What is Susac syndrome?

Susac syndrome is a rare, autoimmune disease. Autoimmune means that your immune system mistakenly attacks your own tissues. In Susac syndrome, your immune system attacks the smallest blood vessels in your brain, retina (part of the eye), and inner ear. The blood vessels become blocked. Blocked or decreased blood flow through your blood vessels can cause problems in your brain, retina and inner ear.

Other names for the syndrome are: SICRET – small infarctions of the cochlear, retinal and encephalic tissue, and RED-M – microangiopathy with retinopathy, encephalopathy and deafness.

Who is affected by Susac syndrome?

Susac syndrome is rare, but when it occurs it strikes three times as many women as men. It mostly affects people between the ages of 20 and 40, but people outside this age group may rarely be affected.

Is Susac syndrome an inherited condition?

No, there is no evidence that Susac syndrome is inherited (runs in families).

What are the symptoms of Susac syndrome?

Symptoms vary from person to person. Symptoms typically correspond to the area of the body affected.

Brain symptoms (these are the most common first symptoms):

  • Severe headache, often with vomiting.
  • Confusion
  • Problems with thinking, such as short-term memory loss, slow thought processing and reduced ability to solve problems.
  • Slurred speech.
  • Walking difficulties.
  • Changes in personality.
  • Psychological problems such as depression, psychosis, aggression, anxiety or withdrawal.

Eye symptoms:

  • Dark area in part(s) of the visual field.
  • Visual disturbance (described as “a dark shade or curtain drawn over part of my vision”).
  • Loss of peripheral (side) vision.

Inner ear symptoms:

  • Hearing loss.
  • Dizziness (vertigo).
  • Ringing in the ears (tinnitus).

Most people with Susac syndrome do not have symptoms from the brain, eyes, and inner ear at the same time. Presenting symptoms can be from any of the three affected areas, but brain symptoms are the most common first symptom. About 85% of affected individuals experience symptoms from all three areas at some point during their disease course. It may take weeks, months or even years for all body areas to be affected.

What causes Susac syndrome?

Susac syndrome is the result of your own immune system attacking endothelial cells – the cells that line the inner walls of your blood vessels – in your brain, retina and inner ear. When attacked, the endothelial cells swell and can partially or completely shut off blood flow through the vessel. The blockage prevents needed nutrients and oxygen from reaching these areas.

It’s not known what causes your immune system to attack the endothelial cells.

Last reviewed by a Cleveland Clinic medical professional on 11/20/2020.


  • Dorr J, Krautwald S, Wildemann B, et al. Characteristics of Susac syndrome: A review of all reported cases. Nat Rev Neurol 2013 (April 30 online); 9, 307-316. Accessed 11/12/2020.
  • Genetic and Rare Diseases Information Center (GARD). Susac syndrome. Accessed 11/12/2020.
  • Rennebohm R, Asdaghi N, Srivastava S, Gertner E. Guidelines for treatment of Susac syndrome: An update. Int J Stroke 2020;15(5):484-494. Accessed 11/12/2020.
  • Egan RA. Diagnostic criteria and treatment algorithm for Susac Syndrome. J Neuroophthalmol 2019 Mar;39(1):60-67. Accessed 11/12/2020.

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