Normal Pressure Hydrocephalus - Draft

Overview

Normal pressure hydrocephalus (NPH) happens when too much fluid builds up in a person’s brain without increasing pressure in their brain tissue. People who have NPH are usually aged over 60. (1)

The importance of this diagnosis lies in the fact that it is a potentially reversible cause of dementia, accounting for up to 6% of dementias (2).

Symptoms that should raise suspicion about NPH include:

• Cognitive decline -  usually progresses more quickly than other causes of dementia.
• Gait abnormality - shuffling or 'magnetic' gait
• Urinary incontinence 

Who to Refer

The decision to refer will depend on symptoms suggestive of NPH and/or imaging. See below for further guidance provided by the local hydrocephalus service at NBT.

Symptoms

Normal Pressure Hydrocephalus is a clinical diagnosis which cannot be diagnosed based on radiology alone, thus it remains provisional until confirmed by neurosurgical review and diagnostic testing. The condition is not life threatening, but rather one that affects quality of life, including mobility, cognition and urinary function. 

Imaging

CT scan of the brain should be requested via ICE in all patients with suspected NPH. Please state clearly your concerns (including details of the patient's symptoms and signs) and that you wish to exclude NPH as a cause. 

Imaging may be ambiguous (3) but it is often diagnostic. However, there is not necessarily a good correlation with the imaging findings and clinical severity.

If imaging is suggestive of NPH then they should be referred as detailed in the Referral section below.

What to do before referral

The following information should be collated and included in a referral:

Gait - Describe any specific gait symptoms e.g. wide-based, shuffling and duration of these. Please include walking aid requirements.

Falls - Describe history of falls. Please include detail of mechanism, frequency, impact and injuries sustained.

Neurological impairment - Details of any other history of neurological impairment. E.g. previous CVA, tremor, or other neurodegenerative diagnosis. Please note Sodium valproate (Epilim) can mimic the symptoms of NPH, please consider alternative treatment or wean off as appropriate.

Cognitive function - Describe cognitive function, impact on ADLs and duration of impairment. Include any objective test scores (AMT, MoCA, ACE etc.).

It is possible for other comorbid dementia to occur alongside normal pressure hydrocephalus. If there any significant cognitive concerns which override gait disturbance, please consider referral to local memory services for assessment. However, please note that memory services will usually not accept referrals until any neurosurgical interventions have been completed or are not considered appropriate and there is a comorbid neurodegenerative disease.

Urinary symptoms - Presence and duration of urinary symptoms: Frequency, Urgency, Nocturia, Recurrent UTI, Other please comment (e.g. BPH, prostate Ca, prolapse).

Headaches - Describe any history of headaches

Social History - Include level of care, smoking/alcohol history and Rockwood frailty score

Radiology - Include details of radiology report, including location of scanning hospital and date.

Pre- op assessment - information to assess fitness for surgery is also very helpful to include in a referral - please see Pre-operative assessment page.

Referral

Referral to Neurosurgery - consider

Patients with clinical suspicion of NPH and supporting imaging findings should be referred to neurosurgery (for consideration of VP shunt) via eRS (Neurosurgery -Adult Hydrocephalus - RAS)

Patients must be fit enough/willing to undergo surgical treatment. Patients will undergo full pre-operative anaesthetic assessment if recommended for surgery. However, if prior optimisation of their chronic conditions is not achieved, this will result in a delay in treatment for elective surgery. In this regard, please ensure to optimise:

• Diabetes to achieve an Hba1C < 69mm/mol
• Lung and cardiac conditions including specialist review if required. The need for lung function tests, echocardiogram and rhythm studies will cause delay to treatment. Syncope is not a symptom of iNPH and should be investigated for alternative cause.
• Skin is intact, chronic open wounds are a barrier to surgery due to infection risk.

If there is doubt about appropriateness of surgical intervention then consider requesting neurology advice and guidance. (is this appropriate)

Referral to Dementia Service

Patients should only be referred to the Dementia Wellbeing Service if no neurosurgical or neurology-led intervention is appropriate and there is a comorbid neurodegenerative disease.

Resources

(1) Alzheimers Society - Normal Pressure Hydrocephalus

(2) Patient.uk - Normal Pressure Hydrocephalus

(3) Normal pressure hydrocephalus | Radiology Reference Article | Radiopaedia.org

Efforts are made to ensure the accuracy and agreement of these guidelines, including any content uploaded, referred to or linked to from the system. However, BNSSG ICB cannot guarantee this. This guidance does not override the individual responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or guardian or carer, in accordance with the mental capacity act, and informed by the summary of product characteristics of any drugs they are considering. Practitioners are required to perform their duties in accordance with the law and their regulators and nothing in this guidance should be interpreted in a way that would be inconsistent with compliance with those duties.

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