What is hydrocephalus?

Hydrocephalus is when cerebrospinal fluid (CSF) accumulates in the brain.

Normally, CSF is made in the brain to cushion the brain, provide nutrients and remove toxins. It is removed from around the brain in a cycle. But CSF can build up if:

• the brain makes too much
• there is a blockage and it cannot drain properly
• it is not being absorbed into the bloodstream

Causes of hydrocephalus

If a child is born with hydrocephalus, it is called congenital hydrocephalus. This is usually caused by a problem in the CSF process when the baby’s brain is developing.

People can also get hydrocephalus as a child or as an adult after a head injury, after bleeding in the brain, after a brain tumour or after meningitis, which is an infection around the brain.

Another cause of hydrocephalus is spina bifida, a birth defect that affects the spine. Hydrocephalus can develop in children with spina bifida before or after they are born.

Symptoms of hydrocephalus

The most common symptoms of hydrocephalus are headache, nausea, vomiting and fits.

For babies, hydrocephalus can also cause:

• increased head size
• bulging or firm fontanelle, which is the soft spot on a baby’s head
• poor feeding
• drowsiness or sleepiness
• eye turning inwards
• seizures

For older children or adults, hydrocephalus can also cause:

• blurred or double vision
• problems concentrating
• loss of coordination
• confusion
• incontinence
• seizures

Sometimes hydrocephalus can put pressure on the optic nerve in the eye. This can cause strabismus (where the eyes aren’t straight), gaze palsies (the person can’t move their eyes together upwards) or nystagmus (a rapid abnormal movement in the eyes).

Diagnosis of hydrocephalus

If someone has symptoms of hydrocephalus, tests can be done to check for extra fluid in the brain. They include:

• ultrasound
• computerised tomography scan, or CT
• magnetic resonance imaging scan, or MRI
• lumbar puncture

Treatment of hydrocephalus

While often hydrocephalus can’t be cured, it can be controlled. Treatment aims to reduce pressure on the brain. The usual approach is surgery to place a fine tube called a shunt that helps drain the fluid.