A 72-year-old man presents with the classic triad of gait apraxia, urinary incontinence, and dementia. MRI shows enlarged ventricles with normal sulci and no evidence of CSF outflow obstruction. Lumbar puncture opening pressure is normal. A large-volume lumbar tap transiently improves gait. The pathological basis involves:

• A Impaired CSF absorption by arachnoid granulations ✓
• B Obstruction of the cerebral aqueduct
• C Overproduction of CSF by choroid plexus papilloma
• D Amyloid deposition in the meninges

Explanation

This describes normal pressure hydrocephalus (NPH), characterized by the Hakim triad (gait apraxia, dementia, urinary incontinence). The pathophysiology involves impaired CSF absorption by arachnoid granulations, often idiopathic or secondary to prior subarachnoid hemorrhage or meningitis. Ventriculoperitoneal shunting can be therapeutic. Option B describes obstructive (non-communicating) hydrocephalus. Option C is rare. Option D is not a recognized cause.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.