Herpes simplex brainstem encephalitis with a relapsing course.

We report a patient with a relapsing form of acute brainstem encephalitis. Pathological examination demonstrated necrotizing encephalitis in the cerebral cortex and, more pronounced, throughout the diencephalon, as well as in the pes pontis. Neurons and glial cells in the cerebral cortex and brainstem contained herpesvirus antigens. The clinical interrelationship of brainstem encephalitis, Miller Fisher syndrome and Landry-Guillain-Barré syndrome is discussed.