Multiphasic acute disseminated encephalomyelitis and differential with early onset multiple sclerosis.

Multiple sclerosis is considered the most frequent demyelinating disorder of the Central Nervous System (CNS) among young adults, yet is very rare before 10 years old. Acute disseminated encephalomyelitis is a monophasic, polysymptomatic disorder that involves the CNS white matter with demyelinating lesions, which usually occurs after systemic viral infections. These two demyelinating diseases can present initially as an acute focal neurological syndrome and they can be difficult to distinguish. We describe a case of a nine-year-old girl that presented initially with dysphonia, gait ataxia, eyelid myokymia and brainstem disturbances. This was her second episode; the first episode was at the age of four years old. She recovered without neurological sequelae. The brain magnetic resonance imaging (MRI) demonstrated multiple demyelinating lesions in the white matter, cortical regions of the frontal lobe, periventricular distribution, internal capsule, corpus callosum and cerebellum. The purpose of the presentation of this case was to highlight the similarities between these two entities, since the clinical picture and neuroimaging are difficult to distinguish, mainly in relation to the first episode.