An unusual form of measles meningoencephalitis

Two patients are reported with a chronic progressive illness characterized by dementia, ataxia and spasticity. There were no myoclonic jerks and both had normal electroencephalograms (EEG). Pathological findings in three brain biopsies were those of viral meningoencephalitis with perivenous demyelination. Serological data in both patients indicated the presence of a measles virus infection. Intracytoplasmic structures resembling measles virus nucleocapsids were found in the brain biopsy of one patient. Immunofluorescent staining showed antibody in the temporal lobe biopsy of both patients. It is suggested that these patients are examples of a chronic form of measles meningoencephalitis hitherto undescribed.