Neuroleptic malignant syndrome complicating levodopa withdrawal.

OBJECTIVE: To describe a case of neuroleptic malignant syndrome (NMS) resulting from withdrawal of low-dose levodopa therapy for mild Parkinson's disease. CLINICAL FEATURES: Treatment with levodopa, 50 mg, and benserazide, 12.5 mg, three times a day was withdrawn from a 76-year-old woman with mild Parkinson's disease because she was experiencing intermittent confusion. Fever (38.5 degrees C), tachycardia, increased confusion, severe rigidity and generalised stimulus-sensitive myoclonus developed after 12 hours. The creatine kinase level rose to 2058 U/L. INTERVENTION AND OUTCOME: The fever abated with reintroduction of levodopa. Rigidity was slow to resolve and required additional treatment with dantrolene sodium. CONCLUSION: NMS may be precipitated by withdrawal of relatively low doses of levodopa, even in patients with mild Parkinson's disease. Hyperthermia and rigidity in NMS may result from involvement of separate central dopaminergic pathways.