Parkinsonism is a descriptive term meaning having the characteristics of Parkinson's
disease ( tremor, rigidity, akinesia or bradykinesia and postural instability) but
usually not referring to the disease itself. Parkinsonism may be caused by head injury,
encephalitis, syphilis, carbon monoxide poisoning, cerebral arteriosclerosis, use of MPTP
(a synthetic narcotic).
Parkinsonism can also be caused by multiple system atrophy and progressive
supranuclear palsy, and a number of drug side effects produce this appearance.