Brain Pathology Case of the Month - March 2011



Survivors of the first wave of encephalitis lethargica (1917-1919) are now very rare all over the world. 40% of patients died during the acute phase of the disease. Extrapyramidal syndromes could occur in survivors just after acute phase or even several years later, in association with catatonia, obsessive-compulsive troubles, or oculogyric crises. Despite the epidemic of lethargic encephalitis occurred simultaneously with the "Spanish" influenza pandemic, a link between the two disease was suspected, but disputed by Von Economo himself (5). Recent examination of archival tissue samples, using modern molecular biology techniques, failed to indentify the influenza virus in the brain of the victims (4). Post encephalitic Parkinsonism may be mediated by auto-immune processes. In post encephalitic Parkinsonism patients, subcortical neurofibrillary tangles distribution is quite similar to progressive supranuclear palsy. They can also involve the hippocampus, the entorhinal cortex and also the temporal, frontal and insular cortices (3). But the biochemical profile of aggregated tau is the same of Alzheimer's disease: 3 bands at 60, 64 and 69 kDa (1). Tufted astrocytes were already observed, as well as astrocytic plaques (3). The full clinical, neuropsychological and neuro-imaging data of our patient were already described (2). The relatively low amount of tau-positive lesions could explain the long lasting and benign course of Parkinsonism in our patient.


  1. Buee-Scherrer V, Buee L, Leveugle B, Perl DP, Vermersch P, Hof PR, Delacourte A (1997) Pathological tau proteins in postencephalitic parkinsonism: comparison with Alzheimer's disease and other neurodegenerative disorders. Ann Neurol.42(3):356-9.
  2. Caparros-Lefebvre D, Cabaret M, Godefroy O, Steinling M, Remy P, Samson Y, Petit H (1998) PET study and neuropsychological assessment of a long-lasting post-encephalitic parkinsonism. J Neural Transm.105:489-95.
  3. Henry JM, Jellinger KA (2003) Postencephalitic Parkinsonism. In: Neurodegeneration: the molecular pathology of dementia and movement disorders, Dickson D, (ed.), pp. 145-9, ISN Neuropath Press: Basel.
  4. Reid AH, McCall S, Henry JM, Taubenberger JK (2001) Experimenting on the past: the enigma of von Economo's encephalitis lethargica. J Neuropathol Exp Neurol.60(7):663-70.
  5. von Economo C (1917) Encephalitis Lethargica. Wiener Klinishe Wochenschrift.30:581-5.

Contributed by Vincent Deramecourt, MD, PhD, Claude-Alain Maurage, MD, PhD, Nicolas Sergeant, PhD, Valérie Buée-Scherrer, PhD, Luc Buée, PhD, Luc Defebvre, MD, PhD

International Society of Neuropathology