What are the characteristic physical findings of posterior cerebral artery (PCA) stroke?

Updated: Jul 30, 2018
  • Author: Erek K Helseth, MD; Chief Editor: Helmi L Lutsep, MD  more...
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Answer

The most common examination finding is a homonymous visual-field cut, usually a complete hemianopia, caused by a lesion in the contralateral occipital lobe. Macular or central field sparing can occur if the occipital pole remains intact through blood supply from a branch of the middle cerebral artery. Cortical blindness results from bilateral posterior cerebral artery (PCA) infarcts. [7, 10]

Deep or proximal PCA infarcts involve portions of the thalamus and midbrain. Thalamic lesions result in contralateral face and limb sensory loss. The midbrain cerebral peduncle carries corticospinal tract fibers that decussate caudally in the brainstem. A peduncle lesion is associated with contralateral motor weakness. Motor symptoms also are induced by thalamic edema near the internal capsule or a focal lesion in this structure. The posterior aspect of the internal capsule, variably, receives some blood from branches off the proximal PCA.

Large or bilateral PCA infarcts that involve thalamus, temporal, and/or parietal-occipital lobes often result in a spectrum of possible findings (neuropsychologic deterioration and memory, language, or visual-cognitive dysfunction). Prosopagnosia and visual agnosia are representative examples.


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