Encephalitis lethargica, also known as Economo's disease is a rare form of encephalitis which is characterized by lethargy, high fever, sore throat, double vision, stupor, immobility, and active at night and asleep during the day.
Symptoms during the severe stage include being in a coma-like state, abnormal eye movements, parkinsonism, muscle pain, upper body weakness, psychosis, and Klazomania. Generally, this diagnosis is given when the symptoms cannot be attributed to any other neurological condition and that the patient also presents with flu-like symptoms, hypersomnia, paralysis of eye muscles, and behavioral changes. This brain-attacking illness leaves patients in a statue-like condition. The cause of this condition is uncertain; however, it has been associated with immune responses, and infections. The treatments are often merely symptomatic which include anti-Parkinson drugs, steroids, and immunomodulating therapies. Encephalitis lethargica was first described by Constantin von Economo, an Austrian neurologist and psychiatrist, and Jean-Rene Cruchet, a French pathologist in 1917.