Amaurosis Fugax is
Correct Answer: Transient ischemic attack of retina
Description: Ans. a (Transient ischemic attack of retina). (Ref. Basak, Ophthalmology, 2nd ed., 222)AMAUROSIS FUGAX (Transient ischemic attack of the retina)# Because neural tissue has a high rate of metabolism, interruption of blood flow to the retina for more than a few seconds results in transient monocular blindness, a term used interchangeably with amaurosis fugax.# C/f: Patients describe a rapid fading of vision like a curtain descending, sometimes affecting only a portion of the visual field.# Amaurosis fugax usually occurs from an embolus that becomes stuck within a retinal arteriole.# Ophthalmoscopy:- reveals zones of whitened, edematous retina following the distribution of branched retinal arterioles.- Complete occlusion of the central retinal artery produces arrest of blood flow and a milky retina with a cherry-red fovea.- Emboli are composed of either cholesterol (Hollenhorst plaque), calcium, or platelet-fibrin debris.# The most common source is an atherosclerotic plaque in the carotid artery or aorta, although emboli can also arise from the heart-in patients with diseased valves, atrial fibrillation, or wall motion abnormalities.# Impending branch or central retinal vein occlusion can produce prolonged visual obscurations that resemble those described by patients with amaurosis fugax. The veins appear engorged and phlebitic, with numerous retinal hemorrhages. In some patients, venous blood flow recovers spontaneously, while others evolve a frank obstruction with extensive retinal bleeding ("blood and thunder" appearance), infarctionAura of migraine# In a typical attack, a small central disturbance in the field of vision marches toward the periphery, leaving a transient scotoma in its wake. Patients can confuse aura of migraine with amaurosis fugax.# The expanding border of migraine scotoma has a scintillating, dancing, or zig-zag edge, resembling the bastions of a fortified city, hence the term fortification spectra (Teichopsia).Educational points:D/D of "cherry red" spot on fundus# CRAO,# Blunt injury (Berlin's edema of macula),# Tay-Sach's disease,# Niemann-Pick disease,# Sandhoff's disease & quinine anblyopia.# "Cattle-track" appearance is other important feature of CRVO, apart from Hollenhorst plauge.
Category:
Ophthalmology
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