Movement Disorders USMLE Step 1 Practice Question
A 71-year-old woman with Parkinson disease treated with levodopa for 8 years presents with repetitive involuntary writhing and choreiform movements beginning 30 minutes after each dose. Vital signs: BP 138/82, HR 92, RR 16, Temp 37°C, SpO2 98%. Brain MRI shows no structural abnormalities. Her bradykinesia improves with medication, but tremor persists. She denies hallucinations. Which of the following best explains these new involuntary movements?
Answer choices
- AProgression to Huntington disease
- BAcute dystonic reaction from dopamine antagonism
- CEssential tremor unmasked by beta-blocker withdrawal
- DLevodopa-induced dyskinesia from pulsatile dopaminergic stimulationCorrect answer
- ECerebellar degeneration from alcohol use
- FTardive dyskinesia from chronic dopamine receptor blockade
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