Pimozide Overdose-induced Extrapyramidal Symptoms Mimicking Neuroleptic Malignant Syndrome: A Case Report with Literature Review.
Kaushik Patil, Vinayak Koparde
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Case in brief
A 33-year-old woman with dysthymic disorder, recurrent depression, and obsessive-compulsive disorder presented after four days of rigidity, mutism, psychomotor slowing, and reduced responsiveness. She later disclosed intentional ingestion of approximately 20–30 pimozide tablets four days earlier. Fever, worsening rigidity, tremors, and ankle clonus raised concern for neuroleptic malignant syndrome (NMS), but creatine phosphokinase was only mildly elevated at 523 U/L. Fever resolved with antibiotics, and extrapyramidal symptoms improved with supportive care and levodopa-carbidopa. She subsequently developed aspiration pneumonia and died.
What made this case unusual
Delayed pimozide toxicity presented with severe extrapyramidal symptoms that resembled NMS and was initially suspected to be catatonia; the overdose history emerged only after presentation.
Diagnostic / clinical pearl
In suspected pimozide toxicity, consider delayed, prolonged extrapyramidal effects and establish the ingestion history. Fever and rigidity can mimic NMS, so interpret creatine phosphokinase and the clinical course in context.