Psych · Consultation-liaison psychiatry
Normal pressure hydrocephalus and reversible dementias
Also known as Idiopathic normal pressure hydrocephalus · iNPH · Hakim–Adams syndrome · Treatable dementia · Potentially reversible dementia · Secondary NPH
Exam-exhaustive fellowship topic on idiopathic and secondary normal pressure hydrocephalus (Hakim–Adams triad, Relkin criteria, DESH, CSF tap test, shunt evidence from SINPHONI/SINPHONI-2/Toma) and the broader reversible-dementia concept (Clarfield, Hejl, Weytingh) — neuropsychiatric phenotype, differentials, work-up, capacity, and CL counselling. FRANZCP-primary, globally tagged.
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Target exams
Red flags
- Magnetic gait with progressive ventriculomegaly and urinary urgency — do not dismiss as 'just Alzheimer disease' without considering NPH
- Acute fluctuating confusion — delirium pathway first; do not make a new NPH diagnosis in an unsettled delirious state
- Rapid cognitive decline over weeks — widen organic differential (mass lesion, SDH, infection, autoimmune, metabolic)
- Promising full dementia cure after a single B12 injection when long-standing neurodegenerative disease coexists
- Shunt counselling without discussing infection, overdrainage, subdural collections, and revision risk
- Missing depression, anticholinergic burden, hypothyroidism, or OSA as treatable co-contributors
- Unsafe falls, driving, or financial exploitation while 'awaiting memory clinic'
Meet the patient
A 78-year-old widow is referred to CL as "depression, failing to thrive." For a year her gait has narrowed into a shuffle, she has started rushing to the toilet and not always making it, and she no longer balances her own chequebook. Her MMSE is 24. Her CT shows ventricles that look too big for the sulci, and the geriatric team have asked whether "this is the treatable dementia."[1][3][17]
Two questions run this station, and they are the examiner's favourites: is this NPH, and is it shunt-responsive? — and behind them the one that catches everyone: of all the dementias you call "reversible," how many actually reverse?[2][13][17]
References24ShowHide
- [1]Adams RD, Fisher CM, Hakim S, et al. SYMPTOMATIC OCCULT HYDROCEPHALUS WITH NORMAL CEREBROSPINAL-FLUID PRESSURE. A TREATABLE SYNDROME N Engl J Med, 1965.PMID 14303656
- [2]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.PMID 5889177
- [3]Relkin N, Marmarou A, Klinge P, et al. Diagnosing idiopathic normal-pressure hydrocephalus Neurosurgery, 2005.PMID 16160425
- [4]Marmarou A, Bergsneider M, Relkin N, et al. Development of guidelines for idiopathic normal-pressure hydrocephalus: introduction Neurosurgery, 2005.PMID 16160424
- [5]Bergsneider M, Black PM, Klinge P, et al. Surgical management of idiopathic normal-pressure hydrocephalus Neurosurgery, 2005.PMID 16160427
- [6]Hashimoto M, Ishikawa M, Mori E, et al. Diagnosis of idiopathic normal pressure hydrocephalus is supported by MRI-based scheme: a prospective cohort study Cerebrospinal Fluid Res, 2010.PMID 21040519
- [7]Kazui H, Miyajima M, Mori E, et al. Lumboperitoneal shunt surgery for idiopathic normal pressure hydrocephalus (SINPHONI-2): an open-label randomised trial Lancet Neurol, 2015.PMID 25934242
- [8]Nakajima M, Yamada S, Miyajima M, et al. Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus (Third Edition): Endorsed by the Japanese Society of Normal Pressure Hydrocephalus Neurol Med Chir (Tokyo), 2021.PMID 33455998
- [9]Toma AK, Papadopoulos MC, Stapleton S, et al. Systematic review of the outcome of shunt surgery in idiopathic normal-pressure hydrocephalus Acta Neurochir (Wien), 2013.PMID 23975646
- [10]Williams MA, Malm J Diagnosis and Treatment of Idiopathic Normal Pressure Hydrocephalus Continuum (Minneap Minn), 2016.PMID 27042909
- [11]Williams MA, Relkin NR Diagnosis and management of idiopathic normal-pressure hydrocephalus Neurol Clin Pract, 2013.PMID 24175154
- [12]Carswell C Idiopathic normal pressure hydrocephalus: historical context and a contemporary guide Pract Neurol, 2023.PMID 36162853
- [13]Clarfield AM The decreasing prevalence of reversible dementias: an updated meta-analysis Arch Intern Med, 2003.PMID 14557220
- [14]Hejl A, Høgh P, Waldemar G Potentially reversible conditions in 1000 consecutive memory clinic patients J Neurol Neurosurg Psychiatry, 2002.PMID 12235305
- [15]Weytingh MD, Bossuyt PM, van Crevel H Reversible dementia: more than 10% or less than 1%? A quantitative review J Neurol, 1995.PMID 7595679
- [16]Hellström P, Klinge P, Tans J, et al. A new scale for assessment of severity and outcome in iNPH Acta Neurol Scand, 2012.PMID 22587624
- [17]Kito Y, Kazui H, Kubo Y, et al. Neuropsychiatric symptoms in patients with idiopathic normal pressure hydrocephalus Behav Neurol, 2009.PMID 19996513
- [18]Siraj S An overview of normal pressure hydrocephalus and its importance: how much do we really know? J Am Med Dir Assoc, 2011.PMID 21194654
- [19]Moore E, Mander A, Ames D, et al. Cognitive impairment and vitamin B12: a review Int Psychogeriatr, 2012.PMID 22221769
- [20]Malouf R, Areosa Sastre A Vitamin B12 for cognition Cochrane Database Syst Rev, 2003.PMID 12918012
- [21]Sachdev PS, Blacker D, Blazer DG, et al. Classifying neurocognitive disorders: the DSM-5 approach Nat Rev Neurol, 2014.PMID 25266297
- [22]Livingston G, Huntley J, Sommerlad A, et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission Lancet, 2020.PMID 32738937
- [23]Appelbaum PS, Grisso T Assessing patients' capacities to consent to treatment N Engl J Med, 1988.PMID 3200278
- [24]Nasreddine ZS, Phillips NA, Bédirian V, et al. The Montreal Cognitive Assessment, MoCA: a brief screening tool for mild cognitive impairment J Am Geriatr Soc, 2005.PMID 15817019