Restlessness, tremor and jaw stiffness in a 24-year-old woman given metoclopramide for vomiting in pregnancy

Mrs A, a 24-year-old primigravida at 12 weeks' gestation, presented to the emergency department with a two-day history of persistent vomiting and an inability to tolerate oral intake. She was diagnosed with hyperemesis gravidarum and admitted for intravenous fluid resuscitation and antiemetic therapy.

On admission (Day 1), she was started on:

• Ondansetron 4 mg orally twice daily.
• Metoclopramide 10 mg intravenously three times daily.

Her condition improved, and she tolerated clear fluids. On Day 3, approximately 30 minutes after receiving the second morning dose of metoclopramide, she developed a sudden onset of restlessness, an inability to sit still, a fine tremor of her hands, and stiffness of her jaw. She described a feeling of inner anxiety and an urge to move.

On examination, her heart rate was 110 beats per minute, blood pressure 120/70 mmHg, respiratory rate 18 per minute, and temperature 36.8°C. Neurological examination revealed cogwheel rigidity in the upper limbs, a fine postural tremor, and trismus. There were no focal neurological deficits, and withdrawal or foetal distress was not evident.

Investigations showed normal serum electrolytes, calcium, magnesium, glucose, and thyroid function tests. ECG showed a sinus tachycardia. Urinalysis was unremarkable.

Metoclopramide was stopped immediately. Ondansetron was continued. Over the next 24 hours, her symptoms gradually resolved completely, and she felt well. No rechallenge with metoclopramide was attempted.

An alternative explanation of anxiety was considered, but the objective findings of tremor and jaw stiffness, together with the normal investigations, made this unlikely. Ondansetron was also considered but is a less likely cause given its low propensity for extrapyramidal reactions at the administered dose.