Emergency and Acute Medicine – Transfusion Complications




Transfusion complications are relatively common clinical events associated with blood product administration, ranging from mild allergic reactions to life-threatening conditions. Approximately 5–6% of hospitalized patients receive transfusions, and about 2% of transfused units result in some type of reaction within 24 hours. Although mortality is rare, complications can be severe, especially with acute hemolytic reactions or pulmonary syndromes.


Noninfectious complications are more common than infectious ones. Febrile nonhemolytic reactions occur in approximately 1 in 500 red blood cell transfusions and are characterized by fever and chills due to antigen–antibody reactions involving leukocytes or cytokines. Allergic reactions are relatively frequent and usually mild, presenting with urticaria or pruritus, while anaphylaxis is rare but potentially fatal. Acute hemolytic transfusion reactions, often due to ABO incompatibility, are uncommon but dangerous, occurring in roughly 1 in 38,000 to 70,000 transfusions. Delayed hemolytic reactions occur days later and are typically less severe.


Transfusion-associated circulatory overload (TACO) is relatively common, particularly in elderly or volume-sensitive patients, and presents with signs of fluid overload such as dyspnea and hypertension. Transfusion-related acute lung injury (TRALI) is a serious complication presenting within 6 hours of transfusion with acute respiratory distress, bilateral pulmonary infiltrates, and normal cardiac function. It is a leading cause of transfusion-related mortality and must be distinguished from TACO and Acute Respiratory Distress Syndrome.


Other important complications include electrolyte disturbances such as hypocalcemia (due to citrate binding calcium) and hyperkalemia (from stored blood breakdown), iron overload with repeated transfusions, and rare but fatal graft-versus-host disease. Infectious complications are now rare due to screening but include transmission of viruses such as HIV, Hepatitis B, and Hepatitis C, as well as bacterial contamination (especially in platelet transfusions), which remains the most common infectious cause of mortality.


Acute intravascular hemolytic transfusion reactions are the most severe form and typically occur immediately due to ABO incompatibility, often from clerical or identification errors. Even small volumes (5–20 mL) can trigger symptoms. These reactions result in rapid destruction of transfused red blood cells, triggering a cascade involving cytokine release, activation of the coagulation system, and potential progression to shock, disseminated intravascular coagulation, renal failure, and respiratory failure.


Clinical manifestations of transfusion reactions vary widely but commonly include fever, chills, urticaria, dyspnea, hypotension, chest pain, nausea, and hemoglobinuria. Severe reactions may present with shock, bleeding, renal failure, or respiratory distress. The classic triad of fever, flank pain, and dark urine in hemolytic reactions is uncommon but highly suggestive when present.


Evaluation begins with immediate recognition of symptoms and verification of patient and blood product identity. Laboratory testing includes CBC, electrolytes, renal function, coagulation studies, bilirubin, and a direct Coombs test. Hemolysis may be indicated by hemoglobinemia or hemoglobinuria. Imaging such as chest x-ray is useful when pulmonary complications like TRALI are suspected, typically showing bilateral infiltrates without cardiomegaly.


Management requires immediate cessation of the transfusion as the first and most critical step. Supportive care follows the ABC approach, including oxygen supplementation and hemodynamic stabilization. Intravenous fluids with normal saline are used for hypotension, while avoiding lactated solutions or dextrose-containing fluids. Maintaining adequate urine output is essential to prevent renal failure, often requiring diuretics such as furosemide or osmotic agents like mannitol.


Febrile reactions are treated with antipyretics, while allergic reactions are managed with antihistamines such as diphenhydramine. Severe allergic or anaphylactic reactions require prompt administration of epinephrine and corticosteroids. In cases of electrolyte disturbances, calcium replacement may be necessary. If disseminated intravascular coagulation develops, it must be treated accordingly.


Patients with severe reactions, including hemolysis, anaphylaxis, pulmonary complications, or sepsis, require ICU admission and close monitoring. Mild febrile or allergic reactions may be managed conservatively and discharged with appropriate follow-up.


Key clinical pearls include the importance of strict patient identification and cross-matching procedures to prevent catastrophic hemolytic reactions. Clinicians should always suspect hemolysis when hypotension, dark urine, or unexplained bleeding occurs during transfusion. Additionally, transfusions should be used judiciously, as they carry significant risks despite their lifesaving potential.

​

Emergency and Acute Medicine – Toxoplasmosis

Emergency and Acute Medicine – Toxoplasmosis


Toxoplasmosis is an infection caused by Toxoplasma gondii, an intracellular protozoan that exists in three forms: tachyzoites (actively replicating), tissue cysts (chronic latent form), and oocysts (shed in cat feces). Transmission occurs primarily through ingestion of undercooked meat containing tissue cysts, ingestion of food or water contaminated with oocysts, or contact with cat feces or contaminated soil. Less common routes include transplacental transmission, blood transfusion, and organ transplantation.


Toxoplasmosis is extremely common worldwide, with approximately 70% of adults demonstrating prior exposure. Most immunocompetent individuals remain asymptomatic. Cats serve as the definitive host, and the incubation period typically ranges from 4 to 21 days.


Clinical manifestations vary depending on the host’s immune status and the type of infection. In immunocompromised patients, particularly those with HIV/AIDS, toxoplasmosis most commonly presents as encephalitis. Symptoms are typically subacute and include headache, fever, altered mental status, seizures, cranial nerve deficits, and focal neurologic signs. Neuropsychiatric symptoms such as psychosis, paranoia, or dementia may also occur. Pulmonary involvement may present as pneumonitis with dyspnea and nonproductive cough.


In immunocompetent individuals, approximately 90% of infections are asymptomatic. When symptoms occur, they usually present as a self-limited mononucleosis-like illness with cervical lymphadenopathy, fever, malaise, sore throat, and occasionally hepatosplenomegaly or rash. Rarely, severe complications such as encephalitis or pneumonitis may occur.


Ocular toxoplasmosis is an important manifestation, often presenting with blurred vision, scotoma, pain, and photophobia. Examination may reveal chorioretinitis with characteristic yellow-white retinal lesions. This form is particularly common in individuals with untreated congenital infection and may lead to long-term visual impairment.


Congenital toxoplasmosis results from maternal infection during pregnancy. Infection during the first trimester is associated with severe outcomes such as miscarriage or stillbirth, while later infections are more likely to be transmitted to the fetus but may present with delayed manifestations. Many affected infants are asymptomatic at birth but later develop neurologic or ocular complications, including blindness, seizures, or developmental delay.


Diagnosis involves a combination of clinical suspicion and laboratory testing. Detection of the organism may be achieved through analysis of blood, cerebrospinal fluid, bronchoalveolar lavage, or amniotic fluid. Serologic testing for IgM and IgG antibodies is commonly used, although interpretation can be challenging due to false positives and negatives. Imaging plays a key role in CNS disease: CT or MRI typically shows multiple bilateral ring-enhancing lesions. Chest radiography may reveal a reticulonodular pattern in pulmonary involvement.


The differential diagnosis includes Cryptococcal meningitis, Primary CNS lymphoma, Pneumocystis pneumonia, Cytomegalovirus retinitis, and mycobacterial infections, particularly in immunocompromised patients.


Management depends on disease severity and host immune status. Immunocompetent patients with mild disease typically require no treatment. Symptomatic or severe cases are treated with a combination of pyrimethamine, sulfadiazine, and folinic acid, or alternatively clindamycin in patients with sulfa allergy.


Immunocompromised patients require prompt and aggressive therapy, often initiated empirically when characteristic brain lesions are present. Treatment typically continues for 4–6 weeks after symptom resolution, and long-term prophylaxis may be necessary, particularly in patients with HIV.


Ocular disease is treated similarly, often with the addition of corticosteroids in cases involving the macula or optic nerve. In pregnancy, management is complex and requires specialist consultation; spiramycin is typically used early in pregnancy to reduce fetal transmission risk.


Patients with severe systemic disease, CNS involvement, or immunocompromise require hospital admission. Immunocompetent patients with mild disease can usually be managed as outpatients with follow-up.


Key clinical pearls include recognizing that toxoplasmosis is often asymptomatic in healthy individuals but can cause life-threatening disease in immunocompromised patients. CNS toxoplasmosis should always be suspected in patients with HIV presenting with focal neurologic deficits and ring-enhancing brain lesions. Prevention, particularly in pregnant women, includes avoiding undercooked meat and exposure to cat litter or contaminated soil.

Emergency and Acute Medicine – Toxic Shock Syndrome (TSS)




Toxic shock syndrome (TSS) is a severe, acute, life-threatening illness caused by toxin-producing bacteria, most commonly Staphylococcus aureus and less commonly Group A Streptococcus (referred to as streptococcal toxic shock syndrome, STSS). These organisms produce exotoxins such as toxic shock syndrome toxin (TSST-1) and streptococcal pyrogenic exotoxins, which act as superantigens. These toxins trigger massive cytokine release, leading to fever, immune dysregulation, and profound vasodilation with capillary leak, ultimately resulting in hypotension and shock.


The etiology of TSS has evolved over time. Initially associated with menstruating women using highly absorbent tampons, modern cases are now frequently nonmenstrual. These include infections related to surgical wounds, postpartum infections, burns, nasal packing, mastitis, osteomyelitis, and soft tissue infections. Many individuals are asymptomatic carriers of S. aureus in areas such as the nasal passages, skin, or genital tract. In streptococcal TSS, infection often follows minor trauma and may present with severe pain even before visible signs of infection appear.


Clinically, TSS is diagnosed using criteria established by the CDC. Patients typically present with high fever (>38.9°C), hypotension, and a diffuse blanching macular erythroderma rash. This rash is followed 1–2 weeks later by desquamation, especially of the palms and soles. Multisystem involvement is a hallmark and includes gastrointestinal symptoms (vomiting, diarrhea), musculoskeletal involvement (severe myalgias or elevated creatine phosphokinase), mucosal hyperemia (conjunctival, oral, or vaginal), renal dysfunction, hepatic involvement, hematologic abnormalities such as thrombocytopenia, and central nervous system symptoms including confusion or hallucinations.


Streptococcal TSS differs slightly in presentation and diagnostic criteria. It requires isolation of Group A Streptococcus from a sterile site, hypotension, and evidence of organ dysfunction such as renal failure, coagulopathy, liver dysfunction, acute respiratory distress syndrome, or soft tissue necrosis. A key distinguishing feature is severe pain, often out of proportion to physical findings, which may indicate deep soft tissue infection such as necrotizing fasciitis.


Laboratory findings are nonspecific but reflect systemic inflammation and organ dysfunction. These may include leukocytosis or leukopenia, elevated creatinine and liver enzymes, thrombocytopenia, electrolyte abnormalities (such as hypocalcemia), and elevated creatine phosphokinase. Cultures from blood or suspected infection sites should be obtained, although blood cultures are not always positive in staphylococcal TSS. Imaging such as chest radiography or CT may help identify the source of infection or complications.


The differential diagnosis includes Kawasaki disease, Scarlet fever, Stevens-Johnson syndrome, Rocky Mountain spotted fever, and meningococcemia. Differentiation is essential because management strategies differ significantly.


Management of TSS is a medical emergency and focuses on rapid stabilization and source control. Prehospital care includes airway management, IV access, and fluid resuscitation. In the emergency department, aggressive management of shock is critical, often requiring large volumes of intravenous fluids (up to 4–20 L in the first 24 hours). If hypotension persists, vasopressors such as norepinephrine or dopamine are initiated.


Identifying and removing the source of infection is essential, such as removing tampons, nasal packing, or infected wound material. Early surgical consultation is necessary if drainage or debridement is required, particularly in cases of suspected necrotizing infection.


Antibiotic therapy should be initiated promptly. Regimens typically include clindamycin or linezolid to suppress toxin production, combined with agents such as vancomycin for broad coverage. For confirmed methicillin-sensitive S. aureus, oxacillin or nafcillin may be used. In streptococcal TSS, broader-spectrum regimens including beta-lactams and clindamycin are recommended. Intravenous immunoglobulin (IVIG) may be considered, particularly in streptococcal TSS or refractory shock.


All patients with TSS require hospital admission, and most require intensive care due to the risk of rapid progression to multiorgan failure.


Key clinical pearls include recognizing the combination of fever, rash, hypotension, and multisystem involvement, and initiating aggressive supportive care immediately. Early antibiotic therapy, toxin suppression, and prompt source control are critical for survival.

​

Emergency and Acute Medicine – Torticollis




Torticollis, meaning “twisted neck,” is a clinical symptom rather than a disease entity. It refers to a fixed or dynamic abnormal posture of the head and neck, often involving rotation or tilting. It is also known as cervical dystonia or wry neck and may arise from a wide range of local or central causes.


The etiology of torticollis is broad and can be categorized into local and central causes. The most common form is acute wry neck, which typically develops अचानक (often overnight) without clear provocation and resolves spontaneously within 1–2 weeks. Local structural causes include cervical spine pathology such as fractures, dislocations, subluxations, spondylosis, tumors, ligamentous laxity (especially in the atlantoaxial region), and scar tissue from prior injury. Inflammatory or infectious causes include myositis, lymphadenitis, tuberculosis, and infections of surrounding tissues such as retropharyngeal abscess, meningitis, tonsillitis, mastoiditis, or sinusitis. Neurologic and neuromuscular causes include myasthenia gravis and neuritis. Compensatory torticollis may occur with ocular muscle palsy or head tremor.


Central causes include idiopathic spasmodic torticollis, which is more common in women aged 31–60 years, as well as dystonic disorders such as torsion dystonia, tardive dystonia from neuroleptic medications, Wilson disease, and toxic causes such as Strychnine poisoning. Drug-induced dystonia, particularly from antipsychotics, is a common acute cause and typically occurs within 12–23 hours of medication exposure.


In pediatric patients, causes include congenital abnormalities such as muscular torticollis due to sternocleidomastoid hypertrophy, vertebral anomalies, or syndromic conditions. Other causes include infections (e.g., otitis media, retropharyngeal abscess), trauma, gastroesophageal reflux, and central nervous system pathology such as posterior fossa tumors.


Clinically, patients present with intermittent or sustained painful spasms of the neck muscles, particularly the sternocleidomastoid and trapezius. The head is typically rotated and tilted to one side, with movements ranging from smooth deviation to jerking motions. Pure flexion (anterocollis) or extension (retrocollis) is uncommon. Symptoms are often exacerbated by activity, stress, or upright posture and typically resolve during sleep.


History should focus on recent trauma, medication exposure (especially antipsychotics), and systemic symptoms such as fever. On examination, the abnormal head posture is evident, and neurologic evaluation is essential. The presence of fever suggests an infectious cause, while focal neurologic deficits raise concern for central nervous system or spinal cord pathology. In congenital cases, a firm, nontender mass in the sternocleidomastoid muscle may be present.


Evaluation is directed at excluding serious causes. Cervical spine imaging is indicated when trauma is suspected. CT or MRI may be required if there is concern for abscess, tumor, or neurologic pathology. Ultrasound is the preferred modality for congenital muscular torticollis. No specific laboratory tests are routinely helpful.


Management depends on the underlying cause. Prehospital care includes ensuring airway patency, supporting the head, and maintaining cervical spine precautions if trauma is suspected. In the emergency setting, immobilization is essential when fracture is a concern.


For drug-induced torticollis, treatment with diphenhydramine or benztropine is highly effective. For non-drug-related cases, conservative management includes rest, soft cervical collar, physical therapy, massage, local heat, and analgesics. Benzodiazepines may be used for muscle relaxation. Botulinum toxin is the first-line treatment for chronic or non–drug-induced torticollis, although it is typically administered in an outpatient setting.


Patients require admission if there is suspicion of cervical spine fracture, infection, toxic appearance, inability to maintain hydration, or diagnostic uncertainty. Most uncomplicated cases can be managed as outpatients with referral to specialists such as neurologists, orthopedists, or neurosurgeons.


Key clinical pearls include always excluding serious causes such as infection (e.g., retropharyngeal abscess or meningitis), trauma, and central nervous system pathology before attributing symptoms to benign torticollis. Drug-induced dystonia is common and rapidly reversible with appropriate treatment, and failure to recognize life-threatening causes can lead to significant morbidity.

​

Emergency and Acute Medicine – Toothache




Toothache is a common presentation caused by irritation of the nerve endings within the dental pulp, which contains the tooth’s neurovascular supply. Although most causes are odontogenic, pain may also originate from non-dental sources and be referred to the oral cavity via the distribution of the trigeminal nerve.


The most common etiologies are dental in origin. Dental caries, resulting from bacterial demineralization of tooth structures, can progress to pulpitis, which may be reversible or irreversible depending on severity. Reversible pulpitis causes mild inflammation and transient pain, whereas irreversible pulpitis leads to severe, persistent, and poorly localized pain. If untreated, this may progress to a periapical abscess involving necrotic pulp and surrounding tissues. Other dental causes include periodontal disease (gingivitis and periodontitis), periodontal abscess, pericoronitis (often associated with partially erupted wisdom teeth), cracked-tooth syndrome, postextraction complications such as dry socket, and mucosal conditions such as aphthous ulcers or herpetic gingivostomatitis.


Patients typically present with localized or referred tooth pain that may radiate to the jaw, ear, face, eye, or neck. The pain is often exacerbated by chewing, temperature changes, or lying flat. Associated symptoms may include foul taste, bad breath, fever, or facial swelling. A detailed history should include onset, duration, prior treatments, and associated systemic symptoms.


Physical examination should be thorough and systematic. Findings may include visible dental decay, gingival inflammation, swelling, or trismus (reduced mouth opening). The clinician should inspect and palpate oral structures, assess for lymphadenopathy, and evaluate for signs of deep-space infection such as floor-of-mouth swelling or voice changes. Percussion of teeth may reveal tenderness, and examination for fractures, mobility, or missing teeth is essential. Facial and neck examination should assess for cellulitis, warmth, and stiffness.


Diagnosis is primarily clinical. Laboratory tests are generally not required unless there are signs of systemic toxicity or deep-space infection, in which case inflammatory markers and cultures may be considered. Imaging such as panoramic or periapical radiographs may help identify abscesses or fractures, while CT or MRI is reserved for suspected deep infections. Dental nerve blocks can provide both diagnostic and therapeutic benefit in selected cases.


Management focuses on pain control and treatment of the underlying cause. NSAIDs are first-line therapy for uncomplicated dental pain, with opioids reserved for severe cases. Local or regional dental nerve blocks using long-acting anesthetics such as bupivacaine can provide effective relief. If infection is present, antibiotics are indicated, with penicillin as first-line therapy and clindamycin for penicillin-allergic patients or suspected anaerobic infections.


Localized abscesses should be incised, drained, and irrigated, followed by saline rinses and prompt dental follow-up. Most patients can be discharged with appropriate analgesia, antibiotics if indicated, and referral to a dentist or oral surgeon. However, admission is required for serious complications such as deep-space infections (e.g., Ludwig angina), facial cellulitis near the eye, significant trismus, inability to maintain hydration, or systemic toxicity.


Key clinical pearls include recognizing that dental pain can be referred from non-dental sources such as sinusitis, temporomandibular joint disorders, or even cardiac ischemia. Failure to identify deep-space infections can lead to life-threatening complications, so careful assessment is essential. Prompt dental follow-up is critical, as emergency department treatment is only temporizing and does not address the definitive underlying pathology.

​

Emergency and Acute Medicine – Toluene Poisoning




Toluene poisoning results from exposure to a volatile hydrocarbon that is a clear, colorless liquid with a characteristic sweet odor. It is widely used as an organic solvent in products such as paints, thinners, glues, inks, correction fluid, petroleum products, and aerosolized household items. Exposure may occur occupationally or through intentional abuse, particularly among adolescents due to its low cost and easy accessibility. Methods of abuse include sniffing directly from a container, huffing vapors from a soaked cloth, and bagging vapors in a confined space for inhalation.


Toluene is rapidly absorbed through inhalation and readily crosses the blood–brain barrier, achieving high concentrations in the brain. It exerts multiple toxic effects, including central nervous system depression, myocardial sensitization to catecholamines, and disruption of cardiac ion channels, predisposing to dangerous dysrhythmias. It is metabolized in the liver and excreted through the lungs and urine. Toxicity is dose-dependent, ranging from mild impairment at lower concentrations to anesthesia, seizures, and death at very high levels.


Clinically, acute toxicity primarily affects the neurologic, cardiac, pulmonary, and metabolic systems. Patients may present with euphoria, dizziness, ataxia, confusion, or seizures. Cardiac effects are particularly dangerous and include potentially fatal dysrhythmias, especially in the setting of catecholamine surges (“sudden sniffing death”). Pulmonary complications include chemical pneumonitis and pulmonary edema. Metabolic abnormalities are characteristic and include hypokalemia, hypocalcemia, and a hyperchloremic metabolic acidosis due to accumulation of hippuric acid. Gastrointestinal symptoms such as nausea, vomiting, and abdominal pain may occur, and renal effects include distal renal tubular acidosis, hematuria, and proteinuria.


Chronic exposure leads to progressive and often irreversible damage. Neurologic complications include peripheral neuropathy, leukoencephalopathy, cerebellar dysfunction, and cognitive impairment. Cardiac complications may include dilated cardiomyopathy and persistent dysrhythmias. Renal injury may progress to chronic failure, and musculoskeletal complications such as rhabdomyolysis can occur. Chronic abuse is also associated with psychiatric issues and addiction. In pregnancy, chronic exposure has been linked to fetal solvent syndrome, resembling fetal alcohol syndrome with growth restriction and developmental delay.


Diagnosis is primarily clinical, supported by history of exposure and physical findings such as solvent odor, perioral dermatitis, or evidence of inhalant use on clothing or skin. Laboratory evaluation typically reveals electrolyte abnormalities, particularly hypokalemia and metabolic acidosis. Renal function tests, creatine kinase (if rhabdomyolysis is suspected), and liver function tests should be obtained. Urinary hippuric acid may confirm exposure but does not correlate with severity. Imaging studies include ECG to detect dysrhythmias and chest radiography if respiratory symptoms are present.


Management focuses on supportive care and stabilization. Initial priorities include airway, breathing, and circulation, with supplemental oxygen, cardiac monitoring, and intravenous fluids. Sudden cardiac death is a major risk due to myocardial sensitization, so careful monitoring is essential. Dysrhythmias should be treated according to standard protocols, with consideration of β-blockers for tachydysrhythmias. Respiratory status should be monitored closely, and chemical pneumonitis is managed supportively, as steroids are not recommended.


Metabolic abnormalities should be corrected, including cautious repletion of potassium, calcium, and phosphate. Acidosis generally improves with fluid resuscitation. In cases of rhabdomyolysis, aggressive hydration is required to maintain urine output. Gastrointestinal decontamination is generally not useful and may increase the risk of aspiration; activated charcoal is ineffective for hydrocarbons.


Disposition depends on clinical severity. Patients with altered mental status, dysrhythmias, significant metabolic disturbances, renal failure, or rhabdomyolysis require admission. Those who return to baseline mental status and remain stable after 4–6 hours of observation without evidence of complications may be discharged.


Key clinical pearls include the risk of sudden death due to catecholamine-induced dysrhythmias and the importance of monitoring and correcting electrolyte abnormalities. Cardiac complications carry a poor prognosis, and cessation of exposure is the most important long-term intervention. Referral for psychiatric evaluation and substance abuse counseling is essential in cases of intentional or repeated use.

​

Ophthalmology – Branch Retinal Vein Occlusion (BRVO)




Branch retinal vein occlusion (BRVO) is a retinal vascular disorder characterized by obstruction of blood flow in a branch retinal vein, typically at an arteriovenous crossing. It commonly presents with painless, variable vision loss, which may be blurred or distorted. Clinically, BRVO is classified into ischemic and nonischemic types, which differ in severity, prognosis, and risk of complications. It primarily affects individuals over 50 years of age, while pediatric cases are rare and often associated with identifiable systemic causes such as hypercoagulable states.


Epidemiologically, BRVO is the second most common retinal vascular disorder after diabetic retinopathy and is more common than central retinal vein occlusion. Its incidence increases with age, with a 15-year cumulative incidence of approximately 1.8% reported in population studies. The overall prevalence ranges from 0.6% to 1.6%, affecting both men and women equally.


The strongest risk factor for BRVO is systemic hypertension, present in the majority of patients. Other important risk factors include diabetes mellitus, hyperlipidemia, obesity, cardiovascular disease, and hyperviscosity syndromes. In younger patients, evaluation for thrombophilia or systemic disease is essential, as BRVO is less commonly idiopathic in this group.


Pathophysiologically, BRVO is believed to result from mechanical compression of a retinal vein by an adjacent artery at arteriovenous crossing points, where both share a common sheath. This leads to turbulent flow, endothelial injury, and thrombus formation—components of Virchow’s triad. The resulting venous obstruction causes increased hydrostatic pressure, retinal hemorrhage, and capillary leakage. Hypoxia stimulates increased production of vascular endothelial growth factor (VEGF), contributing to macular edema and neovascularization, which are major causes of vision loss.


Patients typically present with sudden or gradual vision loss, depending on the extent and location of involvement. Fundus examination reveals sectoral flame-shaped hemorrhages in the distribution of the affected vein, along with dilated and tortuous vessels. Additional findings may include cotton wool spots, microaneurysms, retinal edema, and, in chronic stages, collateral vessel formation and retinal pigment epithelial changes. The superotemporal quadrant is most commonly affected.


Diagnosis is primarily clinical, supported by imaging. Fluorescein angiography demonstrates delayed venous filling, leakage, and areas of capillary nonperfusion, particularly in ischemic BRVO (defined as greater than five disc areas of nonperfusion). Optical coherence tomography (OCT) is essential for detecting and monitoring macular edema. Laboratory investigations are generally unnecessary in older patients with known vascular risk factors but are important in younger patients to evaluate for systemic or hypercoagulable conditions.


Management focuses on treating complications such as macular edema and neovascularization. First-line therapy includes intravitreal anti-VEGF agents such as bevacizumab, ranibizumab, or dexamethasone implants, which reduce edema and improve visual outcomes. Historically, macular grid laser photocoagulation was used for persistent edema, and it remains an option in selected cases. Panretinal photocoagulation is indicated for neovascular complications but is not used prophylactically. In refractory cases, surgical options such as vitrectomy may be considered.


Patients require close follow-up, typically monthly for the first three months and then at regular intervals, with monitoring using OCT, fluorescein angiography, and visual field testing. Coordination with a primary care physician is important to manage systemic risk factors and prevent recurrence or progression.


The prognosis for BRVO is generally favorable, with about half of patients achieving visual acuity of 20/40 or better. However, outcomes vary depending on the extent of ischemia, presence of macular edema, and development of complications. Conversion from nonischemic to ischemic BRVO can occur, making prognosis unpredictable. Major complications include macular edema, macular ischemia, retinal neovascularization, and vitreous hemorrhage, all of which can significantly impact vision.

​

Ophthalmology – Bartonella Neuroretinitis




Bartonella neuroretinitis is a form of neuroretinitis characterized by optic disc swelling accompanied by a distinctive pattern of hard exudates radiating from the macula in a “macular star” configuration. The most common infectious cause is Bartonella henselae, a gram-negative bacillus associated with cat-scratch disease. While neuroretinitis can result from various infectious and inflammatory conditions, Bartonella infection remains the leading identifiable etiology.


This condition can affect individuals of all ages but is most commonly seen in patients in their third to fourth decades of life. There is no clear gender predilection. A key risk factor is exposure to cats, particularly kittens, as transmission typically occurs through scratches or bites. Other infectious causes of neuroretinitis include syphilis, viral infections, toxoplasmosis, toxocariasis, histoplasmosis, and Lyme disease. Noninfectious causes such as sarcoidosis may also present similarly and should be considered in the differential diagnosis.


Patients typically present with visual complaints such as blurred vision and eye discomfort, often worsened by eye movement. Systemic symptoms may accompany the ocular findings, especially in cases related to cat-scratch disease, and can include fever, malaise, headache, and muscle aches. A detailed history is important, including animal exposure, travel, dietary habits, and sexual history, to help identify potential infectious etiologies.


On examination, visual acuity can range widely from normal to severely reduced, even to light perception in some cases. Common findings include decreased color vision, a relative afferent pupillary defect, and optic disc edema. The hallmark feature is the presence of macular hard exudates arranged in a star pattern around the fovea. Additional findings may include splinter hemorrhages, retinal vascular occlusions, small yellow-white retinal or choroidal infiltrates, and vitreous inflammation. In systemic Bartonella infection, patients may also exhibit lymphadenopathy, arthritis, or neurologic involvement such as meningitis or encephalitis.


Diagnosis is primarily clinical but supported by laboratory and imaging studies. Serologic testing for Bartonella henselae is commonly used, with ELISA being widely available. Testing for other infectious causes should be performed as indicated. Fluorescein angiography typically demonstrates optic disc leakage and staining of peripapillary vessels. Visual field testing often reveals a cecocentral scotoma, which is the most common defect associated with this condition.


The differential diagnosis includes optic neuritis and other forms of optic neuropathy, which may present with similar visual symptoms but lack the characteristic macular star. Identifying the underlying cause is crucial for appropriate management.


Treatment of Bartonella neuroretinitis generally involves antibiotic therapy. First-line treatment for cat-scratch disease includes oral ciprofloxacin, although other antibiotics such as azithromycin, doxycycline, erythromycin, or rifampin may also be used depending on clinical circumstances. Patients should be co-managed with a primary care physician or infectious disease specialist, in addition to close ophthalmologic follow-up.


The prognosis is typically favorable, as Bartonella neuroretinitis is often self-limited. Optic disc swelling usually resolves within 6 to 8 weeks, while macular exudates may take 6 to 12 months to fully resolve. Some patients may experience persistent visual symptoms such as mild blurring or metamorphopsia, and residual optic disc pallor can occur. Recurrence is uncommon. Potential complications include permanent visual loss and systemic complications related to the underlying infectious or inflammatory condition.

​

Ophthalmology – Behçet’s Disease




Behçet’s disease is a multisystem inflammatory disorder characterized by a systemic vasculitis affecting small blood vessels. It classically presents with a triad of recurrent oral aphthous ulcers, genital ulcers, and uveitis, although skin lesions and systemic involvement are also common. The ocular manifestations are particularly important, as they can range from mild anterior uveitis to severe, sight-threatening retinal vasculitis. The disease tends to follow a relapsing-remitting course and can involve multiple organ systems.


Epidemiologically, Behçet’s disease is most prevalent along the historic “Silk Road,” particularly in countries such as Turkey, Japan, the Middle East, and parts of Asia. It most commonly affects young adults between the ages of 25 and 35, although it can occur at any age. While earlier reports suggested a male predominance, more recent data indicate a more equal distribution between sexes. The disease is rare in North America. Genetic predisposition plays a role, with a strong association with the HLA-B51 allele, while environmental or infectious triggers such as streptococcal organisms and viruses have been proposed but not definitively proven.


The pathophysiology involves an abnormal immune response leading to a nonspecific obliterative vasculitis. Dysfunction of lymphocytes and immune regulation results in inflammation and damage to blood vessels throughout the body. This explains the wide range of systemic and ocular manifestations seen in affected patients.


Diagnosis of Behçet’s disease is clinical, as there is no single confirmatory laboratory test. The most widely used criteria require recurrent oral ulcers (at least three times in one year) along with at least two of the following: recurrent genital ulcers, ocular inflammation, skin lesions, or a positive pathergy test. Oral ulcers are the most common feature, occurring in nearly all patients, and appear as painful, well-defined lesions with a red border. Genital ulcers may be painful or painless and often recur. Skin findings include erythema nodosum, acneiform eruptions, and superficial thrombophlebitis.


Ocular involvement occurs in a majority of patients and is a major cause of morbidity. Patients typically present with eye pain, redness, photophobia, and blurred vision. Anterior segment findings include nongranulomatous anterior uveitis, sometimes with a shifting hypopyon, although hypopyon is less common today due to earlier treatment. Posterior segment involvement is more severe and includes retinal vasculitis affecting both arteries and veins, vitreitis, vascular occlusion, and retinal ischemia. These changes can lead to complications such as neovascularization and vision loss. Neuro-ophthalmic findings, including cranial nerve palsies and optic disc edema, may occur in cases with central nervous system involvement.


Evaluation includes a thorough clinical examination and may be supported by laboratory testing. Although routine labs are often nonspecific, tests such as HLA-B51 typing and the pathergy test can support the diagnosis. Imaging studies, particularly fluorescein angiography, are essential in assessing retinal vascular involvement and monitoring disease progression. In cases with suspected neurologic involvement, MRI and cerebrospinal fluid analysis may be required.


Management depends on disease severity and organ involvement. Mild disease may be managed conservatively, but moderate to severe cases—especially those with ocular, neurologic, or vascular involvement—require aggressive immunosuppressive therapy. Systemic corticosteroids are often used initially for rapid control of inflammation, but long-term use necessitates steroid-sparing agents. These include immunosuppressive drugs such as azathioprine, mycophenolate mofetil, cyclosporine, and tacrolimus, as well as cytotoxic agents like cyclophosphamide. Biologic therapies, particularly tumor necrosis factor (TNF) inhibitors such as infliximab and adalimumab, have become increasingly important in controlling severe disease. A multidisciplinary approach involving ophthalmologists, rheumatologists, and other specialists is essential.


Patients with ocular involvement require urgent referral to a uveitis or retinal specialist due to the high risk of vision loss if treatment is delayed. Surgical interventions, such as cataract extraction, may be performed once inflammation is well controlled, while laser photocoagulation may be used to treat retinal neovascularization.


The prognosis of Behçet’s disease has improved significantly with modern immunosuppressive and biologic therapies, although visual outcomes can still be guarded. Without adequate treatment, a high proportion of patients may develop severe visual impairment or blindness. Systemic prognosis is generally favorable in the absence of major complications such as central nervous system involvement or large-vessel disease. Over time, many patients experience longer periods of remission, and disease activity may stabilize after approximately a decade.


Complications primarily relate to chronic inflammation and vascular damage. Ocular complications include cataract, glaucoma, retinal ischemia, neovascularization, vitreous hemorrhage, retinal detachment, and optic nerve damage, all of which can contribute to permanent vision loss.

​