Mild parkinsonism in persons exposed to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)

In 1982, seven intravenous drug users injected what they thought was heroin and rapidly developed moderate to severe movement disorders indistinguishable from Parkinson's disease. The disorders proved to be permanent. The street drug they injected was found to contain 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). While some similar sort of chemical insult may play a role in the development of idiopathic Parkinson's disease (PD), a key distinction between PD and the ailment suffered by these addicts is that Parkinson's disease begins mildly and progresses slowly. For this reason, an attempt was made to identify drug abusers who might have come in contact with MPTP but who developed only mild symptoms and who therefore did not come to the attention of the medical community. Ultimately, 22 such cases were found and studied. These patients, all of whom were in the right time and place to have come in contact with the MPTP, and who described acute symptoms consistent with this contact, were found to have symptoms very similar to those of mild Parkinson's disease. The symptoms of rigidity, bradykinesia (or slow movement), and postural instability were indistinguishable from those of Parkinson's disease. Only a milder degree of resting tremor distinguished the addicts from the patients with idiopathic Parkinson's disease. This difference may be accounted for by the fact that the average age of the drug users was much lower than that of the Parkinson's patients. Resting tremor is thought, in cases of PD, to be less severe among the young. It remains to be seen if the drug abusers with mild Parkinson's symptoms progress to more serious symptoms with time. The results of this study indicate that at least one toxic agent is capable of causing a symptoms indistinguishable from those of Parkinson's disease. Further study will determine if, like Parkinson's disease, the neurological damage which results from MPTP toxicity progresses with time. (Consumer Summary produced by Reliance Medical Information, Inc.)