Atypical demyelinating disease.

A 17 year old girl died after an illness characterized by progressive mental deterioration and severe myoclonic jerks. Extensive pathological, virological, and immunological studies failed to support the diagnosis of subacute sclerosing panencephalitis but were compatible with disseminated demyelinating disease. The spinal fluid was positive for measles virus antibodies when examined by the fluorescent antibody technique, by complement fixation, and by haemagglutination inhibition tests, but the antibody titres were not high. The concentration of vaccinia antibody in the serum was consistent with that found in the general population and none was detected in the spinal fluid. Animal and tissue culture studies failed to disclose a viral agent, but pathological sections revealed perivascular cellular infiltration, demyelination, rare inclusion bodies, and multinucleated giant cells. Although these studies were not definitive, a record of procedures used and results obtained, both positive and negative, may be helpful to other investigators interested in defining more accurately the clinical features and the pathogenesis of these diseases.