What Is Hydrocephalus

What Causes Hydrocephalus?

Hydrocephalus that is congenital (i.e. present at birth) is thought to be caused by a complex interaction of genetic and environmental factors. Acqueductal stenosis, an obstruction of the cerebral aqueduct (drainage pathways), is the most common cause of congenital hydrocephalus.

Acquired hydrocephalus (i.e. after birth) may result from spina bifida, intraventricular hemorrhage, meningitis, head trauma, tumours and cysts.

Normal Pressure Hydrocephalus (NPH) has, in most cases, an unknown cause. NPH can be caused as the result of a head injury, cranial surgery, subarachnoid haemorrhage, meningitis, tumor or cysts as well as subdural haematomas, bleeding during surgery, and other infections.

In many cases, there is no medical history to explain the development of NPH and its symptoms, making it difficult to diagnose and research.

How is Hydrocephalus Treated?

Most forms of hydrocephalus require treatment. The usual treatment is to insert a shunting device. It is important to note that this does not "cure" the hydrocephalus. Shunting controls the pressures by draining excess CSF, thus preventing the condition becoming worse. Symptoms caused by raised pressure usually improve but other problems of brain damage can remain.

What is a Shunt?

A shunt is simply a drain that diverts the accumulated CSF from the obstructed pathways and generally returns it into the abdomen. It is inserted surgically and is fully enclosed inside the body.

Hydrocephalus is an abnormal accumulation of Cerebro-Spinal Fluid, or CSF, within cavities called ventricles inside the brain.

CSF is produced in the ventricles, circulates through the ventricular system and is absorbed into the bloodstream.

CSF is in constant circulation and has many important functions. It surrounds the brain and spinal cord and acts as a protective cushion against injury. CSF contains nutrients and proteins that are needed for the nourishment and normal function of the brain. It also carries waste products away from surrounding tissues.

Hydrocephalus occurs when there is an imbalance between the amount of CSF that is produced and the rate at which it is absorbed.

As the CSF builds up, it causes the ventricles to enlarge and the pressure inside the head to increase.

Two Common Types of Hydrocephalus.

1. Congenital Hydrocephalus

is present at birth and is thought to be caused by a complex interaction of genetic and environmental factors.

Aqueductal stenosis, an obstruction of the cerebral aqueduct, is the most frequent cause of congenital hydrocephalus.

2. Normal Pressure Hydrocephalus (NPH)

Occurs after birth and is generally of an unknown cause. NPH can also develop as a result of a head injury, cranial surgery, subarachnoid haemorrhage, tumour or cysts, as well as subdural haematomas, bleeding during surgery, meningitis and other brain infections. All of these conditions can cause inflammation that affects the CSF pathways, impeding CSF flow.

Hydrocephalus affects about 1 in every 500 children born.

How is Hydrocephalus Treated?

To date there has been no known way to prevent or cure hydrocephalus. Once you have hydrocephalus, it is for life.

The most common way of treating hydrocephalus is by way of shunting. A shunt is a small pump connected to the ventricular system of the brain and then via a flexible tube diverts the Cerebrospinal fluid into another part of the body, usually the abdominal cavity or a chamber of the heart, where it can be absorbed. A pump (or valve) maintains the CSF at normal pressure within the ventricles.

Another way of treating the hydrocephalus is by way of a Third ventriculostomy. The neurosurgeon punctures a small hole(s) through the floor of the third ventricle so that the CSF can flow from the third ventricle into the fourth ventricle of the brain.

This procedure is restricted to about 25% of patients who need surgical intervention.

Some hydrocephalus sufferers do not need shunting or may have it delayed.

Many patients need more than one shunt in their lifetime.

Third ventriculostomies may also not be permanent.

How does Hydrocephalus affect the person?

Since the introduction of shunting in the 1950s, the outcome for most children (and adults) with hydrocephalus is much brighter.

Some children with hydrocephalus will have less than normal intelligence, whilst others go to university. There may also be physical disabilities, poor co-ordination and a variety of other medical problems.

Shunt malfunctions (and third ventriculostomy failure) and infections, developmental delays, learning disabilities and visual problems are not uncommon.

Hydrocephalus, once there, will not go away and families need to be continually aware and alert to the need of ongoing care and appropriate intervention.