Movement Disorders USMLE Step 1 Practice Question
A 72-year-old man with a 15-year history of Parkinson disease presents to the clinic with progressive cognitive decline over the past 18 months, recurrent visual hallucinations of small animals and insects, and orthostatic hypotension. Vital signs show BP 98/62 mmHg supine, 82/48 mmHg standing, with heart rate 102 bpm. He reports no recent falls or syncope. Current medications include levodopa 750 mg daily and carbidopa. On examination, he demonstrates cogwheel rigidity, bradykinesia, and postural instability, but notably absent resting tremor. MRI of the brain shows preserved substantia nigra without atrophy. Which of the following is the most likely diagnosis?
Answer choices
- AParkinson disease with early dementia
- BLewy body dementiaCorrect answer
- CMultiple system atrophy
- DProgressive supranuclear palsy
- ECorticobasal degeneration
- FVascular parkinsonism
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