Hot Cross Buns

A 55 year old man is initially diagnosed with Parkinson's disease. He has bradykinesia, rigidity, postural instability, and an irregular jerky action tremor of the arms. Parkinson's was initially diagnosed by his primary care physician when he had multiple falls at home. Since then, however, he's developed extensor plantar responses, severe anterior flexion of the spine (camptocormia), anterocollis, and dysphagia. With these progressive changes, he is sent to you.

When you begin talking to the patient, you note hypophonic monotony. His wife says his voice has also undergone an increase in pitch and gained a quivering, strained element. She's also noticed a weird change in his sleep; he talks, shouts, and occasionally even strikes out into the air. When he awakes, he says he had a vivid, frightening dream. He also has a high-pitched inspiratory noise during his sleep; he is being worked up for obstructive sleep apnea. On review of systems, you find that he has symptomatic orthostatic hypotension, erectile dysfunction, and urinary dysfunction. He does not seem to exhibit any cognitive changes.

Here is a T2 weighted MRI:

Challenge: What's your diagnosis?

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