Today Dr. Wurzburger presented a fascinating case of a young woman with recent travel to Central America and otherwise no significant past medical history who presented with subacute progressive headaches, gait instability, and eventually florid encephalopathy, found to have hearing loss and vision loss as well as a negative infectious and autoimmune work-up, consistent with a diagnosis of Susac Syndrome.
If you’re like me, and can never remember long mnemonics, try distilling it down to “MIST”. Think altered mental status -> brain fog -> MIST.
M- Metabolic (medications, electrolytes, endocrinopathies)
I- Infection, Inflammation, Immune-related
S- Structural (malignancy, seizures, strokes, intracranial hemorrhage)
Never heard of Susac Syndrome?! You are not alone! There were only ~300 reported cases as of 2013 worldwide!
Susac Syndrome is a rare disorder characterized by the triad of subacute encephalopathy, sensorineural hearing loss, and vision loss due to branch retinal artery occlusions. It is often misdiagnosed as multiple sclerosis. It is theorized to be an autoimmune process against the microvascular endothelium, resulting in a microangiopathy. The diagnosis is made clinically, with the support of a brain MRI involving the corpus callosum. At this time, early aggressive immunosuppressive medications and treatments (steroids, IVIG, PLEX), have proven to have variable results, but possibly some benefit. Evidence-based treatments are obviously quite limited by the extreme rarity of the diagnosis.