MKSAP: 24-year-old woman with painful muscle spasms

Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 24-year-old woman is evaluated for a 3-week history of painful muscle spasms and twisting movements in the neck and trunk. She says that her neck feels as if it is being pulled backward. She also reports general restlessness and an inability to keep still. Her medical history is notable for asthma, type 1 diabetes mellitus, and gastroparesis with reflux. The patient has no family history of neuropsychiatric disorders or liver disease. Medications are albuterol, insulin, omeprazole, and metoclopramide.

On physical examination, vital signs are normal. When the patient is seated, her neck pulls backward and her chin elevates; mild grimacing movements also are noted. On standing and walking, her trunk arches backward, sometimes with her arms pulling forward.

Which of the following is the most likely diagnosis?

A: Huntington disease
B: Juvenile Parkinson disease
C: Tardive dystonia
D: Wilson disease

MKSAP Answer and Critique

The correct answer is C: Tardive dystonia.

This patient has developed tardive dystonia involving her neck and trunk that is most likely caused by the metoclopramide she is taking. The associated facial grimacing (a classic finding in tardive dyskinesia) and restlessness (akathisia) make the diagnosis of tardive dystonia certain because this constellation of symptoms does not occur in any other context. Tardive dystonia is a forceful, sometimes painful sustained contraction of muscles leading to twisted postures that must be distinguished from tardive dyskinesia, which consists of flowing, patterned choreic movements of the face. Both are caused by exposure to dopamine type 2 (D2) receptor antagonists, but the difference in the appearance of the movements has an important bearing on the treatment and prognosis. Tardive dystonia is more disabling than tardive dyskinesia and also harder to treat. The therapeutic approach includes a gradual discontinuation of the offending agent, treatment with anticholinergic or dopamine receptor-depleting agents, and the judicious use of botulinum toxin injections.

Huntington disease is a familial disorder causing generalized chorea, dementia, and behavioral changes. This patient does not exhibit these symptoms.

Juvenile Parkinson disease can cause parkinsonism in a child or young adult. This patient does not exhibit symptoms of parkinsonism.

Wilson disease causes copper accumulation in the basal ganglia and liver and may present as progressive parkinsonism or dystonia. Symptom onset is usually in childhood or teenage years. This patient does not have parkinsonism, Kayser-Fleischer rings, or a family history of neuropsychiatric or hepatic disease, which renders the diagnosis of Wilson disease unlikely.

Key Point

  • Tardive dystonia, a disorder whose classic findings include facial grimacing and akathisia, can be induced by dopamine receptor antagonists, such as metoclopramide and antipsychotic drugs.

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