Susac syndrome. A differential diagnosis for demyelination.

Susac syndrome is a microangiopathy of unknown origin, probably autoimmune, affecting capillaries and precapillary arterioles of the brain, retina, and inner ear. It is often misdiagnosed as acute disseminated encephalomyelitis or multiple sclerosis. We report the case of a 25-year-old male with Susac syndrome who developed the clinical triad of encephalopathy, visual and hearing problems over the course of a year. The characteristic MRI findings including central corpus callosal involvement and brain infarctions were supported by branch retinal arterial/arteriolar occlusions on fluorescein retinal angiography. Most patients with Susac syndrome will not have the complete clinical triad initially. A very high index of suspicion is required by the clinician and radiologist in patients with any component of the clinical triad so as not to misdiagnose the MRI findings for demyelination. Even if initial ophthalmologic examinations are normal, these patients should be followed up for later development of branch retinal artery occlusions.