Retinal Arterio-Arterial Collaterals in Susac Syndrome

Background: The ophthalmic findings of Susac syndrome (SS) consist of visual field defects related to branch retinal artery occlusion (BRAO), and fluorescein angiography (FA) reveals a unique staining pattern. To date, retinal arterial collateral development has been described only in a single patient. Given that the immunopathological process in SS induces retinal ischemia, it is conceivable that abnormal blood vessel development may occur in affected individuals. Methods: This is a retrospective observational study. The medical records including fundus photography and FA of all patients with SS were reviewed, and those with any type of retinal arterial collateral were identified. Results: A total of 11 patients were identified with retinal collaterals. Five were men. Age ranged from 20 to 50 years. Ten patients had arterio-arterial (A-A) collaterals and 1 had arterio-venous (A-V) collaterals, and all had collaterals remote from the optic disc. No collaterals were present at onset of illness and the first developed at 9 months. Conclusions: The literature reveals scant evidence for the association between BRAO and retinal arterial collaterals. Our findings indicate that retinal arterial collaterals in SS are usually A-A and not A-V and may be more common in this disorder than previously believed. Collaterals do not develop early in the disease, and there may be a predilection toward development in men. The chronic inflammatory state of SS may be the stimulus for the development of these arterial collaterals. Address correspondence to Robert A. Egan, MD, Department of Neurology, Rockwood Clinic, 910 W. 5th Avenue, Suite 1000, Spokane, WA 99204; E-mail: Eganr8@gmail.com The authors report no conflicts of interest. © 2018 by North American Neuro-Ophthalmology Society

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