Acute Dystonia After Antipsychotic Initiation
A 24-year-old man with schizophrenia is brought to the emergency department by his family because of sudden onset of severe neck muscle spasms, difficulty swallowing, and protrusion of the tongue. He started haloperidol 5 mg twice daily 2 days ago for an acute psychotic episode. He has no history of neurological disease and takes no other medications. On examination, he is anxious, has torticollis, and is unable to close his mouth. Vital signs are stable. The emergency physician is considering treatment options.
1. What is the most likely diagnosis, and what is the first-line treatment?
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The most likely diagnosis is acute dystonia, a common extrapyramidal side effect of high-potency antipsychotics like haloperidol, occurring within days of initiation. First-line treatment is an anticholinergic agent: intramuscular or intravenous biperiden 5 mg or diphenhydramine 50 mg. If symptoms persist, repeat after 30 minutes. Alternatively, benztropine 1-2 mg IM/IV. After relief, continue oral anticholinergic prophylaxis (e.g., biperiden 2 mg twice daily) for the duration of antipsychotic therapy, or consider switching to a lower-potency antipsychotic. Monitor for airway compromise.
2. How would you adjust the patient's antipsychotic regimen to prevent recurrence?
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To prevent recurrence, consider reducing the haloperidol dose or switching to a second-generation antipsychotic with lower extrapyramidal risk (e.g., quetiapine, olanzapine, risperidone). If haloperidol must be continued, add prophylactic anticholinergic therapy (e.g., biperiden 2 mg twice daily). Educate the patient and family about the risk of dystonia and the need to seek immediate care if symptoms recur. Ensure adherence and regular follow-up. Monitor for other extrapyramidal symptoms such as parkinsonism and akathisia.