Acute cerebellar ataxia in a child with transient pontine lesions demonstrated by MRI.

A case of acute cerebellar ataxia with discrete signs of pyramidal and tegmental involvement is reported, several days after recovery from an upper respiratory infection of unknown etiology. Magnetic resonance imaging showed transient pontine lesions, disappearing in the convalescence phase. Laboratory tests established the etiologic diagnosis of post-infectious encephalitis. An allergic autoimmune response with subsequent demyelinisation is assumed. The important role of MR-imaging in similar acute syndromes is emphasized.