Normal pressure hydrocephalus (NPH) is an excessive build-up of fluid in the cavities or ventricles of the brain. Under normal conditions cerebrospinal fluid (CSF) circulates through the brain, its ventricles and the spinal cord acting as a protective cushion and provider of nutrients. NPH results when the flow of CSF is blocked in some way. NPH occurs most often in people aged over 60. The word Ԩydrocephalusՠis derived from the Greek words for water (Ԩydroթ and head (ԣephalusթ.
For most patients the cause of NPH cannot be determined. In some cases, history of previous brain injury or surgery can result in hydrocephalus. Examples are brain haemorrhage, aneurysm, trauma, tumors or cysts, infections or subdural haematomas. In other cases the imbalance in the production or absorption of CSF causes the hydrocephalus.
The three main symptoms are gait (walking) disturbance, dementia and urinary incontinence. Diagnosis of NPH is often difficult due to the symptoms being similar to other disorders. In many cases the NPH is thought to be mild dementia, Alzheimer's, Parkinson's or simply old age factors. Many cases go completely unrecognised and are never treated.
GPs should consider referring patients with these three symptoms to a neurologist or a neurosurgeon. The most common diagnostic tools are neuro-imaging devices, such as computerised tomography (CT) or magnetic resonance imaging (MRI), and a careful clinical assessment usually involving lumbar puncture.
Treatment is by an operation whereby a fine tube (called a shunt) is inserted inside one of the spaces of the brain so as to drain excess CSF and divert it to another part of the body where it is reabsorbed into the bloodstreams involve an operation.
