Encephalitis lethargica or von Economo disease is an atypical form of encephalitis.
The cause of encephalitis lethargica is unknown. Between 1917 to 1928, an epidemic of encephalitis lethargica spread throughout the world, but no recurrence of the epidemic has since been reported, though isolated cases continue to occur.
The disease is characterized by:
In acute cases, patients may enter coma. Patients may also experience:
Postencephalitic Parkinson's disease may develop after a bout of encephalitis-sometimes as long as a year after the illness.
The course of encephalitis lethargica varies depending upon complications or accompanying disorders.
Treatment for encephalitis lethargica is symptomatic. Levodopa and other antiparkinson drugs often produce dramatic responses.