Normal pressure hydrocephalus: how often does the diagnosis hold water?

Area of Science:

• Neurology
• Neurosurgery
• Epidemiology

Background:

• Normal pressure hydrocephalus (NPH) is a neurological condition characterized by gait disturbance, cognitive impairment, and urinary incontinence.
• Shunt placement is a common treatment for NPH, but its long-term efficacy and complication rates require further investigation.

Purpose of the Study:

• To determine the incidence of clinically suspected NPH in a community.
• To assess the rate of shunting procedures for NPH.
• To evaluate the short- and long-term outcomes of shunting in NPH patients.

Main Methods:

• Retrospective review of medical records for Olmsted County, Minnesota residents from 1995-2003.
• Identification of patients undergoing invasive diagnostic procedures for suspected NPH.
• Assessment of early and long-term outcomes for patients who received shunts.

Main Results:

• The incidence of NPH was 1.19/100,000/year, with a sustained improvement rate of 0.36/100,000/year.
• While 75% experienced initial gait improvement, only 33% showed sustained improvement at 3 years.
• Complications occurred in 33% of patients, and alternative diagnoses were identified in 5 of 12 patients.

Conclusions:

• NPH is a rare condition, and shunt placement provides only modest long-term benefits, particularly for gait.
• Cognitive and urinary symptoms showed limited long-term improvement after shunting.
• Baseline postural instability is a predictor of poor outcomes, necessitating careful consideration of risks versus benefits.