The underlying pathologic defect is damage and death of the dopaminergic pigmented neurons of the substantia nigra, the cells of origin of the nigrostriatal pathway. Grossly, there is loss of pigmentation in substantia nigra . Microscopically, the substantia nigra shows neuronal loss and gliosis. Postencephalitic Parkinson s disease is characterized by tangles in patients recovering from 1918 flu pandemic. Other pigmented neurons of the brainstem are also affected.
Treatment includes levodopa and anticholinergic drugs.
Experimental transplants of fetal brain tissue or autologous adrenal tissue have been tried in some cases, but overall the results are not promising. Signs of frontal or temporal lobe degeneration as well as behavioral abnormalities and extrapyramidal symptoms may be present. Very marked neuronal loss and gliosis in areas with ballooned neurons and intracytoplasmic Pick bodies . Symptoms reflect the involvement of the basal ganglia and the neocortex. Many patients show psychotic behavior.