Acute demyelinating encephalomyelitis
The most common triggers, when identified, are viral or bacterial infections including rubeola, rubella, mumps, varicella, Epstein-Barr virus, human herpesvirus 6, influenza, HIV, and Mycoplasma pneumoniae. There have been reports of ADEM following Zika virus infection. Prognosis is variable and outcomes are more favorable in children. Most patients will improve but over 50% will have residual deficits. It is typically a monophasic illness, although relapses can occur.
Acute hemorrhagic encephalomyelitis is a hemorrhagic variant of ADEM with a more rapid onset and progression of neurologic symptoms. It is associated with hemorrhagic demyelinating lesions and carries a worse prognosis.
G04.00 – Acute disseminated encephalitis and encephalomyelitis, unspecified
83942000 – Acute disseminated encephalomyelitis
Differential Diagnosis & Pitfalls