A contemporary case of encephalitis lethargica

We present a clinicopathological report of a recent fatal case of a 27-year-old woman whom we consider to have had encephalitis lethargica. Clinical features of note were a presentation with vertigo, persistent vomiting and sleep disturbance including marked daytime somnolence and vivid nightmares. On examination, she had impaired slow pursuit vertical eye movements, dysarthria, an expressionless face and slow tongue movements. She went on to develop gross supranuclear gaze palsy, neck rigidity, bradykinesia, blepharospasm, profound somnolence and anarthria but no tremor, weakness or impairment of cognition. She died after an illness lasting 12 months. On investigation, the cerebrospinal fluid was found to contain a very high level of IgG with oligoclonal bands but no cells. Post-mortem examination revealed an active encephalitis, mainly centered on the upper brainstem and diencephalon with extensive Purkinje cell loss and marked plasma cell infiltrates and morula cells. No virus was recovered.