significant dry eye coexists.

Filament Management

Filamentary keratitis may be treated with:

• Intensive lubrication
• Mechanical filament removal
• Topical N-acetylcysteine in selected cases
• Bandage contact lens when appropriate

Recurrence is common unless the underlying ocular-surface disease is controlled.

Role of Autologous Serum Tears

For severe refractory surface disease, autologous serum tears can provide:

• Epitheliotrophic growth factors
• Improved lubrication
• Better epithelial healing

They may be particularly useful when significant dry eye coexists with SLK.

Punctal Occlusion

Punctal plugs or cautery may help patients with substantial:

Aqueous tear deficiency

but significant surface inflammation should generally be controlled first.

Therapeutic Contact Lenses

A:

• Bandage soft contact lens
• Scleral lens

may reduce friction and improve symptoms in selected cases.

However, contact lens-associated mechanical irritation can also worsen SLK in some patients, so treatment must be individualized.

Silver Nitrate – Historical Perspective

Older treatment protocols frequently used:

0.5–1% silver nitrate

applied to the superior conjunctiva.

This can chemically cauterize abnormal epithelium and occasionally relieve symptoms.

However, silver nitrate is now used much less frequently because of the risk of:

• Chemical injury
• Corneal toxicity
• Scleral injury

and because safer medical and surgical options are available.

Important Silver Nitrate Safety Point

If silver nitrate is used by an experienced clinician:

Solid silver nitrate sticks should never be applied directly to the ocular surface.

They can produce severe chemical burns.

When Surgery Is Considered

Surgery is appropriate when:

• Symptoms remain severe
• Medical therapy fails
• Redundant superior conjunctiva is prominent
• Mechanical friction is clearly contributing

Superior Conjunctival Resection

One of the most effective surgical approaches is:

Resection of redundant superior bulbar conjunctiva

often with removal of adjacent:

Tenon tissue

The goal is to reduce:

• Conjunctival redundancy
• Superior friction
• Recurrent epithelial trauma

Conjunctival Resection With Tenonectomy

Removing both redundant conjunctiva and abnormal underlying Tenon tissue may reduce recurrence.

Treatment typically involves the superior region spanning roughly:

10 to 2 o’clock

although the extent is individualized.

Conjunctival Cauterization

Thermocautery or other controlled conjunctival cautery can:

• Tighten redundant tissue
• Reduce mobility
• Decrease mechanical trauma

It can be effective in appropriately selected patients.

Why Mechanical Procedures Work

Surgical and cautery procedures do not primarily suppress inflammation.

Instead they address the mechanical cycle:

Redundant conjunctiva → lid friction → epithelial injury → inflammation

by physically reducing conjunctival redundancy.

Supratarsal Steroid Injection

Supratarsal corticosteroid injection has been reported to improve refractory SLK.

However, it is not a routine first-line treatment because it can cause:

• IOP elevation
• Steroid response
• Other injection-related complications

It should be reserved for selected cases under specialist supervision.

Relationship to Thyroid Treatment

Treating systemic thyroid dysfunction is important for overall health.

However:

Correction of thyroid hormone levels alone does not necessarily eliminate SLK

because associated mechanical abnormalities such as:

• Lid retraction
• Proptosis
• Tight upper eyelid

may persist.

When Eyelid Surgery May Matter

In patients with significant thyroid eye disease and upper-lid retraction, correction of eyelid position may reduce:

• Exposure
• Mechanical friction

and can sometimes improve recurrent ocular-surface disease.

Follow-Up Approach

Follow-up depends on severity.

Monitor:

• Symptoms
• Superior conjunctival staining
• Corneal staining
• Filaments
• Tear-film status
• IOP if corticosteroids are used

Stable mild disease may be reviewed periodically, while severe epithelial disease requires closer observation.

Expected Clinical Course

SLK is usually:

Chronic and relapsing

Patients may experience:

• Exacerbations
• Partial remissions
• Long symptom-free intervals

Some cases improve spontaneously over time.

Visual Prognosis

The visual prognosis is generally:

Excellent

because SLK usually does not cause permanent intraocular damage.

Vision may fluctuate due to:

• Tear-film instability
• Corneal epithelial disease

Severe permanent visual loss is uncommon.

Problems That Can Develop

Potential complications include:

• Filamentary keratitis
• Persistent corneal epithelial defects
• Severe dry-eye symptoms
• Contact lens intolerance
• Steroid-induced ocular hypertension from treatment
• Rare chronic corneal surface damage

High-Yield Takeaways

• Superior limbic keratoconjunctivitis is a chronic inflammatory and mechanical disorder of the superior ocular surface.
• The classic pattern is superior bulbar conjunctival injection/staining + redundant superior conjunctiva + fine superior tarsal papillae + superior punctate keratitis or filaments.
• SLK is usually bilateral but asymmetric and occurs most often in middle-aged women.
• The strongest systemic association is thyroid disease, particularly thyroid eye disease.
• Mechanical friction between a tight upper lid and redundant superior bulbar conjunctiva is thought to be central to pathogenesis.
• Coexisting aqueous-deficient dry eye and meibomian gland dysfunction are common and should be actively treated.
• Lissamine green staining of the superior bulbar conjunctiva is particularly useful diagnostically.
• Fine superior tarsal papillae differ from the giant papillae of GPC or vernal keratoconjunctivitis.
• Initial treatment emphasizes preservative-free lubrication and management of associated dry eye.
• Short courses of topical corticosteroid can control inflammatory flares, while cyclosporine or other steroid-sparing dry-eye agents may be useful for chronic disease.
• Filamentary keratitis may require filament removal, intensive lubrication, and N-acetylcysteine in selected cases.
• Silver nitrate is a historical treatment and is used much less often today because of the risk of chemical ocular injury.
• Refractory disease with prominent conjunctival redundancy may respond well to superior conjunctival resection with or without Tenonectomy or controlled cauterization.
• Supratarsal steroid injection is an option in selected cases but requires awareness of steroid-induced IOP elevation.
• The disorder often follows a relapsing-remitting course, but long-term visual prognosis is generally excellent.

Ophthalmology – Subconjunctival Hemorrhage

What the Finding Represents

A subconjunctival hemorrhage (SCH) is extravasation of blood from small conjunctival vessels into the potential space beneath the conjunctiva.

It typically appears as a:

• Sharply demarcated bright-red patch
• Flat or mildly elevated area of blood over the sclera
• Painless red eye with otherwise preserved vision

The blood is trapped beneath the transparent conjunctiva and therefore appears striking despite usually being:

Benign and self-limited.

Why the Eye Looks So Red

Small conjunctival vessels rupture and blood accumulates between the:

• Conjunctiva
• Episcleral surface

Unlike conjunctivitis, there is usually:

• No significant discharge
• No diffuse conjunctival inflammation
• No corneal involvement

Common Clinical Patterns

SCH may be:

• Spontaneous
• Valsalva-related
• Traumatic
• Postoperative
• Recurrent

Most isolated spontaneous cases have no serious underlying disorder.

Common Triggers

Frequent precipitating events include:

• Coughing
• Sneezing
• Vomiting
• Constipation/straining
• Heavy lifting
• Vigorous exercise
• Eye rubbing
• Minor unnoticed trauma

These transiently increase venous pressure and can rupture fragile conjunctival vessels.

Systemic Factors That Increase Risk

Associated conditions include:

• Hypertension
• Diabetes mellitus
• Platelet disorders
• Coagulopathy

Medication-associated risk is increased with:

• Anticoagulants
• Antiplatelet agents

Examples include:

• Warfarin
• Direct oral anticoagulants
• Aspirin
• Clopidogrel

Other Ocular Associations

SCH may occur after:

• Contact lens trauma
• Intravitreal injection
• Cataract or glaucoma surgery
• Conjunctival surgery
• Local anesthetic injection
• Viral conjunctivitis

It can also accompany more substantial ocular trauma.

Typical Symptoms

Most patients simply notice:

A painless red patch on the eye

often discovered:

• In a mirror
• By a family member
• Incidentally

Vision should remain:

Normal.

Minor Associated Sensations

Some patients report:

• Mild foreign-body sensation
• Slight fullness
• Mild irritation

Significant:

• Pain
• Photophobia
• Visual loss

is not typical and should prompt consideration of another or additional diagnosis.

Typical Examination Appearance

The hemorrhage is usually:

• Bright red initially
• Well circumscribed
• Located beneath the conjunctiva
• Nonblanching

The underlying sclera may be completely obscured within the involved area.

How the Appearance Changes During Healing

As the hemorrhage resolves, the color may evolve from:

• Bright red
• Dark red
• Brown
• Yellow

similar to a resolving bruise.

This does not indicate infection.

How Long It Takes to Resolve

Most uncomplicated SCH clears spontaneously within approximately:

1–2 weeks

Larger hemorrhages may require:

2–3 weeks or occasionally longer.

Blood may appear to spread during the first few days because of redistribution beneath the conjunctiva, even though the total hemorrhage is not necessarily increasing.

What Should Be Checked in a Routine Case

For an isolated atraumatic SCH, assess:

• Visual acuity
• External eye
• Cornea
• Anterior chamber

It is also reasonable to check:

Blood pressure

particularly in older adults or patients with recurrent hemorrhage.

When the History Matters More

Ask about:

• Trauma
• Recent surgery
• Coughing or vomiting
• Heavy straining
• Anticoagulant use
• Antiplatelet therapy
• Easy bruising
• Epistaxis
• Gum bleeding
• Previous similar episodes

Recurrent unexplained episodes warrant more investigation than a single typical event.

When Trauma Changes the Situation

A traumatic SCH should not automatically be assumed benign.

A complete ocular examination is necessary to exclude:

• Open-globe injury
• Hyphema
• Corneal or scleral laceration
• Intraocular foreign body
• Orbital injury

A Major Trauma Red Flag

After significant trauma, a:

Bullous, extensive, or 360-degree subconjunctival hemorrhage

can be associated with occult:

Globe rupture.

Particular concern exists when accompanied by:

• Poor vision
• Irregular pupil
• Shallow or abnormally deep anterior chamber
• Low IOP
• Uveal prolapse
• Severe pain

Such cases require urgent ophthalmic assessment.

When Imaging Is Appropriate

Imaging is not needed for routine spontaneous SCH.

In significant ocular/orbital trauma, imaging may include:

CT of the orbits

when evaluating for:

• Fracture
• Intraocular foreign body
• Orbital injury

If open globe is suspected, avoid unnecessary pressure on the eye.

When Laboratory Testing Is Unnecessary

Routine blood testing is generally:

Not required for a single uncomplicated SCH

in an otherwise healthy patient.

When Blood Tests Become Appropriate

Consider investigation when hemorrhages are:

• Recurrent
• Bilateral and unexplained
• Unusually extensive
• Associated with easy bruising or systemic bleeding

Possible tests include:

• CBC with platelet count
• PT/INR
• aPTT

Additional studies should be guided by the clinical history.

Patients Taking Warfarin

For a patient on warfarin with recurrent or unexpectedly large SCH, check:

INR

to ensure anticoagulation is within the intended therapeutic range.

Do Not Stop Anticoagulation Automatically

An isolated SCH is usually not an indication to stop:

• Anticoagulants
• Antiplatelet medications

Discontinuing these agents can expose patients to serious:

• Thromboembolic
• Cardiovascular
• Cerebrovascular

risk.

Any medication adjustment should be coordinated with the prescribing clinician.

Conditions That Can Look Similar

Important alternatives include:

• Conjunctivitis
• Episcleritis
• Scleritis
• Conjunctival vascular lesion
• Traumatic conjunctival laceration

The absence of pain, discharge, photophobia, and visual loss generally favors SCH.

Distinguishing It From Episcleritis

Subconjunctival Hemorrhage

• Sharply demarcated blood
• No visible branching vascular pattern
• Painless
• Nonblanching

Episcleritis

• Dilated superficial vessels
• Mild tenderness possible
• Vessels remain individually visible
• Often partially blanch with phenylephrine

Distinguishing It From Scleritis

Scleritis generally produces:

• Severe deep pain
• Violaceous rather than bright-red color
• Globe tenderness
• Deep vascular congestion

These features are not typical of an uncomplicated SCH.

Treatment in the Usual Case

No specific therapy is required.

Management consists primarily of:

Reassurance and observation.

The blood is gradually resorbed spontaneously.

Relieving Mild Irritation

If mild foreign-body sensation occurs, use:

• Artificial tears
• Lubricating drops

These improve comfort but do not make the hemorrhage disappear faster.

Large or Elevated Hemorrhages

A large elevated or bullous SCH near the limbus can rarely disturb the adjacent tear film and produce:

Corneal dellen

from localized dehydration.

Management may include:

• Frequent lubrication
• Lubricating ointment

and closer ophthalmic observation.

What Not to Do

Routine treatment does not require:

• Antibiotics
• Topical corticosteroids
• Vasoconstrictor drops

These do not accelerate blood resorption.

Follow-Up Needs

An isolated uncomplicated SCH usually requires:

No scheduled ophthalmic follow-up

provided that:

• Vision remains normal
• There is no significant trauma
• Symptoms resolve as expected

When Reassessment Is Appropriate

Review is appropriate if:

• Hemorrhage repeatedly recurs
• It persists unusually long
• It continues enlarging substantially
• Pain develops
• Vision decreases
• Significant ocular trauma occurred

Recurrent Subconjunctival Hemorrhage

Repeated episodes should prompt reassessment for:

• Hypertension
• Anticoagulation
• Platelet disorders
• Coagulopathy
• Recurrent mechanical trauma

Rarely, persistent localized recurrent hemorrhage can be associated with:

• Conjunctival vascular lesions
• Amyloid deposition
• Other local conjunctival pathology

SCH in Newborns

Subconjunctival hemorrhage may occur in newborns after:

• Vaginal delivery
• Instrument-assisted delivery

It usually resolves spontaneously and is generally benign when isolated.

Expected Outcome

The prognosis for uncomplicated SCH is:

Excellent.

It does not usually cause:

• Permanent visual loss
• Corneal damage
• Intraocular bleeding

The main issue is its alarming appearance.

Potential Complications

Complications are rare.

Possible problems include:

• Corneal dellen adjacent to a very elevated hemorrhage
• Identification of previously unrecognized systemic bleeding disorder
• Associated ocular injury when SCH results from significant trauma

The hemorrhage itself usually leaves:

No permanent ocular damage.

High-Yield Takeaways

• Subconjunctival hemorrhage is blood trapped beneath the conjunctiva and usually presents as a painless, sharply demarcated bright-red patch with normal vision.
• Common precipitants include coughing, sneezing, vomiting, straining, eye rubbing, and minor trauma.
• Important systemic associations include hypertension, anticoagulant or antiplatelet therapy, thrombocytopenia, and coagulation disorders.
• Most isolated spontaneous cases are benign and require reassurance only.
• Resolution typically occurs within 1–2 weeks, although large hemorrhages may persist longer.
• Mild spreading or color change during healing is usually normal.
• Routine laboratory testing is not indicated for a single uncomplicated episode.
• Recurrent or unexplained SCH should prompt consideration of blood pressure measurement, CBC/platelets, PT/INR, and aPTT according to the clinical setting.
• Do not automatically discontinue anticoagulants or antiplatelet medications because of an isolated SCH.
• Significant pain, photophobia, or reduced vision is not characteristic and should prompt evaluation for another diagnosis.
• Following trauma, an extensive, bullous, or 360-degree SCH may be a warning sign of occult globe rupture.
• A large elevated hemorrhage near the limbus can rarely cause corneal dellen, for which lubrication and follow-up are appropriate.
• The long-term prognosis is excellent, and uncomplicated SCH does not normally damage vision.

Ophthalmology – Sturge–Weber Syndrome

What the Syndrome Represents

Sturge–Weber syndrome (SWS) is a sporadic congenital neurocutaneous vascular disorder characterized by variable involvement of:

• Facial port-wine birthmark/capillary malformation
• Leptomeningeal vascular malformation
• Ocular vascular abnormalities

The classic ophthalmic manifestations are:

• Glaucoma
• Diffuse choroidal hemangioma
• Episcleral/conjunctival vascular dilation

Not every patient has all three systems involved.

The Modern Genetic Basis

SWS is usually caused by a postzygotic somatic activating mutation in:

GNAQ

most commonly involving:

p.Arg183Gln (R183Q)

Because the mutation occurs after fertilization:

• Only a subset of cells carries it
• Disease distribution is mosaic
• Severity varies substantially
• SWS is usually not inherited

This explains why familial transmission is exceedingly uncommon.

Relationship to Port-Wine Birthmarks

The facial lesion traditionally called a nevus flammeus is more accurately termed a:

Port-wine birthmark or capillary malformation

It is caused by ectatic dermal capillaries and is present from birth.

Color may range from:

• Pale pink
• Red
• Dark red
• Purple

Over time, untreated lesions may become:

• Darker
• Thicker
• Nodular

Distribution of the Facial Birthmark

Older descriptions classified lesions according to:

• V1
• V2
• V3 trigeminal dermatomes

Modern understanding is that facial capillary malformations follow:

Embryologic vascular territories rather than true trigeminal nerve dermatomes.

The distribution most strongly associated with intracranial SWS is:

Forehead and upper-eyelid involvement

particularly when the lesion crosses the midline forehead or involves a broad frontotemporal region.

Why Upper-Eyelid Involvement Matters

A port-wine birthmark involving the:

Upper eyelid

substantially raises concern for:

• Ipsilateral glaucoma
• Ocular vascular abnormalities
• Possible intracranial involvement

These children warrant early ophthalmic assessment.

How Common It Is

SWS is rare, with an estimated frequency of roughly:

1 in 20,000–50,000 live births

depending on the population studied.

There is no strong:

• Sex predilection
• Racial predilection

The Main Eye Problems

Ocular manifestations can include:

• Glaucoma
• Diffuse choroidal hemangioma
• Dilated conjunctival vessels
• Dilated episcleral vessels
• Retinal vascular tortuosity
• Serous retinal detachment
• Refractive error
• Anisometropia
• Amblyopia
• Buphthalmos in early-onset glaucoma

Glaucoma in SWS

Glaucoma is one of the most important causes of visual morbidity.

It is usually:

• Ipsilateral to the facial capillary malformation
• More likely when the eyelids are involved

Glaucoma may present:

• In infancy
• During childhood
• In adolescence
• In adulthood

Therefore risk is:

Lifelong.

Why Glaucoma Develops

Two major mechanisms are recognized.

Early-Onset Glaucoma

Usually related to:

Developmental angle abnormalities

similar to congenital glaucoma.

Later-Onset Glaucoma

More often related to:

Elevated episcleral venous pressure

caused by abnormal episcleral and orbital venous drainage.

Many patients have a combination of both mechanisms.

Early-Onset Glaucoma Features

Infants may develop:

• Buphthalmos
• Enlarged corneal diameter
• Corneal edema
• Haab striae
• Photophobia
• Tearing

Because the infant eye is elastic, elevated IOP can enlarge the globe.

Later-Onset Glaucoma Features

Older children and adults may show:

• Elevated IOP
• Open angles
• Dilated episcleral vessels
• Progressive optic nerve cupping
• Visual-field loss

The eye may not be enlarged.

Episcleral Vascular Abnormalities

Dilated episcleral vessels are common and may appear:

• Tortuous
• Engorged
• Reddish-purple

These vessels reflect abnormal venous drainage and can contribute directly to:

Elevated IOP.

Why Glaucoma Surgery Is More Difficult

Eyes with SWS are at increased risk during glaucoma surgery because of:

• Elevated episcleral venous pressure
• Choroidal vascular congestion
• Diffuse choroidal hemangioma

Complications may include:

• Choroidal effusion
• Serous retinal detachment
• Suprachoroidal hemorrhage
• Hypotony-related complications

Careful surgical planning is therefore essential.

Diffuse Choroidal Hemangioma

A characteristic ocular finding is a:

Diffuse choroidal hemangioma

usually involving the eye ipsilateral to the facial birthmark.

Unlike a circumscribed choroidal hemangioma, the lesion:

• Has poorly defined borders
• Involves a broad area of choroid
• Produces generalized choroidal thickening

The Classic “Tomato-Ketchup” Fundus

Because of diffuse choroidal vascular thickening, the affected fundus may appear:

Deep red-orange

compared with the fellow eye.

This is classically described as the:

“Tomato-ketchup fundus.”

How a Diffuse Choroidal Hemangioma Affects Vision

The lesion itself may initially be asymptomatic.

Visual loss develops when it causes:

• Subretinal fluid
• Serous retinal detachment
• Macular edema
• RPE alterations
• Refractive changes

Chronic fluid can produce permanent photoreceptor damage.

Other Posterior Segment Findings

Additional findings can include:

• Retinal vascular tortuosity
• Dilated retinal vessels
• RPE mottling
• Serous retinal detachment
• Chronic macular structural damage

Ultrasound Findings

B-scan ultrasonography may demonstrate:

• Diffuse choroidal thickening

A-scan typically shows:

High internal reflectivity

consistent with a vascular lesion.

Ultrasound can be particularly useful when:

• Fundus visualization is difficult
• Tumor thickness needs documentation

OCT in Choroidal Disease

Enhanced-depth imaging OCT may demonstrate:

• Increased choroidal thickness
• Expanded choroidal vascular spaces
• Subretinal fluid
• RPE abnormalities

Macular OCT is particularly useful for monitoring:

Exudation and treatment response.

Fluorescein and Indocyanine Green Angiography

Angiography may help define vascular abnormalities.

ICGA can show:

• Diffuse choroidal hypervascularity
• Abnormal choroidal filling
• Late washout patterns

It is mainly used when treatment planning or diagnostic uncertainty exists.

Neurologic Involvement

The characteristic CNS lesion is:

Leptomeningeal capillary-venous malformation

usually affecting the cerebral hemisphere ipsilateral to the facial lesion.

Commonly involved regions include:

• Occipital lobe
• Parietal lobe
• Posterior frontal regions

Why the Brain Becomes Injured

Abnormal leptomeningeal venous drainage can produce:

• Chronic venous congestion
• Reduced cerebral perfusion
• Ischemic injury
• Cortical atrophy
• Calcification

Over time this can lead to:

• Seizures
• Stroke-like episodes
• Hemiparesis
• Visual-field defects
• Developmental impairment

Seizures

Seizures are the most common neurologic manifestation.

They often begin in:

• Infancy
• Early childhood

Early-onset and poorly controlled seizures are associated with greater risk of:

• Developmental delay
• Neurologic disability

Stroke-Like Episodes

Patients may develop transient or persistent:

• Hemiparesis
• Hemiplegia
• Language disturbance
• Visual-field loss

These episodes are thought to relate to:

• Venous congestion
• Perfusion abnormalities
• Seizure-related metabolic stress

rather than conventional embolic stroke in many cases.

Visual-Field Loss From Brain Disease

Occipital cortical involvement can produce:

Contralateral homonymous hemianopia

or other retrochiasmal visual-field defects.

Thus visual impairment in SWS may originate from:

• Eye disease
• Brain disease
• Both

Headache and Migraine

Headache is common and may resemble:

• Migraine with aura
• Migraine without aura

Headache can coexist with:

• Seizures
• Transient neurologic deficits

Developmental and Cognitive Effects

Neurologic disease may be associated with:

• Developmental delay
• Learning difficulties
• Intellectual disability
• Behavioral problems

Severity correlates broadly with:

• Extent of brain involvement
• Seizure burden
• Age at seizure onset

Best Neuroimaging Test

The preferred study is:

Contrast-enhanced MRI of the brain

often supplemented with:

• Susceptibility-weighted imaging
• Perfusion imaging
• Other advanced sequences

MRI can demonstrate:

• Leptomeningeal enhancement
• Cortical atrophy
• Enlarged deep medullary veins
• Abnormal venous drainage
• Calcification-related signal changes

Role of CT

CT may demonstrate classic:

Gyriform cortical calcification

historically called:

“Tram-track” calcification

However, CT is no longer the preferred screening modality in children because of:

• Ionizing radiation
• Lower sensitivity for early leptomeningeal disease

Important Limitation of Early MRI

A normal MRI in a young infant does:

Not always completely exclude early SWS brain involvement.

If clinical suspicion remains high or neurologic symptoms develop, repeat imaging may be necessary.

Who Needs Neurologic Evaluation

Particular concern exists in children with:

• Forehead port-wine birthmark
• Upper-eyelid involvement
• Seizures
• Developmental abnormalities
• Focal neurologic deficits

Evaluation should be coordinated with:

Pediatric neurology.

An Important Modern Correction About Choroidal Hemangioma

Older teaching suggested that choroidal hemangioma almost always implies:

Leptomeningeal angiomatosis

This is too strong.

Diffuse choroidal hemangioma should raise suspicion for SWS, but intracranial involvement must be established by:

• Clinical evaluation
• Appropriate neuroimaging

rather than assumed.

How the Diagnosis Is Established

Diagnosis is clinical and based on some combination of:

• Facial capillary malformation
• Ocular abnormalities
• Leptomeningeal vascular malformation

Not every patient has the complete classic triad.

Patients With Only a Facial Port-Wine Birthmark

A facial port-wine birthmark alone does:

Not automatically mean Sturge–Weber syndrome.

Risk depends strongly on:

• Location
• Extent
• Associated ocular findings
• Neurologic findings

Important Differential Diagnoses

Consider:

• Klippel–Trénaunay syndrome
• Phakomatosis pigmentovascularis
• Isolated facial capillary malformation
• Other cerebral vascular malformations
• Diffuse choroidal hemangioma without classic SWS

Klippel–Trénaunay Syndrome

This condition typically features:

• Capillary malformation of an extremity
• Venous/lymphatic malformations
• Limb hypertrophy or overgrowth

It should not simply be considered “SWS plus an extremity port-wine stain”; it is a distinct vascular-overgrowth disorder.

Treating the Port-Wine Birthmark

The principal treatment is:

Pulsed-dye laser therapy

Treatment often begins in:

• Infancy
• Early childhood

Earlier treatment may improve:

• Lightening
• Cosmetic outcome
• Prevention of later thickening

Multiple sessions are usually required.

Treating Glaucoma Medically

Topical IOP-lowering therapy may include:

• Beta-blockers
• Carbonic anhydrase inhibitors
• Prostaglandin analogues
• Alpha-2 agonists when age-appropriate

There is no universal rigid first-, second-, and third-line order.

Treatment should be individualized according to:

• Age
• IOP
• Optic nerve status
• Systemic contraindications

Why Medical Therapy Often Becomes Insufficient

SWS glaucoma can be difficult to control because elevated episcleral venous pressure limits aqueous drainage.

Many patients eventually require:

Surgery.

Angle Surgery in Young Children

For early-onset glaucoma with developmental angle abnormality, options include:

• Goniotomy
• Trabeculotomy

These are most useful when angle dysgenesis is a major component.

Filtering Surgery

Older children and adults may require:

• Trabeculectomy
• Glaucoma drainage device

However, elevated episcleral venous pressure can reduce success and increase postoperative complications.

Glaucoma Drainage Devices

Tube shunts may be useful for:

• Refractory glaucoma
• Failed previous procedures
• High-risk filtering surgery

Examples include:

• Ahmed valve
• Baerveldt implant

Cyclodestructive Procedures

Cyclophotocoagulation may be considered in:

• Refractory glaucoma
• Limited visual potential
• Multiple prior surgical failures

It is generally not the first surgical choice in an eye with good visual potential.

Treating Diffuse Choroidal Hemangioma

Treatment is indicated when the hemangioma causes:

• Subretinal fluid
• Macular involvement
• Serous retinal detachment
• Significant visual loss

Observation is reasonable when the lesion is:

• Asymptomatic
• Nonexudative

Photodynamic Therapy

Verteporfin photodynamic therapy (PDT) is an important treatment for symptomatic choroidal hemangioma.

Advantages include:

• Selective vascular closure
• Resolution of subretinal fluid
• Relative preservation of surrounding retina

It is particularly useful when the exudative area is sufficiently localized for treatment.

Radiotherapy

Extensive diffuse choroidal hemangioma may require:

• Low-dose external beam radiotherapy
• Proton beam therapy
• Plaque radiotherapy in selected cases

Radiation is especially useful for:

• Broad diffuse lesions
• Extensive serous detachment
• Disease unsuitable for focal PDT

Why Conventional Laser Is Less Attractive

Thermal laser photocoagulation has historically been used, but it may produce:

• RPE damage
• Chorioretinal scarring

Modern management more commonly favors:

• PDT
• Radiotherapy

depending on lesion extent.

Correcting Refractive Error

SWS may produce:

• Myopia
• Hyperopia
• Astigmatism
• Anisometropia

Early optical correction is important, particularly in children.

Preventing Amblyopia

Amblyopia may result from:

• Anisometropia
• Glaucoma
• Corneal enlargement
• Retinal disease
• Strabismus

Treatment may include:

• Spectacle correction
• Contact lenses
• Patching
• Atropine penalization in selected cases

Early intervention is important for visual development.

Treating Seizures

Neurologic therapy commonly includes:

Antiseizure medication

with the objective of rapid and sustained seizure control.

Refractory epilepsy may require evaluation at a:

Pediatric epilepsy center.

Neurosurgical Options

For severe medically refractory epilepsy arising predominantly from one damaged hemisphere, surgery may include:

• Focal cortical resection
• Hemispherotomy
• Functional hemispherectomy

Modern epilepsy surgery generally favors disconnection procedures rather than older anatomical hemispherectomy techniques.

Role of Low-Dose Aspirin

Low-dose aspirin has been used in selected children with SWS in an attempt to reduce:

• Stroke-like episodes
• Seizure-associated ischemic events

However:

It is not a universal treatment for every SWS patient.

Use should be individualized by neurology after weighing:

• Potential benefit
• Bleeding risk
• Age
• Clinical phenotype

Multidisciplinary Follow-Up

Depending on disease involvement, care may include:

• Ophthalmology
• Neurology
• Dermatology
• Epileptology/neurosurgery
• Developmental pediatrics
• Physical and occupational therapy

Ophthalmic Surveillance

Children at ocular risk require regular assessment of:

• IOP
• Corneal diameter
• Axial length in selected cases
• Optic nerve
• Refraction
• Amblyopia
• Choroid
• Retina

Follow-up frequency depends on:

• Age
• Glaucoma status
• Ocular findings

Why Lifelong Eye Follow-Up Is Needed

Glaucoma may first appear:

Years after infancy

even when neonatal examinations were normal.

Therefore patients with high-risk facial or ocular involvement require:

Long-term surveillance.

Expected Visual Outcome

Visual prognosis depends primarily on:

• Glaucoma control
• Amblyopia prevention
• Macular involvement from choroidal hemangioma
• Serous retinal detachment
• Neurologic visual-field defects

Good vision can be maintained when ocular disease is identified and managed early.

Factors Affecting Neurologic Outcome

Poorer neurologic prognosis is associated with:

• Early seizure onset
• Frequent uncontrolled seizures
• Extensive bilateral or hemispheric brain involvement
• Recurrent stroke-like episodes

Some patients with limited disease have:

Normal intelligence and near-normal life expectancy.

Major Long-Term Complications

Important complications include:

• Glaucoma
• Buphthalmos
• Optic nerve damage
• Amblyopia
• Serous retinal detachment
• Macular photoreceptor damage
• Homonymous visual-field loss
• Seizures
• Hemiparesis
• Developmental impairment

High-Yield Takeaways

• Sturge–Weber syndrome is a sporadic neurocutaneous vascular disorder usually caused by a somatic mosaic GNAQ mutation.
• The classic manifestations involve facial capillary malformation, leptomeningeal vascular malformation, and ocular vascular disease, but not every patient has the full triad.
• The facial lesion is better termed a port-wine birthmark/capillary malformation, not simply a nevus distributed along trigeminal dermatomes.
• Forehead and upper-eyelid involvement carries particularly important risk for ocular and neurologic disease.
• The major ophthalmic threats are glaucoma and diffuse choroidal hemangioma.
• SWS glaucoma may be caused by developmental angle abnormalities in early childhood and elevated episcleral venous pressure later in life.
• Glaucoma risk is lifelong, so a normal infant examination does not eliminate the need for later surveillance.
• Early-onset glaucoma can produce buphthalmos, corneal enlargement, and Haab striae.
• The classic diffuse choroidal hemangioma produces the “tomato-ketchup fundus.”
• Choroidal hemangioma becomes clinically important when it causes subretinal fluid, macular edema, or serous retinal detachment.
• PDT is useful for selected symptomatic choroidal hemangiomas; extensive diffuse disease may require low-dose radiotherapy or proton therapy.
• Contrast-enhanced MRI is preferred for evaluating leptomeningeal involvement; CT mainly demonstrates later cortical calcification.
• Early MRI can occasionally be falsely reassuring, so repeat imaging may be needed when neurologic suspicion remains high.
• Choroidal hemangioma does not automatically prove leptomeningeal involvement.
• Seizures are the most frequent neurologic manifestation and require early aggressive management.
• Low-dose aspirin is used in selected neurologic cases but is not routine therapy for every patient.
• Glaucoma surgery may be technically difficult because of elevated episcleral venous pressure and the risk of choroidal effusion or hemorrhage.
• Early refraction and amblyopia therapy are essential in children.
• Long-term care requires coordinated ophthalmic, neurologic, dermatologic, and developmental follow-up.

Ophthalmology – Stickler Syndrome

What the Syndrome Represents

Stickler syndrome is an inherited collagen disorder characterized by a variable combination of:

• Abnormal vitreous architecture
• High myopia
• Peripheral retinal degeneration
• Markedly increased risk of rhegmatogenous retinal detachment
• Hearing impairment
• Craniofacial abnormalities
• Early-onset arthropathy

From an ophthalmic standpoint, the most important complication is:

Retinal detachment, often occurring at a young age and sometimes bilaterally.

Why the Retina and Vitreous Are Affected

Stickler syndrome results from pathogenic variants affecting structural collagens important in:

• Vitreous
• Cartilage
• Inner ear
• Craniofacial development

Relevant collagens include:

• Type II
• Type IX
• Type XI

Abnormal collagen alters vitreous development and increases:

Vitreoretinal traction and peripheral retinal susceptibility to breaks.

How Common It Is

Stickler syndrome is among the more common inherited connective-tissue disorders.

Estimated prevalence is approximately:

1 in 7,500–10,000

although milder cases may go unrecognized.

Main Genetic Forms

The most important forms are:

Type 1 Stickler Syndrome

Caused by:

COL2A1

Inheritance:

Autosomal dominant

This is the most common form and usually has prominent ocular involvement.

Type 2 Stickler Syndrome

Caused by:

COL11A1

Inheritance:

Autosomal dominant

Often associated with:

• Ocular disease
• Hearing loss
• Craniofacial features

A characteristic vitreous phenotype may be present.

Type 3 Stickler Syndrome

Caused by:

COL11A2

Inheritance is usually:

Autosomal dominant

Because COL11A2 is not expressed in the vitreous, this form is classically:

Nonocular Stickler syndrome

with mainly:

• Hearing
• Skeletal
• Craniofacial manifestations

Recessive Stickler Syndrome

Autosomal recessive forms may result from pathogenic variants in:

• COL9A1
• COL9A2
• COL9A3

These can also produce significant ocular disease.

Other rare Stickler-like collagen disorders continue to be genetically characterized.

Important COL2A1 Nuance

An older teaching stated that COL2A1 mutations must involve exon 2 for ocular disease.

That is:

Incorrect as a general rule.

Many COL2A1 variants outside exon 2 produce classic ocular Stickler syndrome.

However, variants involving the alternatively spliced:

Exon 2

can produce a predominantly or nearly exclusively ocular phenotype because that exon is particularly relevant to vitreous collagen expression.

How It Is Inherited

Most classic Stickler syndrome is:

Autosomal dominant

Therefore an affected individual typically has a:

50% chance of transmitting the pathogenic variant to each child.

However, expression is variable, so family members with the same mutation may differ substantially in:

• Myopia
• Hearing loss
• Joint disease
• Retinal complications

Why Family History May Be Misleading

A negative family history does not exclude Stickler syndrome because:

• Disease expression can be mild
• Relatives may have been undiagnosed
• De novo pathogenic variants can occur
• Ocular and systemic features vary considerably

The Classic Vitreous Phenotypes

Vitreous examination can provide an important diagnostic clue.

COL2A1 / Type 1

Classically associated with:

Membranous vitreous phenotype

with:

• Retrolental membrane-like condensation
• Optically empty vitreous cavity

COL11A1 / Type 2

Classically associated with:

Beaded vitreous phenotype

with:

• Irregular fibrillar condensations
• Bead-like strands

These patterns are helpful but are not absolutely present in every patient.

Optically Empty Vitreous

A striking finding can be:

Abnormally clear or optically empty central vitreous

with abnormal peripheral condensations or veils.

This may initially look deceptively normal unless the examiner specifically searches for the characteristic vitreous architecture.

Myopia

High myopia is very common and may be present:

• Congenitally
• In early childhood

Unlike ordinary school-age myopia, Stickler-associated myopia may be:

High from a very young age

and may not necessarily show the same progressive axial pattern as conventional myopia.

Why Early Refraction Matters

Uncorrected high ametropia can cause:

• Reduced visual development
• Refractive amblyopia
• Strabismus

Therefore children require:

Early cycloplegic refraction and prompt optical correction.

Peripheral Retinal Abnormalities

Peripheral findings may include:

• Lattice degeneration
• Radial or circumferential vitreoretinal degeneration
• Retinal holes
• Horseshoe tears
• Giant retinal tears

The peripheral retina must therefore be examined carefully.

Why Retinal Detachment Risk Is So High

The combination of:

• Abnormal vitreous
• Strong vitreoretinal adhesions
• Peripheral retinal degeneration
• High myopia

creates a strong predisposition to:

Rhegmatogenous retinal detachment.

Detachment can occur:

• In childhood
• In adolescence
• In young adulthood

and may be bilateral.

How High Is the Retinal Detachment Risk?

Lifetime risk is substantial, particularly in:

COL2A1-associated type 1 Stickler syndrome.

Published estimates vary according to genotype and cohort, but untreated high-risk families may have retinal detachment rates:

Well above those of the general population and sometimes exceeding 50%.

Risk should therefore be considered clinically significant even in an asymptomatic child.

Character of Retinal Detachment in Stickler Syndrome

Detachments may be unusually complex because they can involve:

• Multiple retinal breaks
• Giant retinal tears
• Extensive vitreoretinal traction
• Bilateral disease
• Proliferative vitreoretinopathy

This makes repair potentially more difficult than routine RRD.

Why the Fellow Eye Matters

A patient presenting with Stickler-associated RD in one eye remains at substantial risk in the:

Fellow eye

and requires careful peripheral retinal examination and discussion of:

• Surveillance
• Prophylactic options

Cataract Pattern

Stickler syndrome may be associated with cataract, classically:

Peripheral cortical wedge-shaped cataract

Other cataract morphologies can also occur.

Cataract may develop:

• Spontaneously
• Earlier than expected for age

Glaucoma

Glaucoma occurs in a subset of patients.

Potential mechanisms include:

• Developmental angle abnormalities
• Secondary changes
• Postoperative factors

Long-term examination should therefore include:

• IOP
• Optic nerve assessment

Hearing Abnormalities

Hearing loss is common, especially in certain genotypes.

It may be:

• Sensorineural
• Conductive
• Mixed

Severity ranges widely.

Formal:

Audiologic assessment

is recommended when Stickler syndrome is suspected or confirmed.

Craniofacial Findings

Characteristic facial features can include:

• Midface hypoplasia
• Flat nasal bridge
• Anteverted nares
• Micrognathia

Findings may become less obvious with age.

Pierre Robin Sequence

Stickler syndrome is an important genetic cause of:

Pierre Robin sequence

which consists of:

• Micrognathia
• Glossoptosis
• Upper-airway obstruction

often accompanied by:

• Cleft palate

Palatal Abnormalities

Patients may have:

• Cleft palate
• Submucous cleft
• Bifid uvula

A subtle palatal abnormality may provide an important clue in a patient presenting primarily with retinal disease.

Skeletal Manifestations

Musculoskeletal features may include:

• Joint hypermobility in childhood
• Joint pain
• Early degenerative osteoarthritis
• Spondyloepiphyseal abnormalities
• Mild scoliosis

Some patients develop significant arthritis relatively early in adulthood.

Height and Body Habitus

Body habitus is variable.

Patients may have:

• Slender build
• Long extremities

but classic Marfan-type disproportion is not required.

Mitral Valve Prolapse – Modern Perspective

Older descriptions frequently emphasized:

Mitral valve prolapse

as a common Stickler association.

Modern evidence does not support routine cardiologic screening solely for Stickler syndrome in otherwise asymptomatic patients.

Cardiac evaluation should instead be driven by:

• Clinical findings
• Murmur
• Symptoms
• Additional connective-tissue features

How the Diagnosis Is Suspected

History should specifically ask about:

• High myopia from childhood
• Retinal tear or detachment
• Family history of RD
• Cleft palate
• Pierre Robin sequence
• Hearing loss
• Early arthritis

The combination of:

Early high myopia + abnormal vitreous + retinal detachment history

is particularly suggestive.

What the Eye Examination Should Include

A complete evaluation includes:

• Visual acuity
• Cycloplegic refraction in children
• Slit-lamp examination
• Vitreous assessment
• Dilated peripheral retinal examination
• Scleral depression when appropriate
• IOP
• Optic nerve examination

Why Vitreous Examination Is Crucial

Recognizing the characteristic:

• Membranous
• Beaded
• Optically empty

vitreous phenotype can allow diagnosis before:

A retinal detachment occurs.

This may provide the opportunity for:

• Genetic confirmation
• Family screening
• Preventive retinal management