• ADEM is monophasic, which occurs after vaccination or more often after infections such as measles, rubella, chicken pox, herpes zoster, mumps, Mycoplasma pneumoniae or more often after nonspecific URTIs.
It is an immune-mediated demyelinating disease.
• It is seen between the ages of 5-8 on average, it is slightly more common in men.
• There are fever, lethargy, vomiting, weakness, ataxia, headache, seizure and other systemic findings. Patients develop delirium, coma, myelopathy, and focal neurological signs (encephalopathy is typical). Vision loss, cranial neuropathies, ataxia, motor and sensory deficits, incontinence can be seen.
• T2 MRI shows diffuse lesions characterized by edema, inflammation, and demyelination involving the white matter, basal ganglia, thalamus, and brain stem. Sometimes acute hemorrhagic leukoencephalopathy (Hurst's disease) can be seen. Lesions heal completely within 3-12 months, rarely residual gliosis may remain.
• Monocytic and lymphocytic pleocytosis are observed in CSF. Oligoclonal band elevation is observed in 10% of patients.
• PO prednisolone can be given after high-dose IV methylprednisolone in treatment. It also responds well to IVIG therapy. In resistant cases, plasmapheresis, rituximab and cyclophosphamide can be tried.
• If demyelinating occurs again at least 3 months after ADEM, MS should be considered.
