What is the best management for normal pressure hydrocephalus (NPH)?

Management of Normal Pressure Hydrocephalus

Ventriculoperitoneal (VP) shunt placement is the definitive treatment for normal pressure hydrocephalus, achieving sustained clinical improvement for 5-7 years in appropriately selected patients. 1

Diagnostic Confirmation

Before proceeding with treatment, confirm the diagnosis with:

• MRI with contrast to evaluate for ventriculomegaly (specifically looking for Evans index >0.3 and enlarged temporal horns) and exclude other causes such as neurodegenerative disorders, which coexist in 75% of NPH cases requiring treatment 1, 2
• Predictive testing is essential since clinical and imaging findings alone are insufficient in most cases 2, 3

Prognostic Testing for Surgical Candidacy

The CSF tap test or extended lumbar drainage is recommended to predict shunt responsiveness, as these temporarily simulate the effect of definitive shunting 3:

• Single lumbar puncture (CSF tap test) has low sensitivity and cannot exclude patients from surgery 3
• Repeated CSF tap test (RTT) or continuous lumbar external drainage (LED) for 3-5 days provides the most reliable prediction of surgical benefit 3
• Standardized assessment of gait (Timed Up & Go, Tinetti Gait and Balance Assessment), balance (Berg Balance Scale), and cognition (Mini Mental Status Exam, Trail Making Test Part B) before and after temporary CSF diversion identifies patients likely to benefit, with 89.6% reporting improvement at 6 weeks 4
• The Tinetti score showing mean increase of >4 points after lumbar drain strongly predicts shunt success 4

Surgical Treatment Options

Primary Recommendation: VP Shunt

VP shunt placement remains the gold standard, with 70-90% of treated patients showing clinical improvement 2:

• Relief from symptoms is most prominent within the first 6 months and largely maintained long-term 5
• Median optimal opening pressure: 120 mmH2O for women, 140 mmH2O for men using programmable valves 5
• Gait disturbance responds best, followed by cognitive symptoms, then urinary incontinence 2, 3

Alternative: Endoscopic Third Ventriculostomy (ETV)

ETV has emerged as an alternative with lower long-term complication rates but higher early failure rates 6, 1:

• When adjusted for patient age and etiology, ETV shows higher failure rates in the first 3 months but lower failure rates after 3 months compared to shunts 6
• ETV is preferred when suitable anatomy exists, particularly in cases with aqueductal stenosis 1
• Both CSF shunts and ETV demonstrate equivalent overall outcomes in many clinical scenarios (Level II evidence) 6

Critical Management Pitfalls

Do not use serial lumbar punctures as definitive treatment (Level I evidence) - they are diagnostic tools only, not therapeutic interventions 6:

• Routine serial LPs do not reduce the need for shunt placement or prevent hydrocephalus progression 7

Complications and Monitoring

Infection Risk

• 11% of initial shunt placements develop infection within 24 months 1
• Management requires complete shunt removal with systemic antibiotics 7, 1

Other Complications

• Subdural fluid collections occur in 18% of patients postoperatively 4
• Other complications (seizure, intracerebral hemorrhage, stroke) occur in approximately 6% 4

Long-Term Outcomes

Approximately 45% of patients report symptom recurrence at 1 year despite initial improvement 1, 4:

• This necessitates ongoing monitoring and potential valve adjustments 5
• Clinical improvement is independent of radiological changes (Evans index and callosal angle), so prioritize clinical symptoms over imaging when adjusting valve settings 5
• Comorbidities, particularly diabetes mellitus and prior stroke, significantly influence surgical outcomes and should factor into prognostic discussions 5

Treatment Algorithm

1. Confirm diagnosis with MRI showing ventriculomegaly and exclude mimics 1, 2
2. Perform extended lumbar drainage (3-5 days preferred) with standardized gait, balance, and cognitive testing before and after 4, 3
3. If positive response (Tinetti score increase >4 points or meeting minimal clinically important differences on validated tests), proceed to VP shunt 4
4. Consider ETV if aqueductal stenosis present or patient anatomy favorable 1
5. Set initial valve pressure at 120 mmH2O (women) or 140 mmH2O (men) 5
6. Monitor closely in first 6 months for maximal improvement window 5
7. Adjust valve settings based on clinical symptoms, not imaging changes 5

The untreated spontaneous course of NPH leads to nursing care dependence in the vast majority of patients, making early treatment imperative when diagnosis is confirmed 2.