A 72-year-old man presents with resting tremor, bradykinesia, and lead-pipe rigidity for 2 years. He has postural hypotension, rapid eye movement sleep behavior disorder (RBD), urinary incontinence, and his UPDRS motor score does NOT significantly improve with levodopa. The most likely diagnosis is:
- A Idiopathic Parkinson's disease
- B Dementia with Lewy bodies
- C Multiple system atrophy (MSA) ✓
- D Progressive supranuclear palsy (PSP)
Explanation
Multiple system atrophy (MSA) presents with parkinsonism plus autonomic failure (orthostatic hypotension, urinary dysfunction) and cerebellar features. Poor or absent levodopa response is a red flag against idiopathic PD. MSA-P (parkinsonian variant) mimics PD but lacks robust dopa-responsiveness. RBD is actually common in ALL alpha-synucleinopathies (PD, DLB, MSA). PSP characteristically features vertical supranuclear gaze palsy and backward falls, without prominent autonomic failure. DLB has prominent cognitive fluctuations and visual hallucinations. Severe autonomic dysfunction + parkinsonism + levodopa-poor response = MSA.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.