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post-encephalitic parkinsonism
Etiology:
1) unknown, ? viral (Spanish flu of 1918?, H1N1 influenza A virus?)
2) occasionally occurred following encephalitis lethargica
- interval of months to years Epidemmiology:
- extremely rare
Pathology:
- multisystem neuronal degeneration & cell loss, with
- gliosis in many brainstem nuclei, including substantia nigra & locus ceruleus
- neurofibrillary tangles in
- residual neurons in many subcortical nuclei
- hippocampus, entorhinal cortex, frontal cortec & insular cortex
- distribution differs from that found in Alzheimer's disease
- clinical features referable mainly to the extrapyramidal & oculomotor systems & cognitive deterioration
Clinical manifestations:
- bradykinesia, rigidity, hypomimia (masked facies)
- postural instability, gait disorders with falls
- sialorrhea
- ohthalmoplegia & oculogyric crises
- elderly may heve continuous deterioration of motor function with dysphagia, incontinence, L-Dopa induced psychoses, dystonia, & cognitive impairment Differential dignosis:
- Parkinson's disease, Parkinson's dementia
Management:
- variable response to Sinemet
Interactions
disease interactions
General
parkinsonism
Properties
PATHOLOGY: neurofibrillary tangle
SITE: substantia nigra
cerebral cortex
basal ganglia
hypothalamus
thalamus
neuronal degeneration
SITE: substantia nigra
oculomotor nucleus
References
- Greenfield's Neuropathology, 5th ed., 1992 p.383, 997-8
- Alzheimer Europe
Postencephalitic Parkinsonism (PEP)
https://www.alzheimer-europe.org/Dementia/Other-forms-of-dementia/Infectious-diseases/Postencephalitic-Parkinsonism-PEP