Acute Disseminated Encephalomyelitis
What is Acute Disseminated Encephalomyelitis?
Acute disseminated encephalomyelitis (ADEM) is a rare demyelinating disease of the central nervous system. A demyelinating disease is characterized by damage to the myelin sheath, which is the protective coating that surrounds nerve fibers. In ADEM, this damage happens as a result of a brief but intense attack of inflammation (swelling) in the brain and spinal cord. This inflammation is believed to be triggered by an immune system response to an infection.
Symptoms of Acute Disseminated Encephalomyelitis
Symptoms depend on the location of the swelling but may include:
- Nausea and vomiting
- Weakness in arms or leg
- Unsteady walk (ataxia)
- Numbness or tingling (sensory changes)
- Trouble with vision, often in both eyes (optic neuritis)
- Trouble swallowing
Treatments for Acute Disseminated Encephalomyelitis
The most common treatment for ADEM is a high dose of corticosteroids administered through an IV for three to five days to reduce inflammation and speed recovery. If there is no response to corticosteroids, a plasma exchange or immunoglobulin therapy may be recommended.
How common is acute disseminated encephalomyelitis?
ADEM is thought to affect one in every 125,000 to 250,000 people in a given year.
Who gets acute disseminated encephalomyelitis?
ADEM is more common in children than in adults, and it appears slightly more often in boys than girls. It affects all ethnic groups.
How is acute disseminated encephalomyelitis diagnosed?
ADEM is sometimes misdiagnosed as a severe first attack of multiple sclerosis, a more common demyelinating disease of the central nervous system. The process of diagnosing ADEM often includes:
- Medical history, including a recent history of infections and vaccinations
- Neurological exam
- Brain and spinal cord MRI scans
- Lumbar puncture to look at spinal fluid
- Blood tests to look for infectious triggers or other conditions that are confused with ADEM