Acute Dystonia

Case Presentation

A 7-year-old boy was brought to our emergency department, reporting having a seizure. Upon his arrival, he had a low-grade fever (temperature of 37.5°C) and tachycardia (heart rate of 110 beats per minute). The patient’s consciousness was clear and alert. His head was twisting toward left side with extended neck. Bilateral limbs, especially the left arm and leg, were stiff in decerebrate posture ( Fig. 1 ). Following our instructions, he could move both arms and legs (Video 1).

Fig. 1 . Patient’s head was twisting toward left side with extended neck. Bilateral limbs, especially the left arm and leg, were stiff in decerebrate posture.

Video 1. Acute dystonia.

Download video file ^{(8.1MB, mp4)}

[The video is available at http://doi.org/10.6705/j.jacme.202303_13(1).0007 .]

Questions

1. Was this boy having a seizure?

2. What is the most important history you would like to know?

3. How should he be managed at the emergency department?

Answers

1. No, although this boy’s head was twisting toward the left side and his limbs were stiff, his consciousness was clear and was able to follow instructions. The best description for his presentation is acute dystonia.

2. Medical history, especially the medicine he took recently. As acute dystonia is a common presentation of drug-induced extrapyramidal symptoms (EPSs), it is crucial to understand patient’s medication before one makes the diagnosis. According to his parent, the patient suffered from acute gastroenteritis and had been taking medication for 2 days. His medications included mefenamic acid, simethicone, and metoclopramide.

3. Supportive measures should be provided immediately if indicated, such as oxygen, intravenous fluid, and monitors. Treatment of acute dystonia includes discontinuation of the offending agent and restoring the dopaminergic-cholinergic balance in the basal ganglia. Diphenhydramine and biperiden are the most common medications that are available in the emergency setting for the treatment of acute dystonia.

Discussion

Drug-induced EPSs are common in clinical scenarios. There are four commonly recognized EPSs, including parkinsonism, akathisia, acute dystonia, and tardive dyskinesia. 1 Among the EPSs, acute dystonia happens commonly in children and young adults. It begins shortly (usually within 48 hours) after the patient takes antipsychotic or anti-dopaminergic drugs. 2 Acute dystonia is characterized by involuntary contractions of muscles of the extremities, face, neck, abdomen, pelvis, or larynx, and the contraction could be in sustained or intermittent patterns that lead to abnormal postures or movements. Anticholinergic agents and benzodiazepines are commonly used to treat acute dystonia. Diphenhydramine is effective in reversing acute dystonia for its anticholinergic effect and central nervous system penetration. Biperiden is another effective anticholinergic medication with fast onset. Benzodiazepines may be considered second-line medication for patients who fail to respond to anticholinergic agents.

Our patient took anti-emetic medication (metoclopramide) for two days and was sent to our emergency department, which was mistaken for a seizure at first. His symptoms and medication history suggested acute dystonia, a typical presentation of drug-induced EPS. The patient was treated with biperiden. Two minutes after the injection, the dystonic posturing returned to normal.