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Normal-Pressure Hydrocephalus (NPH)


General Information


  • NPH is a progressive but treatable disorder that can develop in adulthood and is characterized by enlarged cerebral ventricles (ventriculomegaly) but normal or only slightly elevated cerebrospinal fluid pressure1, 2, 3
  • NPH presents with ≥ 1 symptom of the triad of gait disturbance, dementia, and urinary incontinence1, 2, 3

Also Called

  • although the following terms are sometimes used, it is recommended that they be avoided, as they are based on proposed pathophysiological mechanisms3
    • communicating hydrocephalus1, 2, 3
    • malresorptive hydrocephalus3


  • idiopathic NPH (also referred to as primary NPH or iNPH)
    • accounts for about 50% of NPH cases and is the most common form of hydrocephalus in adults1, 2
    • affects adults ≥ 40 years old and most common in elderly adults1, 3
  • secondary NPH (sNPH)1, 2, 3
    • caused by another medical condition, such as, subarachnoid hemorrhage, meningitis, intracerebral hemorrhage, brain tumor, or traumatic brain injury
    • may affect persons of any age
  • classification into 1 of these 2 types may not be clinically significant since the clinical syndrome of NPH is the same for both iNPH and sNPH1
    • pathogenesis remains unclear
    • diagnosis based on clinical history, neurological examination, and brain imaging
    • treatment usually cerebrospinal fluid shunting


General references used

  1. Oliveira LM, Nitrini R, Román GC. Normal-pressure hydrocephalus: A critical review. Dement Neuropsychol. 2019 Apr;13(2):133-143OpenInNewfull-textOpenInNew
  2. Williams MA, Malm J. Diagnosis and Treatment of Idiopathic Normal Pressure Hydrocephalus. Continuum (Minneap Minn). 2016 Apr;22(2 Dementia):579-99OpenInNewfull-textOpenInNew
  3. Kiefer M, Unterberg A. The differential diagnosis and treatment of normal-pressure hydrocephalus. Dtsch Arztebl Int. 2012 Jan;109(1-2):15-25OpenInNewfull-textOpenInNew

Recommendation grading systems used

  • American Academy of Neurology (AAN) grading system for recommendations
    • levels of recommendations
      • Level A - established as effective, ineffective, or harmful (requires ≥ 2 consistent Class I studies)
      • Level B - probably effective, ineffective, or harmful (requires ≥ 1 Class I study or ≥ 2 consistent Class II studies)
      • Level C - possibly effective, ineffective, or harmful (requires ≥ 1 Class II study or 2 consistent Class III studies)
      • Level U - data inadequate or conflicting; given current knowledge, treatment is unproven (studies not meeting criteria for Class I-III)
    • classes of studies
      • Class I - randomized controlled trial (RCT) with masked outcome assessment in representative population, equivalent baseline characteristics or appropriate statistical adjustment for differences, and adequate accounting for dropouts and crossovers with numbers sufficiently low to have minimal potential for bias
      • Class II - prospective matched group cohort study with masked outcome assessment in representative population
      • Class III - all other controlled trials including well-defined natural history controls or patients serving as own controls in representative population, where outcome assessment is independently assessed or derived from objective outcome measurement
      • Class IV - uncontrolled study, case series, case report, or expert opinion
    • Reference - AAN practice guideline on idiopathic normal-pressure hydrocephalus: response to shunting and predictors response (26644048Neurology 2015 Dec 8;85(23):2063OpenInNewfull-textOpenInNew), correction can be found in Neurology 2016 Feb 23;86(8):793OpenInNewfull-textOpenInNew

Synthesized Recommendation Grading System for DynaMed

  • DynaMed systematically monitors clinical evidence to continuously provide a synthesis of the most valid relevant evidence to support clinical decision-making (see 7-Step Evidence-Based MethodologyOpenInNew).
  • Guideline recommendations summarized in the body of a DynaMed topic are provided with the recommendation grading system used in the original guideline(s), and allow DynaMed users to quickly see where guidelines agree and where guidelines differ from each other and from the current evidence.
  • In DynaMed (DM), we synthesize the current evidence, current guidelines from leading authorities, and clinical expertise to provide recommendations to support clinical decision-making in the Overview & Recommendations section.
  • We use the Grading of Recommendations Assessment, Development and Evaluation (GRADE)OpenInNew to classify synthesized recommendations as Strong or Weak.
    • Strong recommendations are used when, based on the available evidence, clinicians (without conflicts of interest) consistently have a high degree of confidence that the desirable consequences (health benefits, decreased costs and burdens) outweigh the undesirable consequences (harms, costs, burdens).
    • Weak recommendations are used when, based on the available evidence, clinicians believe that desirable and undesirable consequences are finely balanced, or appreciable uncertainty exists about the magnitude of expected consequences (benefits and harms). Weak recommendations are used when clinicians disagree in judgments of relative benefit and harm, or have limited confidence in their judgments. Weak recommendations are also used when the range of patient values and preferences suggests that informed patients are likely to make different choices.
  • DynaMed (DM) synthesized recommendations (in the Overview & Recommendations section) are determined with a systematic methodology:
    • Recommendations are initially drafted by clinical editors (including ≥ 1 with methodological expertise and ≥ 1 with content domain expertise) aware of the best current evidence for benefits and harms, and the recommendations from guidelines.
    • Recommendations are phrased to match the strength of recommendation. Strong recommendations use "should do" phrasing, or phrasing implying an expectation to perform the recommended action for most patients. Weak recommendations use "consider" or "suggested" phrasing.
    • Recommendations are explicitly labeled as Strong recommendations or Weak recommendations when a qualified group has explicitly deliberated on making such a recommendation. Group deliberation may occur during guideline development. When group deliberation occurs through DynaMed-initiated groups:
      • Clinical questions will be formulated using the PICO (Population, Intervention, Comparison, Outcome) framework for all outcomes of interest specific to the recommendation to be developed.
      • Systematic searches will be conducted for any clinical questions where systematic searches were not already completed through DynaMed content development.
      • Evidence will be summarized for recommendation panel review including for each outcome, the relative importance of the outcome, the estimated effects comparing intervention and comparison, the sample size, and the overall quality rating for the body of evidence.
      • Recommendation panel members will be selected to include at least 3 members that together have sufficient clinical expertise for the subject(s) pertinent to the recommendation, methodological expertise for the evidence being considered, and experience with guideline development.
      • All recommendation panel members must disclose any potential conflicts of interest (professional, intellectual, and financial), and will not be included for the specific panel if a significant conflict exists for the recommendation in question.
      • Panel members will make Strong recommendations if and only if there is consistent agreement in a high confidence in the likelihood that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. Panel members will make Weak recommendations if there is limited confidence (or inconsistent assessment or dissenting opinions) that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. No recommendation will be made if there is insufficient confidence to make a recommendation.
      • All steps in this process (including evidence summaries which were shared with the panel, and identification of panel members) will be transparent and accessible in support of the recommendation.
    • Recommendations are verified by ≥ 1 editor with methodological expertise, not involved in recommendation drafting or development, with explicit confirmation that Strong recommendations are adequately supported.
    • Recommendations are published only after consensus is established with agreement in phrasing and strength of recommendation by all editors.
    • If consensus cannot be reached then the recommendation can be published with a notation of "dissenting commentary" and the dissenting commentary is included in the topic details.
    • If recommendations are questioned during peer review or post publication by a qualified individual, or reevaluation is warranted based on new information detected through systematic literature surveillance, the recommendation is subject to additional internal review.

DynaMed Editorial Process

Special acknowledgements

  • DynaMed topics are written and edited through the collaborative efforts of the above individuals. Deputy Editors, Section Editors, and Topic Editors are active in clinical or academic medical practice. Recommendations Editors are actively involved in development and/or evaluation of guidelines.
  • Editorial Team role definitions
    Topic Editors define the scope and focus of each topic by formulating a set of clinical questions and suggesting important guidelines, clinical trials, and other data to be addressed within each topic. Topic Editors also serve as consultants for the internal DynaMed Editorial Team during the writing and editing process, and review the final topic drafts prior to publication.
    Section Editors have similar responsibilities to Topic Editors but have a broader role that includes the review of multiple topics, oversight of Topic Editors, and systematic surveillance of the medical literature.
    Recommendations Editors provide explicit review of DynaMed Overview and Recommendations sections to ensure that all recommendations are sound, supported, and evidence-based. This process is described in "Synthesized Recommendation Grading."
    Deputy Editors are employees of DynaMed and oversee DynaMed internal publishing groups. Each is responsible for all content published within that group, including supervising topic development at all stages of the writing and editing process, final review of all topics prior to publication, and direction of an internal team.

How to cite

National Library of Medicine, or "Vancouver style" (International Committee of Medical Journal Editors):

  • DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T113928, Normal-Pressure Hydrocephalus (NPH); [updated 2018 Nov 30, cited place cited date here]. Available from Registration and login required.
  • KeyboardArrowRight

    Overview and Recommendations

    • Background

    • Evaluation

    • Management

  • Related Summaries

  • KeyboardArrowRight

    General Information

    • Description

    • Also Called

    • Types

  • KeyboardArrowRight


    • Who is most affected

    • Incidence/Prevalence

    • Risk factors

    • Associated conditions

  • KeyboardArrowRight

    Etiology and Pathogenesis

    • Causes

    • Pathogenesis

  • KeyboardArrowRight

    History and Physical

    • KeyboardArrowRight


      • Chief concern (CC)

      • History of present illness (HPI)

    • KeyboardArrowRight


      • Neuro

  • KeyboardArrowRight


    • Making the diagnosis

    • Differential diagnosis

    • Testing overview

    • Imaging studies

    • Cerebrospinal fluid (CSF) analysis

    • Other diagnostic testing

  • KeyboardArrowRight


    • Management overview

    • Medications

    • KeyboardArrowRight

      Surgery and procedures

      • KeyboardArrowRight

        Cerebrospinal fluid (CSF) shunting

        • Surgical techniques

        • Recommendations

        • Efficacy of CSF shunting

        • CSF shunt valves

        • CSF shunt complications

      • Serial lumbar punctures

      • Endoscopic third ventriculoscopy

    • Follow-up

  • KeyboardArrowRight

    Complications and Prognosis

    • Complications

    • Prognosis

  • Prevention and Screening

  • KeyboardArrowRight

    Guidelines and Resources

    • KeyboardArrowRight


      • United States Guidelines

      • United Kingdom Guidelines

      • Canadian Guidelines

      • European Guidelines

      • Asian Guidelines

    • Review Articles

    • MEDLINE Search

  • Patient Information

  • KeyboardArrowRight

    ICD Codes

    • ICD-10 codes

  • KeyboardArrowRight


    • General references used

    • Recommendation grading systems used

    • Synthesized Recommendation Grading System for DynaMed

    • DynaMed Editorial Process

    • Special acknowledgements

    • How to cite

Topic Editor
Gregory S. Day MD, MSc, FRCPC

Assistant Professor, Department of Neurology, Washington University in St. Louis; Missouri, United States; Clinician, The Rehabilitation Institute of St. Louis, BJC Healthcare and HealthSouth, Washington University School of Medicine; Missouri, United States; Clinician, Memory Diagnostic Center, Department of Neurology, Barnes Jewish Hospital; Missouri, United States; Clinical Director, The Anti-NMDA Receptor Encephalitis Foundation, Inc; Missouri, United States

Conflicts of Interest

Dr. Day declares relevant financial relationships with ANI Pharmaceuticals (Stock Shareholder), Eli Lilly (Sub PI), and Avid Radiopharmaceuticals (Grant/Research Support).

Recommendations Editor
Zbys Fedorowicz MSc, DPH, BDS, LDSRCS

Director of Bahrain Branch of the United Kingdom Cochrane Center, The Cochrane Collaboration; Awali, Bahrain

Conflicts of Interest

Dr. Fedorowicz declares no relevant financial conflicts of interest.

Deputy Editor
Alexander Rae-Grant MD, FRCPC, FAAN

Deputy Editor Neurology, DynaMed Plus; Massachusetts, United States; Neurologist, Cleveland Clinic; Ohio, United States

Conflicts of Interest

Dr. Rae-Grant declares no relevant financial conflicts of interest.

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