Normal pressure hydrocephalus (NPH) is a rare condition that mainly occurs in older people and can lead to symptoms of dementia if not recognised and treated in the early stages. This page, written by our dementia specialist Admiral Nurses, explains what it is, the symptoms, causes, diagnosis and treatment.
What is NPH?
Our bodies naturally produce a clear, watery liquid called cerebrospinal fluid (CSF) that protects the brain and spinal cord, delivers nutrients and removes waste products. CSF is produced, circulated and stored in cavities within the brain called ventricles.
Sometimes, too much CSF builds up within the brain. This is known as ‘hydrocephalus’. It enlarges the ventricles and puts pressure on the brain, which can lead to problems with balance and thinking.
NPH is a form of hydrocephalus where, despite there being an abnormal build-up of CSF within the brain, measurements of pressure are normal. This is why it is called ‘normal pressure’ hydrocephalus.
What causes NPH?
NPH is relatively rare and is mainly diagnosed in older people. There are two main types of NPH:
- Idiopathic NPH has an unknown cause and is most common in people over the age of 60
- Secondary NPH occurs after a brain injury, for example a head injury, brain surgery, stroke, meningitis or subarachnoid haemorrhage (bleeding in the space around the brain)
Symptoms
There are three main symptoms that present in NPH:
- Walking difficulties: balance problems, shuffling and walking with the feet wider apart than usual
- Impaired thinking: memory problems, slowed thought processes and concentration problems
- Urinary incontinence: needing to pass urine urgently and/or frequently, and loss of bladder control
How is NPH diagnosed?
If someone is diagnosed with NPH, early treatment can help, so it is important to see a GP if you notice these possible symptoms. They may refer the person for a scan, and if NPH is suspected, they may also refer them to a neurologist. However, a diagnosis of NPH is sometimes delayed because the early symptoms are often attributed to something else, for example ageing, frailty or dementia.
A full holistic assessment should be completed to identify if there are any reasons for the changes that the person is experiencing. The assessment should establish when the symptoms started, what happens and what, if anything, relieves the symptoms.
The assessment should include a brain scan (MRI or CT scan). If the person has NPH, the scan will reveal enlarged ventricles in the brain with very little to no associated brain shrinkage.
The person may also have a lumbar puncture, where a small sample of CSF is taken from the lower spine using a needle.
Treatment
If NPH is identified and treated early, the symptoms may be reversible. However, if it is diagnosed late, it can lead to dementia due to the ongoing pressure in the brain caused by the build-up of CSF.
Treatment involves having a small tube, known as a ventriculoperitoneal shunt, inserted into the brain by a surgeon. This drains excess CSF from the brain into the abdomen. This is done under general anaesthetic and usually involves a short hospital stay of one to three days.
Regular follow-up is needed to ensure that the shunt is working successfully and to monitor the symptoms, but if it is still working after six months, the person may then only need an annual check-up. If there is a problem such as a blockage, the person’s medical team will try to fix this.
Not everyone with NPH will benefit from shunt surgery, and because there is a risk of complications such as under- or over-drainage, infection, bleeding or abdominal pain, tests will be done to assess whether the potential benefits outweigh the risks. For example, if the person has certain other physical health conditions or is frail, the procedure may be too risky.
If the person is not suitable for shunt surgery, other strategies can be put in place to help manage the symptoms of NPH, for example making adaptations to the home to reduce the risk of falls and supporting the person to manage incontinence.
How we can support you?
Dementia UK can support you if you have questions about preventing dementia or any other aspect of the condition.
‘Dementia: what next?’: free online sessions for people with dementia, families and friends, hosted by dementia specialist Admiral Nurses.
Admiral Nurse Dementia Helpline: call free on 0800 888 6678 (Monday-Friday 9am-9pm, Saturday and Sunday 9am-5pm, every day except 25th December) or email helpline@dementiauk.org.
Virtual clinic appointments: book a free phone or video call with an Admiral Nurse at a time to suit you.