Treatment of Normal Pressure Hydrocephalus in Elderly Patients
Ventriculoperitoneal shunt surgery is the definitive treatment for normal pressure hydrocephalus in elderly patients who demonstrate positive response to predictive testing, with properly selected patients having an 80-90% chance of symptom improvement. 1
Initial Diagnostic Confirmation and Patient Selection
Before proceeding to treatment, confirm the diagnosis using MRI without contrast to identify ventriculomegaly, callosal angle <90°, periventricular white matter changes, and the critical aqueductal flow void 1. The diagnosis requires ventricular enlargement not entirely attributable to cerebral atrophy, no macroscopic CSF flow obstruction, and clinical features of the classic triad 1.
Predictive Testing for Shunt Responsiveness
Perform large-volume lumbar puncture (tap test) or prolonged external lumbar drainage to identify patients likely to respond to shunt surgery 1. This testing is critical because:
- A positive tap test has high positive predictive value for therapeutic response 2
- Clinical improvement following CSF removal reliably identifies shunt responders 1
- Consider repeating the tap test 2-3 times on consecutive days if initial results are equivocal, as this improves predictive value 3
- A negative tap test does not exclude the possibility of treatment benefit 2
Elevated aqueductal CSF stroke volume measured by phase-contrast MRI also demonstrates high positive predictive value for shunt responsiveness 1, 4.
Definitive Surgical Treatment
Proceed with ventriculoperitoneal shunt placement in patients who demonstrate positive response to predictive testing 1. Key technical considerations include:
- Use adjustable valves with anti-gravity or anti-siphon devices to minimize complications including low-pressure headaches and subdural collections 5
- Expect gait and balance to improve more reliably than cognition and bladder symptoms 3
- All symptoms have potential for improvement with proper patient selection 1
- Serious complication rate is approximately 6% 1
Post-Shunt Management and Follow-Up
Close long-term neurological follow-up is mandatory, with evaluation of shunt function if clinical deterioration occurs 5. Approximately 45% of patients experience symptom recurrence at 1-year follow-up, requiring valve adjustment or system revision 5.
Monitoring Strategy
- Assess shunt function immediately if clinical deterioration occurs 5
- Regularly evaluate for neuropsychiatric symptoms using validated tools including NPI-Q, Geriatric Depression Scale, or Cornell Scale for Depression in Dementia 5
- Optimize management of comorbid conditions including pain, sensory impairments, and sleep disturbances that contribute to cognitive symptoms 5
Behavioral and Non-Pharmacological Management
Implement non-pharmacological behavioral interventions as first-line management for neuropsychiatric symptoms, including caregiver education, enhanced communication strategies, meaningful activities, and structured routines 5.
Caregiver Support
Assess caregiver burden regularly using structured scales such as the Zarit Burden Interview, as caregiver burden is a major determinant of hospitalization and nursing home placement 5. Provide caregiver education about dementia progression and brainstorm problem-solving approaches with caregivers to address specific behavioral issues 5.
Prognostic Factors
Early intervention with shorter symptom duration predicts better outcomes 5. The cardinal presenting symptom is typically the hypokinetic gait disorder where feet appear "glued to the floor" or "magnetic," occurring in approximately 70% of NPH patients 1. This gait disturbance often shows the most dramatic improvement following shunt placement 6, 7.
Important Caveats
In elderly populations, prognosis after 3 years may be less favorable despite initial improvement, often due to associated pathologies, particularly neurodegenerative diseases 3. This should be considered in decision-making regarding CSF shunt placement, though it does not preclude treatment in appropriately selected patients who demonstrate positive predictive testing 3.