Normal Pressure Hydrocephalus

Normal Pressure Hydrocephalus

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Normal pressure hydrocephalus (NPH) is a clinical symptom complex caused by the build-up of cerebrospinal fluid. This condition is characterized by abnormal gait, urinary incontinence, and (potentially reversible) dementia. See the image below.

Patients with NPH present with a gradually progressive disorder. The classic triad consists of the following:

Abnormal gait: Earliest feature and most responsive to treatment; bradykinetic, broad-based, magnetic, and shuffling gait

Urinary incontinence: Urinary frequency, urgency, or frank incontinence

Dementia: Prominent memory loss and bradyphrenia; forgetfulness, decreased attention, inertia

See Clinical Presentation for more detail.

Laboratory testing

In general, laboratory testing is not helpful in the diagnosis of NPH. However, a levodopa challenge may be helpful to rule out idiopathic Parkinson disease; patients with NPH have no significant response to levodopa or dopamine agonists.

Imaging studies

Imaging studies are invaluable in the diagnosis of NPH. In most cases of new-onset neurologic symptoms, obtain an initial computed tomography scan of the brain. Although magnetic resonance imaging is more specific than CT scanning in NPH, a normal CT scan can exclude the diagnosis.


All patients with suspected NPH should undergo diagnostic CSF removal (either large volume lumbar puncture and/or external lumbar drainage), which has both diagnostic and prognostic value. Improvement in symptoms with large-volume drainage supports the diagnosis of NPH.

See Workup for more detail.


Surgical CSF shunting remains the main treatment modality for NPH. Prior to embarking upon surgical therapy, knowing which patients may benefit from surgery is necessary. Detailed testing is performed before and after CSF drainage (eg, baseline neuropsychological evaluation, timed walking test, large-volume lumbar puncture, external lumbar drainage, CSF infusion testing).

Ideal candidates for shunt surgery would show imaging evidence of ventriculomegaly, as indicated by a frontal horn ratio exceeding 0.50 on imaging studies, along with one or more of the following criteria:

Presence of a clearly identified etiology

Predominant gait difficulties with mild or absent cognitive impairment

Substantial improvement after CSF withdrawal (CSF tap test or lumbar drainage)

Normal-sized or occluded sylvian fissures and cortical sulci on CT scan or MRI

Absent or moderate white-matter lesions on MRI

An alternative technique to shunt surgery is endoscopic third ventriculostomy.


No definitive evidence exists that medication, including levodopa/carbidopa, can successfully treat NPH. Although levodopa/carbidopa has been reported to be of benefit in anecdotal reports, patients with NPH may represent misdiagnosed cases of parkinsonism. However, in patients who are poor candidates for shunt surgery, repeated lumbar punctures in combination with acetazolamide may be considered. [1]

See Treatment and Medication for more detail.

Normal pressure hydrocephalus (NPH) is a clinical symptom complex characterized by abnormal gait, urinary incontinence, and dementia. It is an important clinical diagnosis because it is a potentially reversible cause of dementia. First described by Hakim in 1965, NPH describes hydrocephalus in the absence of papilledema and with normal cerebrospinal fluid (CSF) opening pressure on lumbar puncture. [2]

NPH differs from other causes of adult hydrocephalus. An increased subarachnoid space volume does not accompany increased ventricular volume. Clinical symptoms result from distortion of the central portion of the corona radiata by the distended ventricles. This may also lead to interstitial edema of the white matter and impaired blood flow, as suggested in nuclear imaging studies. The periventricular white matter anatomically includes the sacral motor fibers that innervate the legs and the bladder, thus explaining the abnormal gait and incontinence. Compression of the brainstem structures (ie, pedunculopontine nucleus) could also be responsible for gait dysfunction, particularly the freezing of gait that has been well described. Dementia results from distortion of the periventricular limbic system.

The term normal pressure hydrocephalus was based on the finding that all 3 patients reported by Hakim and Adams showed low CSF pressures at lumbar puncture, namely 150, 180, and 160 mm H2 O. However, an isolated CSF pressure measurement by lumbar puncture clearly yields a poor estimation of the real intracranial pressure (ICP) in patients with NPH.

Hakim first described the mechanism by which a normal or high-normal CSF pressure exerts its effects. Using the equation, Force = Pressure X Area, increased CSF pressure over an enlarged ependymal surface applies considerably more force against the brain than the same pressure in normal-sized ventricles. Normal pressure hydrocephalus may begin with a transient high-pressure hydrocephalus with subsequent ventricular enlargement. With further enlargement of the ventricles, CSF pressure returns to normal; thus the term NPH, at least in view of the initial pathophysiologic events, is a misnomer. Intermittent intracranial hypertension has been noted in some patients.

Some authors prefer the term extraventricular obstructive hydrocephalus. They believe that the initial event is diminished CSF absorption at the arachnoid villi. This obstruction to CSF flow leads to transient high-pressure hydrocephalus with subsequent ventricular enlargement. As the ventricles enlarge, CSF pressure returns to normal.

See the list below:

A Norwegian study of a population of 220,000 inhabitants found a prevalence of probable idiopathic NPH of 21.9 per 100,000 population and an incidence of 5.5 per 100,000 population; the investigators suggested that those numbers be regarded as minimum estimates. [3]

A Japanese study found radiological and clinical features consistent with idiopathic NPH in 2.9% of community-dwelling elderly subjects. [4]

In another Japanese study, elderly individuals (age >65 y) underwent MRI and the prevalence of NPH was 1.4%. [5]

The prevalence of NPH may be as high as 14% in extended care facility patients. [6]

Race is not associated with the development of NPH.

Gender is not associated with the development of NPH.

NPH is predominantly a disease of the elderly, and thus with the aging of the population, its recognition is of increased importance. The Norwegian study mentioned above showed the incidence and prevalence of NPH increasing with age. [3]

Aimard G, Vighetto A, Gabet JY, Bret P, Henry E. [Acetazolamide: an alternative to shunting in normal pressure hydrocephalus? Preliminary results]. Rev Neurol (Paris). 1990. 146(6-7):437-9. [Medline].

Hakim S, Adams RD. The special clinical problem of symptomatic hydrocephalus with normal cerebrospinal fluid pressure. Observations on cerebrospinal fluid hydrodynamics. J Neurol Sci. 1965 Jul-Aug. 2(4):307-27. [Medline].

Brean A, Eide PK. Prevalence of probable idiopathic normal pressure hydrocephalus in a Norwegian population. Acta Neurol Scand. 2008 Jul. 118(1):48-53. [Medline].

Hiraoka K, Meguro K, Mori E. Prevalence of idiopathic normal-pressure hydrocephalus in the elderly population of a Japanese rural community. Neurol Med Chir (Tokyo). 2008 May. 48(5):197-99; discussion 199-200. [Medline].

Tanaka N, Yamaguchi S, Ishikawa H, Ishii H, Meguro K. Prevalence of possible idiopathic normal-pressure hydrocephalus in Japan: the Osaki-Tajiri project. Neuroepidemiology. 2009. 32(3):171-5. [Medline].

Marmarou A, Young HF, Aygok GA. Estimated incidence of normal pressure hydrocephalus and shunt outcome in patients residing in assisted-living and extended-care facilities. Neurosurg Focus. 2007 Apr 15. 22(4):E1. [Medline].

Sakakibara R, Uchiyama T, Kanda T, Uchida Y, Kishi M, Hattori T. [Urinary dysfunction in idiopathic normal pressure hydrocephalus]. Brain Nerve. 2008 Mar. 60(3):233-9. [Medline].

Bech-Azeddine R, Hogh P, Juhler M, Gjerris F, Waldemar G. Idiopathic normal-pressure hydrocephalus: clinical comorbidity correlated with cerebral biopsy findings and outcome of cerebrospinal fluid shunting. J Neurol Neurosurg Psychiatry. 2007 Feb. 78(2):157-61. [Medline].

Golomb J, Wisoff J, Miller DC, et al. Alzheimer’s disease comorbidity in normal pressure hydrocephalus: prevalence and shunt response. J Neurol Neurosurg Psychiatry. 2000 Jun. 68(6):778-81. [Medline].

Graff-Radford NR, Godersky JC. Symptomatic congenital hydrocephalus in the elderly simulating normal pressure hydrocephalus. Neurology. 1989 Dec. 39(12):1596-600. [Medline].

Sasaki M, Honda S, Yuasa T, Iwamura A, Shibata E, Ohba H. Narrow CSF space at high convexity and high midline areas in idiopathic normal pressure hydrocephalus detected by axial and coronal MRI. Neuroradiology. 2008 Feb. 50(2):117-22. [Medline].

Gyldensted C. Measurements of the normal ventricular system and hemispheric sulci of 100 adults with computed tomography. Neuroradiology. 1977 Dec 31. 14(4):183-92. [Medline].

Singer OC, Melber J, Hattingen E, Jurcoane A, Keil F, Neumann-Haefelin T, et al. MR volumetric changes after diagnostic CSF removal in normal pressure hydrocephalus. J Neurol. 2012 May 17. [Medline].

Williams MA, Razumovsky AY, Hanley DF. Comparison of Pcsf monitoring and controlled CSF drainage diagnose normal pressure hydrocephalus. Acta Neurochir Suppl. 1998. 71:328-30. [Medline].

Governale LS, Fein N, Logsdon J, Black PM. Techniques and complications of external lumbar drainage for normal pressure hydrocephalus. Neurosurgery. 2008 Oct. 63(4 Suppl 2):379-84; discussion 384. [Medline].

Marmarou A, Young HF, Aygok GA, et al. Diagnosis and management of idiopathic normal-pressure hydrocephalus: a prospective study in 151 patients. J Neurosurg. 2005 Jun. 102(6):987-97. [Medline].

Murai R, Hashiguchi F, Kusuyama A, et al. Percutaneous stenting for malignant biliary stenosis. Surg Endosc. 1991. 5(3):140-2. [Medline].

Walchenbach R, Geiger E, Thomeer RT, Vanneste JA. The value of temporary external lumbar CSF drainage in predicting the outcome of shunting on normal pressure hydrocephalus. J Neurol Neurosurg Psychiatry. 2002 Apr. 72(4):503-6. [Medline].

Burnett MG, Sonnad SS, Stein SC. Screening tests for normal-pressure hydrocephalus: sensitivity, specificity, and cost. J Neurosurg. 2006 Dec. 105(6):823-9. [Medline].

Stein SC, Burnett MG, Sonnad SS. Shunts in normal-pressure hydrocephalus: do we place too many or too few?. J Neurosurg. 2006 Dec. 105(6):815-22. [Medline].

Hebb AO, Cusimano MD. Idiopathic normal pressure hydrocephalus: a systematic review of diagnosis and outcome. Neurosurgery. 2001 Nov. 49(5):1166-84; discussion 1184-6. [Medline].

Vanneste J, Augustijn P, Davies GA, Dirven C, Tan WF. Normal-pressure hydrocephalus. Is cisternography still useful in selecting patients for a shunt?. Arch Neurol. 1992 Apr. 49(4):366-70. [Medline].

Rangel-Castilla L, Barber S, Zhang YJ. The role of endoscopic third ventriculostomy in the treatment of communicating hydrocephalus. World Neurosurg. 2012 Mar. 77(3-4):555-60. [Medline].

Vanneste J, Augustijn P, Dirven C, Tan WF, Goedhart ZD. Shunting normal-pressure hydrocephalus: do the benefits outweigh the risks? A multicenter study and literature review. Neurology. 1992 Jan. 42(1):54-9. [Medline].

Boon AJ, Tans JT, Delwel EJ, et al. Dutch Normal-Pressure Hydrocephalus Study: the role of cerebrovascular disease. J Neurosurg. 1999 Feb. 90(2):221-6. [Medline].

Hamilton R, Patel S, Lee EB, Jackson EM, Lopinto J, Arnold SE. Lack of shunt response in suspected idiopathic normal pressure hydrocephalus with Alzheimer disease pathology. Ann Neurol. 2010 Oct. 68(4):535-40. [Medline].

Pujari S, Kharkar S, Metellus P, Shuck J, Williams MA, Rigamonti D. Normal pressure hydrocephalus: long-term outcome after shunt surgery. J Neurol Neurosurg Psychiatry. 2008 Nov. 79(11):1282-6. [Medline].

Hertel F, Zuchner M, Decker C, Schill S, Bosniak I, Bettag M. The Miethke dual switch valve: experience in 169 adult patients with different kinds of hydrocephalus: an open field study. Minim Invasive Neurosurg. 2008 Jun. 51(3):147-53. [Medline].

Brooks M. CSF Protein a Diagnostic Marker for Idiopathic NPH? Medscape Medical News. July 05, 2013. Available at Accessed: July 16, 2013.

Nishida N, Nagata N, Toda H, Ishikawa M, Urade Y, Iwasaki K. L-PGDS could be a surrogate marker of frontal lobe dysfunction in idiopathic NPH [abstract 1014]. Available at Accessed: July 16, 2013.

Tisell M, Hellstrom P, Ahl-Borjesson G, Barrows G, Blomsterwall E, Tullberg M. Long-term outcome in 109 adult patients operated on for hydrocephalus. Br J Neurosurg. 2006 Aug. 20(4):214-21. [Medline].

Tsakanikas D, Relkin N. Normal pressure hydrocephalus. Semin Neurol. 2007 Feb. 27(1):58-65. [Medline].

Walter C, Hertel F, Naumann E, Morsdorf M. Alteration of cerebral perfusion in patients with idiopathic normal pressure hydrocephalus measured by 3D perfusion weighted magnetic resonance imaging. J Neurol. 2005 Dec. 252(12):1465-71. [Medline].

Wikkelso C, Andersson H, Blomstrand C, Lindqvist G, Svendsen P. Normal pressure hydrocephalus. Predictive value of the cerebrospinal fluid tap-test. Acta Neurol Scand. 1986 Jun. 73(6):566-73. [Medline].

Michael J Schneck, MD, MBA Vice Chair and Professor, Departments of Neurology and Neurosurgery, Loyola University, Chicago Stritch School of Medicine; Associate Director, Stroke Program, Director, Neurology Intensive Care Program, Medical Director, Neurosciences ICU, Loyola University Medical Center

Michael J Schneck, MD, MBA is a member of the following medical societies: American Academy of Neurology, American Society of Neuroimaging, Stroke Council of the American Heart Association, Neurocritical Care Society

Disclosure: Received honoraria from Boehringer-Ingelheim for speaking and teaching; Received honoraria from Sanofi/BMS for speaking and teaching; Received honoraria from Pfizer for speaking and teaching; Received honoraria from UCB Pharma for speaking and teaching; Received consulting fee from Talecris for other; Received grant/research funds from NMT Medical for independent contractor; Received grant/research funds from NIH for independent contractor; Received grant/research funds from Sanofi for independe.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Nestor Galvez-Jimenez, MD, MSc, MHA The Pauline M Braathen Endowed Chair in Neurology, Chairman, Department of Neurology, Program Director, Movement Disorders, Department of Neurology, Division of Medicine, Cleveland Clinic Florida

Nestor Galvez-Jimenez, MD, MSc, MHA is a member of the following medical societies: American Academy of Neurology, American College of Physicians, International Parkinson and Movement Disorder Society

Disclosure: Nothing to disclose.

Selim R Benbadis, MD Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, Tampa General Hospital, University of South Florida Morsani College of Medicine

Selim R Benbadis, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, American Medical Association

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Acorda, Livanova, Eisai, Greenwich, Lundbeck, Neuropace, Sunovion, Upsher-Smith.<br/>Serve(d) as a speaker or a member of a speakers bureau for: Livanova, Eisai, Greenwich, Lundbeck, Neuropace, Sunovion.<br/>Received research grant from: Acorda, Livanova, Greenwich, Lundbeck, Sepracor, Sunovion, UCB, Upsher-Smith.

Arif I Dalvi, MD Director, Movement Disorders Center, NorthShore University Health System; Clinical Associate Professor of Neurology, University of Chicago Pritzker Medical School

Arif I Dalvi, MD is a member of the following medical societies: International Parkinson and Movement Disorder Society, European Neurological Society

Disclosure: Nothing to disclose.

Ashvini P Premkumar, MD Associate Director, Movement Disorders Center, NorthShore University HealthSystem, Clinical Instructor of Neurology, University of Chicago Pritzker Medical School

Ashvini P Premkumar, MD is a member of the following medical societies: American Academy of Neurology, International Parkinson and Movement Disorder Society

Disclosure: Nothing to disclose.

Normal Pressure Hydrocephalus

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