Acute disseminated encephalomyelitis.

Acute disseminated encephalomyelitis is an immune-mediated inflammatory and demyelinating disorder of the central nervous system, commonly preceded by an infection. It principally involves the white matter tracts of the cerebral hemispheres, brainstem, optic nerves, and spinal cord. Acute disseminated encephalomyelitis mainly affects children. Clinically, patients present with multifocal neurologic abnormalities reflecting the widespread involvement in central nervous system. Cerebrospinal fluid may be normal or may show a mild pleocytosis with or without elevated protein levels. Magnetic resonance image (MRI) shows multiple demyelinating lesions. The diagnosis of acute disseminated encephalomyelitis requires both multifocal involvement and encephalopathy by consensus criteria. Acute disseminated encephalomyelitis typically has a monophasic course with a favorable prognosis. Multiphasic forms have been reported, resulting in diagnostic difficulties in distinguishing these cases from multiple sclerosis. In addition, many inflammatory disorders may have a similar presentation with frequent occurrence of encephalopathy and should be considered in the differential diagnosis of acute disseminated encephalomyelitis.