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NORD is very grateful to John O. Susac, MD, deceased; Robert Rennebohm, MD, Pediatric Rheumatology and Immunology, Cleveland Clinic; and Robert A. Egan, MD, Director of Neuro-Ophthalmology, Oregon Neurology, for the preparation of this report.
Synonyms of Susac's Syndrome
- Susac syndrome
- No subdivisions found.
Susac's syndrome is a rare disorder characterized by three main problems: impaired brain function (encephalopathy), partial or complete blockage (occlusion) of the arteries that supply blood to the retina (branch retinal artery occlusion, or BRAO), and inner ear disease (hearing loss, most notably).
Three main forms of Susac's syndrome have become apparent. In one form, encephalopathy is the main problem. In the second form, BRAO and hearing loss are the main problems, and there is little or no brain disease. In the third form, encephalopathy is the main problem in the beginning, but recurrent episodes of BRAO and hearing loss become the main problem after the encephalopathy goes away.
The encephalopathic form of Susac's syndrome often resolves spontaneously (often going away within 1 years), even without treatment (self-limited); the other forms tend to follow a more prolonged, more chronic course (3-10 years, or more).
Although considered rare, Susac's syndrome is being recognized more often worldwide and its true frequency in the general population is unknown. This is because the disorder may be misdiagnosed as multiple sclerosis.
Susac's syndrome is an autoimmune disease---specifically, an autoimmune endotheliopathy. "Autoimmune" means that a person’s own immune system is mistakenly attacking one's own healthy tissue. An "endotheliopathy" is any disorder that involves injury to the endothelium, which is the thin layer of cells that line the inner walls of blood vessels. In Susac's syndrome, the person's own immune system is mistakenly attacking the endothelial lining of the smallest blood vessels (the capillaries, venules and arterioles) in the brain, retina, and inner ear. When the endothelial cells become injured, they tend to swell, and this endothelial cell swelling plays a key role in the partial or complete occlusion (blockage) of the tiny vessels in the brain, retina and inner ear. This blockage results in decreased blood flow through the vessels and, therefore, decreased delivery of oxygen and nutrients to the brain, retina, and inner ear---causing these three organs to suffer.
Susac's Syndrome Resources
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