Encephalitis lethargica (von Economo's encephalitis)

Joseph R. Berger, Joel Vilensky

Research output: Contribution to journalArticle

10 Scopus citations


In the midst of the Great War (World War I), a peculiar neurologic disease swept large parts of the world in an epidemic fashion. The illness, encephalitis lethargica or von Economo's encephalitis, was characterized by both an acute and chronic phase. The former typically arose on the heels of febrile upper respiratory infection and was characterized by somnolence, asthenia, ocular palsies, and a wide variety of movement disorders. The chronic phase was a common, although not invariable, sequela and occurred months to years later. It was most often characterized by parkinsonism, referred to as postencephalitic parkinsonism, and through the middle of the 20th century may have been responsible for as many as one-half of all parkinsonism cases. This disorder differed from idiopathic Parkinson's disease by the presence of oculogyric crises, alterations in sleep cycle, respiratory disturbances, corticospinal tract findings, and its appearance in young persons. Pathologic studies of encephalitis lethargica revealed a polioencephalitis with predominant involvement of the diencephalon and mesencephalon. The precise etiology of this disorder remains a conundrum. Most investigators suspect a viral etiology. An association with the almost concurrently occurring pandemic influenza epidemic has been proposed, but the preponderance of evidence does not fully support that etiology. Sporadic cases of postencephalitic parkinsonism continue to be reported. There is nothing in the history of medicine to compare with the phantasmagoria of disorder manifested in the course of this strange malady Into the maze of contradictory phenomena it seemed almost impossible to read anything like a rationalized order of events which might be termed a disease entity (McKenzie, 1927).

Original languageEnglish
Pages (from-to)745-761
Number of pages17
JournalHandbook of Clinical Neurology
StatePublished - 2014


  • Epidemic encephalitis
  • Oculogyric crisis
  • Postencephalitic parkinsonism
  • Sleeping sickness
  • Von Economo's disease

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology

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