What NPH is and the classic triad
Normal pressure hydrocephalus is characterised by the classic triad of gait disturbance, cognitive decline, and urinary incontinence, occurring in the setting of ventricular enlargement on brain imaging without significantly elevated cerebrospinal fluid pressure. NPH is important to recognise because it is one of the few potentially reversible causes of dementia � appropriate patients may experience significant improvement with ventriculoperitoneal shunt surgery.
Gait disturbance is typically the earliest and most prominent symptom, described as magnetic gait (feet stuck to the floor), shuffling with short steps, and balance impairment. Cognitive changes involve slowed thinking, apathy, and executive dysfunction rather than the memory loss typical of Alzheimer's disease. Urinary incontinence begins as urgency and frequency and progresses to incontinence. The classic triad may not be complete in all patients, which can delay diagnosis.
- Gait disturbance � magnetic gait, shuffling, balance problems
- Cognitive decline � slowed thinking, apathy, executive dysfunction
- Urinary incontinence � urgency, frequency, then incontinence
- Ventricular enlargement on MRI/CT without pressure elevation
Related: Dementia Doctor → · Dr. Jitendra Knowledge Hub → · ICHD-3 Topic →
Evaluation and shunt consideration
Evaluation begins with clinical assessment to identify the classic triad and exclude other causes. Brain MRI or CT shows ventricular enlargement disproportionate to cortical atrophy � the ventricular size is out of proportion to the degree of brain atrophy. Large-volume lumbar puncture (removal of 30-50 mL CSF) is a diagnostic and predictive test � temporary improvement in gait or cognition after tap predicts good response to shunt surgery.
Shunt surgery (ventriculoperitoneal shunt) is considered when clinical features, imaging, and lumbar tap response are consistent with NPH. The procedure diverts excess CSF from the ventricles to the peritoneal cavity, relieving pressure on brain tissue. Complications include shunt infection, over-drainage, and mechanical failure, requiring careful patient selection and surgical expertise. Dr. Jitendra Prasad Yadav (NMC 8029) provides NPH evaluation and shunt referral at Kathmandu Neurology Clinic, Durbar Marg, Opposite of Yak & Yeti Hotel.
| Test | Purpose | Positive Finding |
|---|---|---|
| MRI/CT brain | Ventricular enlargement | Ventricles large out of proportion to atrophy |
| Large-volume lumbar tap | Predict shunt response | Gait/cognitive improvement after CSF removal |
| Gait analysis | Document baseline | Magnetic gait, shuffling, short steps |
| Cognitive testing | Document impairment | Executive dysfunction, slowed thinking |