A disease of the central nervous system marked mainly by pronounced somnolence (lethargy), myalgias, fever, stupor, ophthalmoplegia, and paresis. Both sexes affected, onset at all ages. Febrile onset. he clinical picture is often dominated by headache, dizziness, fatigue, severe muscle pain, choreiform movements, rigidity and tenderness. Most patients recovering from the disease develop Parkinsonism and personality changes with disorder of behaviour. The condition first occurred during World War and by 1921 it had reached epidemic proportions in most European countries and in North America. At first, many confused encephalitis lethargica with the "Spanish flu". The epidemic lasted until 1926. A similar epidemic occurred in Akureyri, Iceland, in 1948-1949, and since then some isolated outbreaks have been reported in cities in England, Germany, and in New York State. Jean René Cruchet (1875-1959) first noted the disease in the winter of 1915-16 in French soldiers in Verdun, and in the spring of 1915 a few cases were seen in Rumania. Emil Redlich (1866-1930) suspected that this disorder and Redlich's syndrome were variants of the same entity. The disease is now considered extinct. The aetiological agent was never identified.
- J. R. Cruchet, Moutier, Calmettes
Quarante cas d'encéphalo-myélite subaiguë.
Bulletins et Mémoires de la Société Médicale des Hôpitaux de Paris, April 27, 1917, 3 sér. 41: 614-616.
Cruchet's account of epidemic encephalitis preceded that of von Economo by 13 days.
- K. von Economo:
Encepahlitis lethargica. Wiener klinische Wochenschrift, May 10, 1917, 30: 581-585.
Die Encephalitis lethargica. Leipzig and Vienna, Franz Deuticke, 1918.