A 22-year-old woman is brought to the emergency department for bizarre behavior over the past week. Her parents state that she has been "talking nonsense" nonstop, laughing for no reason, and has not slept for several days. During triage, the patient attempted to hit a staff member, resulting in administration of haloperidol. While awaiting further evaluation, the parents alert the nurse that the patient is starting to "make weird faces" while sticking out her tongue. Medical history is noncontributory, and the patient takes no medications. Urine drug screen is positive for cannabis and opiates. Which of the following is the most likely explanation for this patient's motor symptoms?
Common antipsychotic side effects | |
First-generation antipsychotics (FGAs) | High-potency (eg, haloperidol)
Low-potency (eg, chlorpromazine)
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Second-generation antipsychotics (SGAs) |
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This patient is likely experiencing an acute dystonic reaction in response to administration of haloperidol, a high-potency, first-generation antipsychotic. Acute dystonic reactions are a type of extrapyramidal symptom (EPS) thought to result from D2 antagonism in the nigrostriatal pathway. The condition develops abruptly within hours to days after receiving antipsychotic medication and is characterized by sudden involuntary contraction of a major muscle group (eg, this patient's tongue protrusion and facial grimacing). Other examples include torticollis (neck muscle contraction), oculogyric crisis (forced, sustained elevation of the eyes in an upward position), opisthotonus (arching of the back with the head thrown backward), and, rarely, laryngospasm.
Treatment of dystonic reactions consists of medications with anticholinergic properties (eg, diphenhydramine, benztropine), which alter cholinergic signaling in the striatum to decrease spontaneous movement. In addition to acute dystonia, other types of antipsychotic-induced EPS include akathisia (inner restlessness) and drug-induced parkinsonism (tremor, rigidity, bradykinesia, masked facies).
(Choice A) Catatonia is a motor disturbance seen in severe psychiatric or medical illness characterized by inability to move normally and resulting in either marked reduction in movements (eg, immobility, stupor) or marked agitation (stereotypy, hyperkinetic limb movements). The sudden onset of a spasm in a specific muscle group is more consistent with a dystonic reaction.
(Choice B) Conversion disorder (functional neurologic symptom disorder) is characterized by neurologic symptoms (eg, weakness, abnormal movements, nonepileptic seizures) that are inconsistent with known neurologic disease. It would not be diagnosed in a patient whose abnormal movements are readily explained by a medication reaction.
(Choice D) Symptoms of opioid withdrawal include gastrointestinal distress, lacrimation, rhinorrhea, myalgias/arthralgias, and yawning. These symptoms are not present in this patient and opioid withdrawal would not explain her tongue protrusion.
(Choice E) Patients with psychotic agitation may exhibit unusual movements and postures. However, the abrupt onset of tongue protrusion following administration of haloperidol is more likely explained as an acute dystonic reaction.
Educational objective:
Acute dystonic reaction is characterized by sudden, involuntary contraction of a major muscle group. It is a type of extrapyramidal symptom and a common adverse effect of antipsychotic medications, particularly high-potency, first-generation antipsychotics such as haloperidol.