What is the prognosis of normal pressure hydrocephalus (NPH)?

Updated: Oct 19, 2018
  • Author: Michael J Schneck, MD, MBA; Chief Editor: Selim R Benbadis, MD  more...
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Answer

The overall prognosis of NPH remains poor both due to a lack of improvement in some patients following surgery as well as a significant complication rate. In a study by Vanneste et al, one of the more comprehensive studies described above, marked improvement was noted in only 21% of patients following shunt surgery. Complication rate was approximately 28% with death or severe residual morbidity in 7% of patients, further emphasizing the importance of careful patient selection. [24] Concomitant cerebrovascular disease is a recognized negative prognostic factor. [25]

In a small prospective study, Hamilton et al measured the impact of cortical Alzheimer disease pathology on shunt responsiveness in 37 individuals treated for idiopathic NPH. Clinical measures, including neuropsychometrics and gait, were correlated with amyloid β (Aβ) plaques, neuritic plaques, and neurofibrillary tangles observed in cortical biopsies obtained during shunt insertion. Patients with no tau and Aβ pathology and mild tau and Aβ pathology improved on the neuropsychometric and gait evaluations. In contrast, patients with moderate-to-severe pathology did not show improvement on any study measure. However, the relatively small numbers in the study, presence of contradictory studies, and absence of a widely accepted biomarker for Alzheimer disease make it difficult to use this finding while evaluating patients with NPH. [26]

In patients who develop recurrent symptoms after initial improvement, shunt malfunction should be suspected and an evaluation for mechanical failure should be pursued. In some of these cases, catheter migration may have occurred, which is a correctable cause of shunt malfunction. In one case series, shunt revision was required in more than half of treated patients over a 6-year period, with improvement in most of these patients. [27]


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