September 11, 2013: Quadrantanopia: Parietal vs Occipital
September 11, 2013
An inferior quadrantopia can be caused by both a parietal MCA infarct or a PCA infarct affecting the superior bank of the calcarine fissure of the occipital lobe. As most of us know, an occipital lobe infarct largely spares the macula. There are other clues on examination that separate the two etiologies.
In parietal visual loss, patients are generally unaware of their deficit and have associated visual neglect. In contrast, patients with PCA infarcts are usually aware of their deficit and do not have visual neglect. Patients with occipital infarcts are able to bisect lines scattered throughout a page and can describe a full picture placed before them, by moving the image to the preserved visual field. These patients also have intact optokinetic nystagmus in contrast to patients with parietal lobe infarcts
1. Caplan L. Caplan's Stroke: A Clinical Approach (4th ed). Philadelphia: Saunders/ Elsevier; 2009:258-290 (Chapter 7).
Submitted by Joseph Zachariah, MD, Case Western Reserve, UH Hospitals, Cleveland, OH
Dr. Zachariah reports no disclosures.