Encephalitis lethargica

Encephalitis Lethargica or EL is an infectious disease that was first described by Dr Constantin von Economo in April 1917, and is sometimes referred to as "von Economo's disease". He defined the following different forms of the disease: somnolent-ophthalmoplegic, hyperkinetic, and amyostatic-akinetic. He also described postencephalitic Parkinsonism. Symptoms can emerge years after the original infection. The disease was defined by the following neuropathologic findings: "inflammatory changes in the tegmentum of the midbrain accounting for the sleep disturbance and ocular signs".

The Encephalitis Lethargica disease occurred at the same time and following the aftermath of the infamous Spanish Flu. The film "Awakenings", from 1990, described some patients with this disease.

Disease recognition
The International Classification of Diseases categorizes EL in the category A85.8 "Other specified viral encephalitis". Encephalitis Lethargica has become much rarer over time, with the last study being published in 2012.

Notable studies

 * 2001, ”von Economo encephalitis”
 * 2017, Encephalitis lethargica: 100 years after the epidemic

Learn more

 * 1925, YouTube: Acute Encephalitis Lethargica
 * 1990, iMDB: Awakenings