Medicine – Uveitis

Uveitis is inflammation involving the uveal tract of the eye, which consists of the iris, ciliary body, and choroid. Inflammation may be limited to one anatomical region or involve several parts of the eye.

Uveitis is clinically important because recurrent or severe inflammation can cause permanent visual impairment through complications such as cataract, glaucoma, macular oedema, retinal damage, or optic nerve involvement.

1. Classification of Uveitis

Uveitis is classified according to the main anatomical site of inflammation.

Anterior uveitis mainly affects the iris and anterior ciliary body and is the most common form.

Intermediate uveitis predominantly affects the vitreous and peripheral retina.

Posterior uveitis primarily involves the choroid and/or retina.

Panuveitis involves the anterior chamber, vitreous, and retina or choroid.

The underlying causes differ somewhat according to the anatomical pattern.

2. Anterior Uveitis

Anterior uveitis is often called iritis when inflammation primarily affects the iris or iridocyclitis when both the iris and ciliary body are involved.

The typical presentation is:

Painful red eye + photophobia + blurred vision.

The redness is often most prominent around the cornea, producing ciliary or circumcorneal injection.

3. Clinical Features

Patients with acute anterior uveitis commonly experience ocular pain, redness, photophobia, excessive tearing, and reduced or blurred vision.

Photophobia can be particularly prominent because movement of the inflamed iris and ciliary body causes discomfort.

Unlike acute angle-closure glaucoma, the pupil in anterior uveitis is often small or irregular, rather than fixed and mid-dilated.

4. Cells and Flare

Slit-lamp examination may demonstrate cells and flare in the anterior chamber.

Cells represent inflammatory cells circulating within the aqueous humour.

Flare results from increased protein entering the aqueous because inflammation disrupts the blood-aqueous barrier.

Therefore:

Anterior chamber cells + flare → characteristic evidence of anterior uveitis.

5. Posterior Synechiae

Inflammation can cause the posterior surface of the iris to adhere to the anterior lens capsule.

These adhesions are called posterior synechiae.

They can produce an irregular pupil and, when extensive, interfere with normal aqueous humour circulation.

This is one reason why cycloplegic/mydriatic drops are often used in anterior uveitis.

Causes of Uveitis

Uveitis has a very broad differential diagnosis. Causes include idiopathic disease, immune-mediated systemic disorders, infection, trauma, and ocular-specific inflammatory conditions.

6. Idiopathic Uveitis

A substantial proportion of patients have no identifiable systemic or infectious cause, even after appropriate investigation.

These cases are classified as idiopathic uveitis.

The extent of investigation depends on the patient’s age, anatomical type of uveitis, whether disease is unilateral or bilateral, recurrence, severity, and associated systemic features.

7. Ankylosing Spondylitis

Ankylosing spondylitis is one of the classic systemic associations with acute anterior uveitis.

The uveitis is often:

Acute + unilateral + painful + recurrent.

It is strongly associated with HLA-B27.

Some patients presenting with recurrent anterior uveitis may have previously unrecognised axial spondyloarthritis.

8. Reactive Arthritis

Reactive arthritis, formerly called Reiter syndrome, is another HLA-B27-associated spondyloarthritis that may cause ocular inflammation.

Patients may develop conjunctivitis or acute anterior uveitis.

Other features can include arthritis and urethritis or cervicitis following an appropriate gastrointestinal or genitourinary infection.

The modern term reactive arthritis is preferred over Reiter syndrome.

9. Psoriatic Disease

Psoriatic arthritis and other forms of psoriatic spondyloarthritis can be associated with uveitis.

Anterior uveitis is particularly relevant in patients with psoriatic disease who also have features of axial or HLA-B27-associated spondyloarthritis.

10. Inflammatory Bowel Disease

Both Crohn disease and ulcerative colitis can have extraintestinal ocular manifestations.

These include:

Episcleritis.

Anterior uveitis.

Uveitis does not necessarily parallel intestinal disease activity and may occasionally occur independently of a gastrointestinal flare.

11. The Spondyloarthritis Connection

An important examination pattern is the relationship between HLA-B27 spondyloarthritis and acute anterior uveitis.

Remember:

Ankylosing spondylitis → anterior uveitis.

Reactive arthritis → anterior uveitis/conjunctivitis.

Psoriatic arthritis → anterior uveitis.

IBD-associated arthritis → anterior uveitis.

These disorders belong to the broader seronegative spondyloarthritis family.

12. Sarcoidosis

Sarcoidosis is an important systemic cause of uveitis.

It can produce anterior, intermediate, posterior, or panuveitis, and ocular disease may be unilateral or bilateral.

Other clues to sarcoidosis may include pulmonary disease, bilateral hilar lymphadenopathy, erythema nodosum, lupus pernio, or other systemic manifestations.

Therefore:

Sarcoidosis + eye inflammation → think uveitis.

13. Juvenile Idiopathic Arthritis

The older term juvenile chronic arthritis has largely been replaced by juvenile idiopathic arthritis (JIA).

JIA is an important cause of chronic anterior uveitis in children.

Unlike the painful red eye of typical HLA-B27-associated acute uveitis, JIA-associated uveitis may be silent and asymptomatic, particularly early in the disease.

For this reason, children in relevant JIA risk groups require regular slit-lamp screening, even when they have no ocular symptoms.

14. Trauma

Ocular trauma can produce anterior uveal inflammation known as traumatic iritis.

It may develop following blunt trauma to the eye and cause:

Pain + photophobia + redness + blurred vision.

A history of recent ocular injury is therefore an important clue.

Infectious Causes

Infectious uveitis is particularly important to recognise because inappropriate immunosuppression without treating the infection can allow the underlying infection to worsen.

15. Tuberculosis

Tuberculosis can produce several patterns of intraocular inflammation, including posterior uveitis and choroidal disease.

Ocular TB may occur with or without obvious active pulmonary tuberculosis.

Diagnosis can be difficult and generally requires interpretation of ocular findings alongside systemic investigation and evidence of TB infection.

16. Herpes Simplex Virus

Herpes simplex virus (HSV) can cause anterior uveitis, sometimes in association with keratitis.

Herpetic anterior uveitis may be unilateral and can be associated with raised intraocular pressure.

Varicella-zoster virus is another important herpesvirus capable of producing similar ocular inflammation.

17. Toxoplasmosis

Toxoplasma gondii is a particularly important cause of posterior uveitis, specifically retinochoroiditis.

Patients may present with floaters and reduced or blurred vision.

Fundoscopy classically demonstrates an area of active retinal inflammation, sometimes adjacent to an old pigmented scar.

Therefore:

Toxoplasmosis → think posterior uveitis / retinochoroiditis.

18. Toxocariasis

Toxocara infection can cause ocular disease, particularly in children and young people.

Ocular toxocariasis can produce posterior segment inflammation and retinal granulomas, sometimes causing significant unilateral visual impairment.

It is an important infectious differential diagnosis of posterior ocular inflammation.

19. Other Important Infectious Causes

The original list is not exhaustive.

Depending on the patient’s immune status and clinical presentation, other important infectious causes include varicella-zoster virus, cytomegalovirus, syphilis, and other bacterial, viral, fungal, or parasitic infections.

CMV retinitis is particularly important in patients with severe immunosuppression.

Treatment

20. Treatment Depends on the Cause

Management depends heavily on whether the uveitis is infectious or non-infectious and on which part of the eye is involved.

For non-infectious anterior uveitis, treatment commonly includes topical corticosteroids to suppress inflammation.

21. Cycloplegic and Mydriatic Drops

Cycloplegic/mydriatic agents are often given in anterior uveitis.

They help:

Relieve pain from ciliary muscle spasm.

Prevent or break posterior synechiae.

This is an important difference from some other causes of a painful red eye.

22. Systemic Treatment

Severe, posterior, bilateral, recurrent, or systemic inflammatory uveitis may require systemic corticosteroids or steroid-sparing immunosuppressive/biologic treatment under specialist supervision.

When an underlying systemic inflammatory disease is present, treating that disease is an important part of controlling the ocular inflammation.

23. Infectious Uveitis

When uveitis is caused by infection, the underlying pathogen requires specific antimicrobial therapy.

For example, management may require anti-tuberculous therapy, antiviral therapy, or anti-Toxoplasma treatment depending on the diagnosis.

This distinction is crucial because corticosteroid treatment without appropriate antimicrobial coverage can be dangerous in some infectious forms.

24. Complications

Uveitis can cause several important complications:

Posterior synechiae.

Cataract.

Secondary glaucoma.

Cystoid macular oedema.

Retinal damage.

Optic nerve damage.

Permanent visual impairment.

Early diagnosis and adequate control of inflammation therefore matter greatly.

25. Uveitis – Causes in Note Form

Idiopathic: no underlying cause identified.

Ankylosing spondylitis: classic association with recurrent acute anterior uveitis; often HLA-B27 related.

Reactive arthritis: formerly Reiter syndrome; may cause anterior uveitis or conjunctivitis.

Psoriatic arthritis: can be associated with anterior uveitis, especially with spondyloarthritis features.

Inflammatory bowel disease: Crohn disease and ulcerative colitis can cause anterior uveitis.

Sarcoidosis: important systemic cause; can affect anterior and posterior portions of the eye.

Juvenile idiopathic arthritis: chronic anterior uveitis that may be completely asymptomatic in children.

Trauma: blunt ocular injury may produce traumatic anterior uveitis/iritis.

Tuberculosis: may cause various forms of uveitis, including posterior involvement.

HSV: may cause unilateral anterior uveitis, sometimes with keratitis and raised IOP.

Toxoplasmosis: classic infectious cause of posterior uveitis/retinochoroiditis.

Toxocariasis: may cause posterior ocular inflammation and retinal granuloma.

Key Clinical Pattern

For examination purposes, remember:

Painful red eye + photophobia + small/irregular pupil + cells and flare → anterior uveitis.

The major systemic association is:

HLA-B27 spondyloarthritis → acute anterior uveitis.

This includes:

Ankylosing spondylitis + reactive arthritis + psoriatic arthritis + IBD-associated spondyloarthritis.

Also remember:

JIA → chronic anterior uveitis that may be asymptomatic.

Sarcoidosis → uveitis.

Toxoplasmosis → posterior uveitis/retinochoroiditis.

And a useful painful-red-eye distinction:

Uveitis → photophobia + small/irregular pupil.

Acute angle-closure glaucoma → hazy cornea + mid-dilated fixed pupil + markedly raised IOP.

Scleritis → severe deep boring pain + deep violaceous scleral redness.