Hydrocephalus in children and adults: what signs, what tests and what treatments?

How does hydrocephalus develop?

Cerebrospinal fluid is produced continuously in the ventricles of the brain, flows around the brain and spinal cord, and is then reabsorbed. Hydrocephalus occurs when this flow is blocked or when reabsorption is insufficient. The fluid builds up, the ventricles enlarge and the pressure may rise.

The causes vary:

• a malformation present at birth, such as a narrowing of the channel linking two ventricles, or hydrocephalus associated with spina bifida;
• an infection, particularly meningitis or a neonatal infection, which can leave hydrocephalus as an after-effect;
• bleeding in the brain, especially in very premature babies;
• a tumour compressing the pathways along which the fluid flows;
• in older adults, a particular form known as normal pressure hydrocephalus.

What signs should raise concern?

In infants

An infant’s skull has not yet fused: the head can grow in size. Warning signs are head circumference growing too fast on the health record chart, a tense or bulging fontanelle, dilated scalp veins, eyes turned downwards, vomiting, irritability or, on the contrary, unusual drowsiness, and difficulty feeding.

In older children and adults

The skull can no longer expand: pressure rises more quickly. Headaches, often in the morning, vomiting, visual disturbances, drowsiness and difficulties at school or with concentration may appear. Worsening drowsiness or repeated vomiting is an emergency.

Normal pressure hydrocephalus in older adults

This form gradually combines walking difficulties, problems with memory or attention, and urinary leakage. These signs can be mistaken for other diseases of ageing; a specialist assessment makes it possible to tell them apart.

How is the diagnosis made?

In infants, ultrasound through the fontanelle shows the ventricles without radiation. CT and especially MRI clarify the cause, the location of any blockage and the condition of the brain. Regular measurement of head circumference and neurological examination complete the assessment. In adults suspected of normal pressure hydrocephalus, specific tests, such as assessing walking before and after removing some fluid, can help establish whether treatment is indicated.

What treatments may be offered?

Draining the cerebrospinal fluid

The most common treatment is to place a shunt: a thin tube carries fluid from the ventricles to another body cavity, usually the abdomen, where it is reabsorbed. A valve regulates the flow. This treatment is effective, but the shunt can become blocked, infected or unsuitable as the child grows; a new operation is then needed.

Endoscopic third ventriculostomy

In some forms, particularly when an obstruction blocks the flow, the neurosurgeon can endoscopically create a new route for the fluid, without leaving any device in the body. In some infants, this procedure may be combined with cauterising part of the structures that produce the fluid. The indication depends on the cause, the age and the anatomy.

Treating the cause

When a tumour is responsible, treating it may be enough to restore the flow of fluid. Hydrocephalus caused by an infection requires the infection to be treated first.

Living with a shunt

A person with a shunt, or their parents, must know the signs that may indicate a malfunction: headaches, vomiting, drowsiness, irritability, visual disturbances, the return of the initial signs, redness or discharge along the path of the shunt, fever. These signs require urgent medical attention. It is useful to carry information about the valve: type, date of insertion and setting if it is an adjustable valve, as some strong magnetic fields, such as MRI, can change the setting of certain valves.

Preventing some forms of hydrocephalus

Taking folic acid before and in early pregnancy reduces the risk of spina bifida, a malformation often associated with hydrocephalus. Preventing and promptly treating infections in newborns, and following up very premature babies, also help limit some forms.

Frequently asked questions