Normal pressure hydrocephalus Dr Rob Hicks This condition, literally translated, means 'water on the brain' and can affect older people.

In this article

What is normal pressure hydrocephalus? Symptoms

Causes and risk factors Treatment and recovery

Hydrocephalus is best known as a condition that affects babies and children. In these cases it is usually associated with a dangerous increase in pressure within the skull.

Normal pressure hydrocephalus (NPH), however, occurs in people in their 60s and 70s, and is not linked to an increase pressure within the skull.

There are three symptoms common to everyone diagnosed with NPH: gait (walking) disturbance (including shuffly steps, freezing, and falls), urinary (and sometimes faecal) incontinence and dementia (memory and speech loss, abnormal behaviour, apathy, mood changes, difficulty with reasoning).

Some experts now believe that the gait disturbance means that many people are misdiagnosed as having Parkinson’s Disease, while the dementia is misdiagnosed as Alzheimer's. But correct diagnosis and treatment of NPH may reverse some of the symptoms.

NPH is an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain, with little or no increase in pressure within the system.

In most people, the cause is unknown; in others it can be secondary to head injury, subarachnoid haemorrhage or an infection such as meningitis. These conditions may leave scarring which interferes with the way that CSF drains from the brain.

Most people initially talk to their GP about symptoms, who should then consider referral to a neurologist or neurosurgeon for further investigations.

NPH cannot generally be cured, but it can be controlled, and symptoms sometimes improved, by surgical treatments, medicines to control symptoms, and practical support.

In some cases an operation may remove a blockage to the flow of CSF such as that caused by a brain tumour. But surgery usually involved placing a fine tube known as a shunt into the brain to drain out excess CSF and re-route it to another part of the body, usually the abdomen.

This leads to substantial relief of symptoms in some patients, but some will get worse again while others have no benefit at all. Its difficult to predict who will do well although patients whose symptoms improve after having some CSF removed by lumbar puncture are likely to benefit from surgery.

This article was last medically reviewed by Dr Trisha Macnair in March 2009.