[Delayed acute measles encephalitis].

Delayed acute encephalitis is a rare complication of measles that may occur either in immunodepressed patients or in patients without overt immunodepression. In the present series of 8 cases, diagnosis was made on CSF/serum measles antibody titre and/or intranuclear paramyxovirus nucleocapsides identified by electron microscopy in the central nervous system cells. The disease is characterized by the association of focal defects (monoparesis, hemiparesis, aphasia, a.s.o.) with periodic myoclonic jerks without major impairment of consciousness. The encephalitis lasted 2 to 4 weeks and 3 patients died. With the exception of 1 case, all the patients had severe sequelae after a follow-up of 1 to 9 years. The EEG showed diffuse polymorphous delta waves, with a predominance on the side opposite to the myoclonias and pseudoperiodic complexes in all cases. CT scan was abnormal in 4 of 6 cases, showing hypodense areas. Antiviral or immunogenic therapeutic trials were administered to 5 patients without clear improvement. Sensitive methods of antibody dosage seem to be useful for the early diagnosis of the disease.