Normal Pressure Hydrocephalus
This constellation of gait disturbance, memory loss, and urinary incontinence in an elderly patient describes Normal Pressure Hydrocephalus (NPH). 1, 2
Classic Clinical Triad
NPH presents with three cardinal features that typically develop in a specific temporal sequence:
- Gait disturbance occurs first and earliest in the disease course, characterized by a hypokinetic pattern where the feet appear "glued to the floor" or "magnetic," present in approximately 70% of NPH patients 3, 4
- Cognitive impairment develops later, manifesting as frontal lobe symptoms including psychomotor slowing, deficits in attention, working memory, verbal fluency, and executive function—not primarily memory loss initially 1
- Urinary incontinence includes urgency, frequency, and nocturia, representing the autonomic dysfunction component of the syndrome 4, 5
Why Not the Other Options
Alzheimer disease presents primarily with progressive memory loss and cognitive decline without the early prominent gait disturbance or urinary symptoms characteristic of NPH 6.
Lewy body dementia is characterized by visual hallucinations, Parkinsonian symptoms (resting tremor, bradykinesia, rigidity), and fluctuating cognition—not the specific triad seen here 6.
Wernicke syndrome presents acutely with confusion, ataxia, and ophthalmoplegia in the context of thiamine deficiency, typically related to alcohol use disorder or malnutrition—not a chronic progressive syndrome over months 1.
Critical Diagnostic Features
- Patients present late in the disease course due to the slow, gradual onset of symptoms over months to years 2
- NPH affects approximately 3.7% of patients over 65 years of age and represents one of the few potentially reversible causes of dementia 2, 4
- Comorbidity is common: approximately 20-57% of NPH patients also have Alzheimer's disease or other neurodegenerative conditions, which can complicate the clinical picture 1, 2
Recommended Diagnostic Approach
MRI brain without IV contrast is the preferred initial imaging modality, demonstrating ventriculomegaly, narrowed posterior callosal angle (<90°), effaced sulci, widened sylvian fissures, periventricular white matter changes, and cerebral aqueduct flow void 6, 1, 2, 3.
CT head without IV contrast is an acceptable alternative when MRI is contraindicated or unavailable, though it provides less detailed soft-tissue characterization 6, 2.
Treatment Implications
CSF diversion through shunting is the definitive treatment, with properly selected patients having an 80-90% chance of responding to surgery 3. Clinical improvement following large-volume lumbar puncture or prolonged external lumbar drainage reliably predicts shunt responsiveness 3. All three symptoms—gait, cognition, and urinary function—can potentially improve with treatment, though gait improvement is most consistent 3, 7, 5.