In 1919 Mount Sinai researchers Leo Loewe and Israel Strauss described the first experimental transmission of encephalitis lethargica, or acute epidemic encephalitis1, a disease first named in 1917 by the Austrian von Economo. This disease had a brief moment of intense interest, but then disappeared by the 1940s. Mount Sinai researchers treated many cases and were involved in the early efforts to describe its causation. This was part of a larger, really New York based fascination with the disease. This story is well told in a 2004 article by Kenton Kroker2, who uses epidemic encephalitis as a way to look at how the field of neurology was trying to re-define itself as the medical world became focused less on signs and symptoms and more on laboratory proof.
Mount Sinai's involvement can be seen in articles on encephalitis lethargica (EL) by Isador Abrahamson, Associate Neurologist and chief of clinic from 1904-19; Leo Loewe, who was an Intern and then a Research Fellow; and Israel Strauss, a Resident who went on to become Director of our Department of Neurology from 1925-38 and was the founder of Hillside Hospital in Queens. William Thalheimer, a former member of Mount Sinai's house staff, had a role in confirming Loewe and Strauss' research. A new medical organization, the Association for Research in Nervous and Mental Diseases, as one of its first actions formed a group to study this disease and provide a consensus document on what was known3. Involved in that publication was Dr. Strauss, as well as Bernard Sachs, then Director of Mount Sinai's Department of Neurology and known today for Tay-Sachs disease. Mount Sinai Hospital's own annual reports from 1919 into the early 1920s include information on our doctors' efforts in this area.
Research here on epidemic encephalitis seems to have withered over the 1920s. Simon Flexner, then at Rockefeller University, could not replicate Loewe and Strauss' findings, although it was replicated in Europe and by Thalheimer in Milwaukee. Loewe left the staff and Strauss turned to new topics. Over the 1920s and 30s, the exact nature of epidemic encephalitis became less clear, and it fell by the wayside as a diagnosis. Today, encephalitis lethargica is described as: "a CNS disorder that manifests with lethargy sleep cycle disturbances, extrapyramidal symptomatology, neuropsychiatric manifestations, ocular features and cardio-respiratory abnormalities.4" A quick search of PubMed today will bring up 44 articles on the entity from 2005-2011. As noted in a 2009 study: "Although there have been no reported outbreaks of EL recently, a number of reports show that cases of EL are still encountered regularly.4"
1 Loewe, L and Strauss, I. “Etiology of epidemic (lethargic) encephalitis. Preliminary note.” JAMA, 1919, 73: 1056-57.
2 Kroker K. Epidemic encephalitis and American neurology, 1919-1940. Bull Hist Med 2004 Spring;78(1):108-47.
3 Acute Epidemic Encephalitis (Lethargic Encephalitis): An Investigation by the Association for Research in Nervous and Mental Diseases; Report of the Papers and Discussions at the Meeting of the Association, New York City, December 28th and 29th, 1920. New York: Paul P. Hoeber 1921.
4 Lopez-Alberola R, Georgiou M, Sfakianakis GN, Singer C, Papapetropoulos S. Contemporary Encephalitis Lethargica: phenotype, laboratory findings and treatment outcomes. J Neurol. 2009 Mar;256(3):396-404.