Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Viewpoint
  • Published:

Idiopathic normal pressure hydrocephalus: the benefits and problems of shunting

Nature Clinical Practice Neurology volume 5, pages 80–81 (2009)Cite this article

The syndrome of idiopathic normal pressure hydrocephalus (INPH) is characterized by ventriculomegaly in the absence of raised intracranial pressure and presents as the clinical triad of gait disturbance, urinary incontinence and cognitive impairment. Diversion of the cerebrospinal fluid (CSF) through implantation of a shunt is the mainstay of therapy for INPH. However, a number of difficulties face the medical practitioner in the selection of patients for shunt surgery and provision of optimum follow-up. We outline these issues and describe the methods by which we believe clinicians can ensure the best possible outcomes from shunting for INPH.

One of the first issues that confronts practitioners is the fact that diagnosing INPH is itself problematic—symptoms are often attributed to aging or to other conditions that mimic hydrocephalus, causing the diagnosis of INPH to be missed. To ensure the selection of those patients who are most likely to benefit from shunt placement, it is critical, therefore, that a sensitive and accurate method of selection is used.1 If shunt placement was offered solely on the basis of patient history, examination, and presence of ventriculomegaly on neuroimaging, only 46–61% of patients with possible or probable INPH would benefit from surgery. To improve these odds, practitioners have supplemented these investigations with additional selection criteria based on physiological testing (such as the determination of CSF outflow resistance) or functional testing (such as the CSF tap test and extended lumbar drainage [ELD]). ELD, whereby small amounts of CSF are drained daily over a period of 3 days via a spinal catheter, has been shown to have the highest sensitivity and specificity (60–100% and 50–100%, respectively).2 In fact, the additional quantifiable improvement in patient function during ELD denotes a much greater chance of surgical success than the mere presence of the clinical and radiological appearance of INPH. In a prospective study of 151 patients, preoperative use of ELD as a supplementary test had a 90% predictive value for good outcomes after shunt surgery for INPH.3 The test was most accurate in patients with predominant gait symptoms and less accurate with increasing number and severity of symptoms in the INPH triad. In a similar study, ELD predicted improvement when gait impairment was the primary symptom, and when the duration of symptoms was short.4 These data suggest that ELD can accurately select patients who will benefit from shunting, and this is currently the best supplementary test available.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

References

  1. Gallia GL et al. (2006) The diagnosis and treatment of idiopathic normal pressure hydrocephalus. Nat Clin Pract Neurol 2: 375–381

    Article  Google Scholar 

  2. Marmarou A et al. (2005) The value of supplemental prognostic tests for the preoperative assessment of idiopathic normal-pressure hydrocephalus. Neurosurgery 57: S17–S28

    PubMed  Google Scholar 

  3. Marmarou A et al. (2005) Diagnosis and management of idiopathic normal-pressure hydrocephalus: a prospective study in 151 patients. J Neurosurg 102: 987–997

    Article  Google Scholar 

  4. McGirt MJ et al. (2005) Diagnosis, treatment, and analysis of long-term outcomes in idiopathic normal-pressure hydrocephalus. Neurosurgery 57: 699–705

    Article  Google Scholar 

  5. Raftopoulos C et al. (1994) Cognitive recovery in idiopathic normal pressure hydrocephalus: a prospective study. Neurosurgery 35: 397–404

    Article  CAS  Google Scholar 

  6. Duinkerke A et al. (2004) Cognitive recovery in idiopathic normal pressure hydrocephalus after shunt. Cogn Behav Neurol 17: 179–184

    Article  Google Scholar 

  7. Williams MA et al. (2008) Objective assessment of gait in normal-pressure hydrocephalus. Am J Phys Med Rehabil 87: 39–45

    Article  Google Scholar 

  8. McQuarrie IG et al. (1984) Treatment of normal pressure hydrocephalus with low versus medium pressure cerebrospinal fluid shunts. Neurosurgery 15: 484–488

    Article  CAS  Google Scholar 

  9. Boon AJ et al. (1998) Dutch Normal-Pressure Hydrocephalus Study: randomized comparison of low- and medium-pressure shunts. J Neurosurg 88: 490–495

    Article  CAS  Google Scholar 

  10. Pujari S et al. (2008) Normal pressure hydrocephalus: long-term outcome after shunt surgery. J Neurol Neurosurg Psychiatry 79: 1282–1286

    Article  CAS  Google Scholar 

  11. Gangemi M et al. (2008) Endoscopic third ventriculostomy in idiopathic normal pressure hydrocephalus: an Italian multicenter study. Neurosurgery 63: 62–67

    Article  Google Scholar 

  12. Williams MA et al. (2007) Influence of shunt surgery on healthcare expenditures of elderly fee-for-service Medicare beneficiaries with hydrocephalus. J Neurosurg 107: 21–28

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. S Batra is a Research Assistant at Johns Hopkins School of Medicine, and D Rigamonti is Professor of Neurosurgery, Radiation Oncology and Molecular Sciences, Radiology, and Physical Medicine and Rehabilitation, at Johns Hopkins Hospital, Baltimore, MD, USA.,

    Sachin Batra & Daniele Rigamonti

Authors
  1. Sachin Batra
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Daniele Rigamonti
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Daniele Rigamonti.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Batra, S., Rigamonti, D. Idiopathic normal pressure hydrocephalus: the benefits and problems of shunting. Nat Rev Neurol 5, 80–81 (2009). https://doi.org/10.1038/ncpneuro1004

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ncpneuro1004

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing