A 70-year-old hypertensive woman presents with sudden painless vision loss (6/60) in the left eye. Fundus examination reveals a saccular dilatation of a superotemporal arteriole at a second-order bifurcation (marked **A** in the diagram), surrounded by multilayered hemorrhage and lipid exudation in a circinate pattern. OCT shows serous macular detachment. Which of the following best describes the pathophysiology of the focal arterial dilatation marked **A**?
A. Congenital malformation of the superficial capillary plexus presenting as multiple microaneurysms in diabetic retinopathy
B. Proliferative neovascularization from choroidal origin secondary to age-related macular degeneration
C. Benign capillary hemangioma of the retina with progressive enlargement and spontaneous regression
D. Acquired focal dilatation of a major retinal arteriole due to arteriolar wall weakness at arteriovenous crossings, classically in elderly hypertensive women with atherosclerosis and hyperlipidemia
Explanation
Why option 1 is correct
The structure marked A represents a retinal arterial macroaneurysm (RAM), an acquired focal dilatation of a major retinal arteriole. The pathophysiology involves arteriolar wall weakness at arteriovenous crossings with focal aneurysmal bulging. This condition is classically seen in elderly hypertensive women, often with associated atherosclerosis, hyperlipidemia, and diabetes. The clinical presentation—sudden vision loss, saccular dilatation at a second- or third-order bifurcation, multilayered hemorrhage (subretinal, intraretinal, and boat-shaped subhyaloid), and circinate lipid exudation—is pathognomonic for RAM. (Ryan SJ. Retina. 6th ed.)
Why each distractor is wrong
Option 2: Diabetic microaneurysms are multiple, smaller, and occur within the capillary network—not a single saccular dilatation of a major arteriole. They represent a different pathophysiology (capillary occlusion and pericyte loss) and are not associated with the acute hemorrhagic presentation seen here.
Option 3: Choroidal neovascular membrane (CNVM) is a differential diagnosis but arises from the choroid, not the retinal arteriole. It does not present as a focal arterial dilatation at an arteriovenous crossing and is not associated with the characteristic boat-shaped subhyaloid hemorrhage.
Option 4: Capillary hemangiomas are benign vascular hamartomas that present differently—typically as small, red lesions without the acute hemorrhagic and exudative features seen in RAM. They do not cause sudden vision loss or multilayered hemorrhage.
High-YieldNEET PG
RAM = acquired focal arteriolar dilatation at A-V crossings in elderly hypertensive patients; presents with acute hemorrhage (boat-shaped subhyaloid) and circinate lipid exudation; many asymptomatic non-leaking RAMs thrombose spontaneously.
Ryan SJ. Retina. 6th ed.
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