Treatment of Mild Normal Pressure Hydrocephalus
Ventriculoperitoneal shunt surgery is the definitive treatment for mild NPH and should be pursued early, as 70-90% of patients experience clinical improvement and delayed treatment leads to irreversible decline. 1, 2, 3
Diagnostic Confirmation Before Treatment
Before proceeding to surgery, confirm the diagnosis through:
MRI head without IV contrast as the preferred imaging modality to identify the complete constellation of NPH findings including ventriculomegaly, narrowed posterior callosal angle (<90°), effaced sulci along high convexities with widened Sylvian fissures (DESH pattern), periventricular white matter changes, and cerebral aqueduct flow void 1
Semi-invasive testing when diagnosis remains uncertain after imaging, using either:
Critical pitfall: Do not rely on cisternography alone to make surgical decisions—evidence is insufficient to proceed with or deny shunting based solely on DTPA cisternography findings, even when it shows characteristic CSF flow abnormalities 1
Surgical Intervention
Proceed with ventriculoperitoneal shunt placement using:
Adjustable valves with anti-gravity or anti-siphon devices to reduce the risk of low-pressure headaches and overdrainage complications 1
Neuronavigation for optimal shunt placement to reduce complications 1
Early intervention is crucial—shorter duration of symptoms predicts better outcomes, and approximately 75% of patients improve after shunt surgery regardless of shunt type or location 1, 3, 5
Alternative approach: Endoscopic third ventriculostomy may be considered in centers with neuroendoscopic experience if aqueductal stenosis is present, though it typically results in persistent ventriculomegaly 1, 3
Patient Selection Considerations for Mild NPH
Age matters significantly:
- Patients younger than 75 years have substantially better outcomes (64% improvement) compared to those older than 75 years (only 11% improvement at 5-year follow-up) 5
- However, age alone should not exclude patients from surgery if they are otherwise appropriate candidates 1
Comorbidity assessment:
- Three-quarters of NPH patients requiring treatment have another neurodegenerative disorder, complicating diagnosis 2
- High comorbidity burden and declining general health reduce long-term benefit 5
- Activities of daily living (Barthel index) should be assessed—higher baseline function predicts better outcomes 5
Medical Management (Not Recommended)
Acetazolamide is not an effective treatment for NPH and should not be used as an alternative to surgery 3
Post-Surgical Management
Implement close long-term neurological follow-up:
- Evaluate shunt function if deterioration occurs 1
- Adjust programmable valve settings based on symptoms and radiographic findings 3
- Anticipate that approximately 45% of patients experience symptom recurrence at 1 year, requiring valve adjustment or system revision 1
Expected outcomes at 6 months post-surgery:
- 83% improve in gait 5
- 65% improve in reaction time 5
- 46% improve in memory 5
- 96% report subjective improvement 5
Long-term outcomes at 5 years:
- Approximately 40% maintain improvement in gait and reaction time 5
- Cognitive improvements are less durable (fewer than 10% maintain improvement) 5
- 56% report subjective improvement compared to preoperative status 5
Critical Decision Point
The spontaneous course of untreated NPH ends in nursing care dependence for the vast majority of patients, and approximately 80% of cases remain unrecognized and untreated 2, 6. Given that modern shunt surgery improves outcomes in 70-90% of patients with acceptable complication rates, the risk/benefit analysis favors early surgical intervention for confirmed mild NPH rather than observation 2, 3.
Do not delay treatment waiting for symptoms to worsen—early intervention produces superior outcomes, and the window for reversibility narrows as the disease progresses 1, 2.