Acute disseminated encephalomyelitis (ADEM) is characterized by inflammation in the brain and spinal cord, causing damage to myelin, the protective covering of nerve fibers. This condition typically follows viral or bacterial infections, or in rare cases, vaccination for diseases like measles, mumps, or rubella.
ADEM presents with rapid-onset symptoms resembling encephalitis, including fever, fatigue, headache, nausea, vomiting, and in severe cases, seizures and coma. It can also affect white matter in the brain, resulting in neurological symptoms such as visual loss, weakness leading to paralysis, and difficulties in coordinating voluntary muscle movements, such as walking.
Misdiagnosis of ADEM as a severe initial episode of multiple sclerosis (MS) is not uncommon due to similarities in symptoms caused by white matter injury. However, ADEM typically exhibits symptoms of encephalitis (e.g., fever or coma) alongside those of myelin damage (e.g., visual loss, paralysis), whereas MS lacks encephalitis symptoms. Additionally, ADEM usually manifests as a single episode, whereas MS involves recurrent attacks over time.
Treatment for ADEM involves suppressing brain inflammation using anti-inflammatory medications. High-dose intravenous corticosteroids are administered to alleviate neurological symptoms and prevent further disease progression in the short term.