A 56-year-old woman is brought to the emergency department with sudden onset of headache and partial loss of vision. She has a 3-year history of atrial fibrillation. Physical examination shows a visual field defect involving the black areas illustrated below. This patient most likely has occlusion of which of the following arteries?

Question

A 56-year-old woman is brought to the emergency department with sudden onset of headache and partial loss of vision.  She has a 3-year history of atrial fibrillation.  Physical examination shows a visual field defect involving the black areas illustrated below.  This patient most likely has occlusion of which of the following arteries?

Quizplus · Accepted Answer

11ec160b_35d3_d8ea_9249_034041210a51_MD0001_00 The described vision defect is consistent with an occlusion of the posterior cerebral artery (PCA), most likely from an embolic event given this patient's history of atrial fibrillation. The PCA supplies the occipital lobe, which contains the striate or primary visual cortex. The striate cortex of each hemisphere receives information about the contralateral visual field from the ipsilateral lateral geniculate nucleus via the optic radiation. Specifically, the cuneus gyrus of the striate cortex receives information from the upper retina (lower visual field), while the lingual gyrus of the striate cortex receives information from the lower retina (upper visual field). Occlusion of the PCA leads to ischemic injury to the ipsilateral striate cortex, producing a contralateral homonymous hemianopia with macular sparing. The macula is spared because collateral blood is supplied by the middle cerebral artery to the occipital pole, which processes central visual information. Unilateral infarcts involving only the cuneus gyrus or the lingual gyrus will produce a lower or upper quadrantanopia, respectively. (Choice A) Anterior cerebral artery occlusion manifests as contralateral weakness that predominantly affects the lower extremity. (Choice B) Occlusion of the central retinal artery leads to sudden, painless, and complete loss of vision in the affected eye. (Choice C) Middle cerebral artery stroke is characterized by contralateral motor and sensory deficits (more pronounced in the upper than lower limb) and homonymous hemianopia with macular involvement. (Choice E) Occlusion of the posterior inferior cerebellar artery leads to lateral medullary (Wallenberg) syndrome. It is characterized by contralateral loss of pain and temperature sensation; ipsilateral deficits of CN V, VIII, IX, X, and XI; and Horner's syndrome. Educational objective: Lesions of the occipital cortex (eg, posterior cerebral artery occlusion) can produce contralateral homonymous hemianopia with macular sparing.

A 56-Year-Old Woman Is Brought to the Emergency Department with Sudden