Normal Pressure Hydrocephalus (NPH)

Neurology

Overview

Definition

A form of hydrocephalus characterized by the clinical triad of gait disturbance, cognitive decline, and urinary incontinence, with ventriculomegaly and normal CSF pressure on lumbar puncture.

Epidemiology

Primarily affects elderly individuals over 60 years old. Underdiagnosed cause of reversible dementia.

Etiology & Risk Factors

  • Impaired resorption of cerebrospinal fluid (CSF) by arachnoid granulations, leading to transient pressure elevation and ventricular dilation

Clinical Symptoms

  • Gait disturbance: Broad-based, magnetic gait ('feet glued to the floor')
  • Dementia: Psychomotor slowing, apathy, forgetfulness
  • Urinary urgency and incontinence
  • Classic mnemonic: 'Wet, wobbly, and wacky'

Clinical Approach

Diagnosis

  • Brain CT or MRI showing ventriculomegaly out of proportion to sulcal atrophy
  • Lumbar tap test (large-volume CSF removal showing transient improvement in gait)

Management

  • Ventricular shunt placement (ventriculoperitoneal shunt) for selected patients

Complications

  • Shunt occlusion or infection
  • Subdural hematoma (from over-drainage)
  • Falls and physical trauma