September 28, 2015: Susac Syndrome
September 28, 2015
First described in 1979 by John Susac at Walter Reed Clinic, Susac syndrome is a rare likely immunologically-mediated illness identified by a clinical triad of encephalopathy, bilateral sensorineural hearing loss, and recurrent branch retinal artery occlusions. Females in the second to fourth decades are classically affected but some case reports of men have also been described. The course is self-limited from 6 months to 5 years and monophasic with fluctuations. The sensorineural hearing loss tends to be for low to medium frequencies and is due to microangiopathy. The encephalopathy is of acute to subacute onset and manifested by confusion, psychiatric disturbance, and cognitive impairment. Unremitting migraine-like headache is common.
MRI of the brain classically shows small multifocal white matter lesions with a predilection for the central fibers of the corpus callosum and sparing of peripheral fibers. Lesions are hyperintense on T2 FLAIR with acute lesions enhancing on T1 post-gadolinium sequences. Up to a third of cases having leptomeningeal enhancement. Fluorescein angiography can identify branch retinal artery occlusions and help with diagnosis. Intravenous methylprednisolone can shorten recovery time of encephalopathy, but there is no reported role for antiplatelet use.
- Susac JO, Hardman JM, Selhorst JB. Microangiopathy of the brain and retina. Neurology 1979; 29: 313-316.
- Susac JO. Susac's syndrome. AJNR Am J Neuroradiol 2004; 25: 351-352.
- Demir M. Case 142: Susac Syndrome. Radiology 2009; 250: 598-602.
Submitted by Sarah Wesley, MD, Department of Neurology, Mount Sinai Beth Israel Medical Center.
Disclosures: Dr. Wesley is a member of the Resident and Fellow Section of Neurology.