Case Presentation: The patient, a 52-year-old female with a history of migraine, presented with persistent right-sided migraine without aura. She developed akathisia shortly after receiving Prochlorperazine. Her symptoms improved with Diphenhydramine, and she was discharged home.She returned to the ED the same evening due to the progression of her symptoms. Neurological examination showed binocular diplopia, a left-sided facial droop, weakness (0/5) in the left upper and lower extremities, bilateral hypertonia and hyperreflexia, along with choreiform movements on the right. CT scan of the head was unremarkable. Due to the unusual presentation, she was started on steroids, and empiric antimicrobials, and received additional Diphenhydramine with no improvement. Given the persistence of her symptoms, Benztropine was administered, resulting in a marked improvement in her hyperkinetic symptoms. However, her left-sided paralysis persisted. Later, an MRI of the head was performed, revealing a cryptogenic right-sided medullary stroke. During her hospital stay, her stroke symptoms steadily improved, and she was ultimately discharged to an inpatient rehabilitation facility.
Discussion: Medication-induced movement disorders are clinical syndromes associated with basal ganglia and extrapyramidal dysfunction, manifesting as either excess or paucity of both voluntary and involuntary movements. The most common triggers are anti-dopaminergic agents, particularly first-generation antipsychotics and anti-emetics such as Metoclopramide and Prochlorperazine. Less common causes include anticonvulsants, antidepressants, antimalarials and stroke.Ischemic stroke can cause both hypokinetic and hyperkinetic movement disorders. In the early post-stroke stage, most patients experience paralysis. Dystonic reactions are usually the sequelae of chronic stroke. However, acute dystonia can be the presenting feature of acute ischemic stroke involving the motor cortex, cerebellum and basal ganglia.The treatment for a drug-induced movement disorder involves discontinuing the offending agent and administration of anticholinergic medications, such as Diphenhydramine and Benztropine. For persistent symptoms, intravenous Benzodiazepines are the preferred choice. Post-stroke dystonia tends to respond poorly to medications, but some trials have shown limited efficacy of Baclofen and local botulinum toxin injections.Our case presented a unique diagnostic challenge as the patient experienced an acute paralytic right medullary stroke and a drug-induced hyperkinetic movement disorder simultaneously, resulting in an unusual initial presentation. The stroke by itself would not fully explain the dystonia on the ipsilateral side as there was no injury to the basal ganglia, cerebellum, or mid-brain structures immediately involved in dampening hyperkinetic motor activity. She was administered anticholinergic agents, with the resolution of hyperkinetic symptoms; however, paralysis persisted. This suggests that her drug-induced movement disorder was bilateral, with the concurrent stroke masking the symptoms on one side. It is also important to note that she had prior exposure to Prochlorperazine with no reported side effects.
Conclusions: Antiemetics can cause potentially life-threatening movement disorders. They are usually bilaterally and either hyper or hypokinetic. Unusual presentation with a combination of symptoms or unilaterality should prompt additional neurological evaluation.