Branch Retinal Artery Occlusion as a presenting sign of Acute Retinal Necrosis: a rare association

Acute retinal necrosis (ARN) is a potentially blinding necrotizing viral retinitis. It starts with one or more foci and spreads circumferentially and involves the posterior pole in the later stages. Vascular occlusions such as branch retinal artery occlusion, central retinal artery occlusion, and central retinal vein occlusion may occur secondary to underlying infectious etiology such as ARN.

An elderly male patient with a history of coronary artery disease was diagnosed with branch retinal artery occlusion (BRAO) in the right eye and referred to the treating cardiologist. Few days later, he complained of diminution of vision in the left eye which made him seek another consultation when he was diagnosed to have ARN in the left eye, encroaching the posterior pole. He was investigated and treated for the same leading to minimal improvement of vision in the left eye possibly due to a delay in the starting of the anti-viral therapy.

We report this case to highlight that occlusive vasculopathy can be a presenting sign of an underlying infectious etiology in any age group. BRAO was a rare presenting sign of ARN in our patient. A thorough peripheral examination is recommended in order to avoid missing infectious pathologies such as ARN which starts from the retinal periphery, progresses fast, and if not managed on time may lead to permanent loss of vision.