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Failure of recognition of drug-induced parkinsonism in the elderly CD Esper, SA Factor Movement Disorders 2008;23:401-404 Drug-induced parkinsonism (DIP) is often misdiagnosed in elderly patients, even by neurologists, and may lead to years of inappropriate treatment, according to this study. The authors performed a chart review of 354 patients with newly identified parkinsonism presenting to a movement disorders clinic over a two-year period. DIP was considered in patients with subacute onset of at least 2 of 4 cardinal motor features of PD that began while the patient was on a dopamine blocking agent. Agents raising suspicion included typical antipsychotics, atypical antipsychotics, and metoclopramide. Of 354 patients presenting with parkinsonism, 24 (6.8%) patients met the criteria for DIP. Drugs responsible included: Atypical antipsychotics 11 Olanzapine 6 Risperidone 3 Aripiprazole 2 Metoclopramide 5 Typical antipsychotics 2 Antipsychotic plus meto. 2 Amoxapine 2 Only 1 patient arrived with the correct diagnosis from the referring center, although 7 more had discontinued the offending medication. PD was diagnosed by the referring center in 11 cases, and were receiving anti-PD treatment. Three patients were being treated for essential tremor. Nineteen of 24 patients had been seen by a neurologist prior to referral. Time to diagnosis of DIP averaged 1.8 years. Seventeen patients were followed after cessation of the offending medication. Results showed: Condition N mean duration of follow-up Total remission 10 10.1 months Significant improvement 3 8.6 months Modest improvement 3 13.2 months No change 1 9 months The potential for a protracted recovery may be underrecognized, the authors say. Prior to referral, 1 patient had discontinued medication for 2 weeks, but with no change in his condition, he was diagnosed with PD. The authors note the following features that may raise the suspicion of DIP: . Subacute onset . Bilateral symptoms from the outset . Orofacial dyskinesias . Prior or current treatment with a dopamine blocking agent . Resting tremor is not an exclusion criterion "Recent studies have demonstrated that [atypical antipsychotics] definitely worsen parkinsonism in PD, and it is clear from our study and others that these drugs can also be a primary cause of parkinsonism," the authors note. An E-MOVE report on the ability of atypical antipsychotics to cause parkinsonism is archived HERE. http://www.mdvu.org/emove/article.asp?ID=847