A 70-year-old man develops a gait disturbance described by his family as 'walking as if his feet are glued to the floor', urinary urgency with incontinence, and slowing of mental processing over six months. CT shows ventricular enlargement out of proportion to sulcal atrophy. Lumbar puncture removes 30 mL of CSF with transient improvement in gait. What is the most likely diagnosis?
- A Alzheimer's disease
- B Vascular parkinsonism
- C Normal pressure hydrocephalus ✓
- D Progressive supranuclear palsy
Correct answer: C. Normal pressure hydrocephalus
Explanation
The classic triad of normal pressure hydrocephalus is gait apraxia (magnetic gait), urinary incontinence, and cognitive slowing, classically remembered as wet, wobbly, and wacky. Ventriculomegaly disproportionate to cortical atrophy and improvement of gait after large-volume lumbar tap confirm the diagnosis and predict benefit from ventriculoperitoneal shunting. PSP gives vertical gaze palsy, and vascular dementia gives stepwise decline with focal signs, neither of which is present here.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.