Ophthalmology · Retinal Vascular Disorders
The facts most likely to be tested
Patients present with sudden, painless, unilateral vision loss often upon waking.
Funduscopic examination reveals the classic blood and thunder appearance characterized by diffuse retinal hemorrhages.
Key findings include dilated, tortuous retinal veins and cotton-wool spots throughout the fundus.
The primary underlying risk factor is hypertension, followed by hypercoagulable states and glaucoma.
Macular edema is the most common cause of vision loss associated with this condition.
Neovascularization of the iris, or rubeosis iridis, is a serious complication that can lead to neovascular glaucoma.
Initial management involves panretinal photocoagulation for neovascularization and intravitreal anti-VEGF injections for macular edema.
Vignette unlocked
A 68-year-old male with a history of poorly controlled hypertension presents to the clinic complaining of sudden, painless vision loss in his right eye that he noticed upon waking this morning. On physical exam, visual acuity is 20/200 in the right eye and 20/20 in the left. Funduscopic examination of the right eye reveals diffuse retinal hemorrhages, dilated and tortuous retinal veins, and multiple cotton-wool spots.
What is the most likely diagnosis?
Central retinal vein occlusion (CRVO)
The vignette describes the classic 'blood and thunder' funduscopic appearance of CRVO, which is characterized by diffuse hemorrhages and dilated veins resulting from venous outflow obstruction.
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High yield triage
Etiology / Epidemiology
Associated with hypertension, diabetes, and glaucoma. Often caused by thrombus formation at the level of the lamina cribrosa.
Clinical Manifestations
Painless, sudden monocular vision loss. Fundoscopy reveals blood and thunder appearance with diffuse retinal hemorrhages.
Diagnosis
Clinical diagnosis confirmed by fundoscopy. Fluorescein angiography is the gold standard to assess for ischemia.
Treatment
Manage underlying risk factors. Intravitreal anti-VEGF agents (e.g., ranibizumab) are first-line for macular edema. Avoid steroids if infection present.
Prognosis
Risk of neovascular glaucoma (90-day glaucoma). Requires frequent monitoring for neovascularization.
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Epidemiology & Etiology
Primarily affects patients >50 years old with underlying vascular disease. Hypertension is the most significant systemic risk factor. Elevated intraocular pressure, such as in open-angle glaucoma, increases risk by causing venous stasis.
Pertinent Anatomy
The central retinal vein exits the eye through the lamina cribrosa, a narrow anatomical bottleneck. This site is highly susceptible to compression and thrombus formation due to shared adventitial sheaths with the central retinal artery.
Pathophysiology
Thrombosis leads to venous outflow obstruction, causing increased hydrostatic pressure and capillary rupture. This results in extensive retinal hemorrhages, cotton-wool spots, and optic disc edema. Ischemia triggers the release of VEGF, promoting pathological neovascularization.
Clinical Manifestations
Patients present with acute, painless, unilateral vision loss, often upon waking. Fundoscopy shows the classic blood and thunder appearance: diffuse retinal hemorrhages, dilated tortuous veins, and disc swelling. Red flag: development of iris neovascularization indicates impending neovascular glaucoma.
Diagnosis
Diagnosis is primarily clinical via dilated fundus examination. Fluorescein angiography is the gold standard to differentiate between ischemic and non-ischemic types. Ischemic CRVO is defined by >10 disc areas of non-perfusion.
Treatment
Treatment focuses on managing macular edema and preventing neovascularization. Intravitreal anti-VEGF agents are the first-line therapy. Contraindications include active ocular infection or severe uncontrolled systemic hypertension. Panretinal photocoagulation is reserved for patients who develop neovascularization.
Prognosis
Visual prognosis is guarded, especially in ischemic cases. Patients are at high risk for neovascular glaucoma (the 90-day glaucoma), requiring close follow-up for the first 3-6 months.
Differential Diagnosis
Central Retinal Artery Occlusion: presents with a cherry-red spot and pale retina
Diabetic Retinopathy: usually bilateral and associated with microaneurysms
Ocular Ischemic Syndrome: presents with mid-peripheral hemorrhages and low carotid flow
Retinal Vein Branch Occlusion: hemorrhages limited to one quadrant of the retina
Papilledema: bilateral disc swelling usually associated with increased intracranial pressure