Encephalitis lethargica. What is still wrong?

Abstract

Encephalitis lethargica developed in epidemic from 1919 to 1926 in Europe and throughout the world. From the clinical point of view, the disturbances of consciousness and alertness and the possible outcomes of a postencephalitic Parkinsonism has attracted much attention. For a long time, it was thought that such a disease may still occur sporadically. In this review, the authors examined historical and current pictures of epidemics that may be related to Encephalitis lethargica. The previous Nona and Russian Influenza exhibited frequent neurological symptoms. The Spanish flu, formerly related to Encephalitis lethargica, would appear an epidemic that had its development in a partially overlapping period. The current pandemic linked to COVID-19 sometimes has aspects that can resemble Encephalitis lethargica. Based on historical analysis and the more recent immunological data, it could be suggested that Encephalitis lethargica was an autoimmune encephalitis that arose in a secondary form to the action of a viral agent. It cannot be ruled out that this agent was a coronavirus. From the nosological point of view, the term Encephalitis lethargica should be abolished in designating autoimmune encephalitis pictures that run sporadically.

An Unwanted but Long-Known Company: Post-Viral Symptoms in the Context of Past Pandemics in Switzerland (and Beyond)

“…In the early 1890 s, several cases were also reported in Switzerland of people falling into a deep sleep, sometimes lasting for days, shortly after having contracted the flu (see the section on sleeping sickness below) [ 37 ]. As this phenomenon seemed to be spreading at the same time as an epidemic in some regions of Italy (the disease was called “Nona”) [ 38 ], Swiss newspapers feared that Switzerland might also be affected by this next epidemic (which apparently did not happen to the same extent) ( Figure 3 ).…”