Japanese encephalitis - serial CT findings and neuropathology in an autopsy case.

The patient was a 17-year-old man, who developed Japanese encephalitis in the autumn of 1990 in Japan. He was admitted to our hospital 4 days after onset because of consciousness disturbance. On admission, neurological examination demonstrated left hemiparesis, neck stiffness, and Kernig's sign. He developed generalized tonico-clonic seizure, and required a respirator on the next day of admission. Brain CT 10 days after onset demonstrated hypodensities in the right hippocampus, and the CT obtained 39 days after onset showed whole brain atrophy and hypodensities in the anterior portion of the bilateral thalamus. He died 40 days after onset. Postmortem examination demonstrated perivascular and parenchymal infiltration of lymphocytes and macrophages, proliferation of microglia and astrocytes, and necrosis in the gray matter of the brain. Involvement of the hippocampus and thalamus on CT seemed to reflect the severe lesions characterized by cellular infiltration and necrosis. We discussed for the first time the correlation of CT and neuropathological findings in a patient with Japanese encephalitis.