What is acute disseminated encephalomyelitis? ADEM is a rare type of autoimmune encephalitis that causes swelling of the brain, spinal cord and sometimes an optic nerve. It is a demyelinating disease, which means it damages the myelin that covers nerve fibers. Experts don't know the exact cause, but the disease often follows a viral or bacterial infection.

Who gets acute disseminated encephalomyelitis? Unlike MS, ADEM more often affects children. About four in five children who get it are younger than 10. Learn about neurologic care at OHSU Doernbecher Children’s Hospital.

Symptoms: Early symptoms of the disease come on rapidly. They include:

• Fever
• Nausea and vomiting
• Blurry or double vision
• Headaches
• Loss of balance
• Weakness or paralysis in the arms or legs
• In serious cases, loss of consciousness or coma

Treatment: The first treatment is usually corticosteroids given by IV to reduce inflammation.

Recovery: Most people begin to recover within days and have a full or almost full recovery within six months. Some cases may cause nerve damage. Long-term effects can include vision loss, weakness or numbness in parts of the body, or problems with thinking or memory.

ADEM and MS: ADEM’s symptoms can be similar to those of MS. It is often misdiagnosed as an early episode of MS. But ADEM most often includes only one attack, while MS is a chronic (ongoing) disease.

Learn more:

• Acute Disseminated Encephalomyelitis Information Page, National Institute of Neurological Disorders and Stroke

What is Susac syndrome? Susac syndrome is a rare disease in which the body’s immune system attacks the inner lining of small blood vessels in the brain, eye and inner ear. The attack causes swelling that blocks or partly blocks blood vessels, disrupting the flow of oxygen and nutrients.

Susac syndrome can cause problems in how the brain, eye and inner ear work. People with Susac syndrome can have one attack or attacks that come and go. Depending on the type, the disease can last about one to three years, or three to 10 or more years

Recovery: Most people recover, and many show little or no long-term effects. Some people have permanent changes such as hearing loss or trouble thinking.

Who gets Susac syndrome? Susac syndrome is twice as common in women. It most often affects people ages 20 to 40.

Symptoms: Signs of Susac syndrome derive from problems with the brain, eye and inner ear. Some people have symptoms in only one or two areas. Others have symptoms in all three areas but not at the same time.

• Brain-related symptoms include:
  • Short-term memory loss
  • Confusion
  • Slow thinking
  • Slurred speech
  • Personality changes
  • Severe headaches, often with vomiting.
• Vision-related symptoms include:
  • A dark area in one part of your visual field
  • Visual disturbances such as loss of side vision or a dark shade drawn over part of your vision
• Inner-ear symptoms include:
  • Hearing loss
  • Dizziness
  • Ringing in your ears

Treatment: Common medications for Susac syndrome suppress the immune system. These medications, called immunosuppressants, may include corticosteroids and a chemotherapy drug called cyclophosphamide.

Susac syndrome and MS: Susac syndrome is sometimes misdiagnosed as atypical MS. Brain scans can look similar to those of MS patients. It’s important to see a team such as ours that can quickly tell the difference. Patients with Susac can see an almost complete recovery if treated early enough.

Learn more:

• Susac Syndrome, National Organization for Rare Disorders
• Susac Syndrome, Genetic and Rare Disease Information Center