Hydrocephalus

When extra fluid builds up around the brain

Important. This is general educational information. Your child's situation is unique. Always talk to your child's treating doctor for advice that fits your child specifically.

If you have been told that your child has hydrocephalus, this page sets out what that means in plain language - what is happening inside the brain, how doctors look for it, what the treatment involves, and what to expect afterwards. The information here is general, your child's neurosurgeon will discuss what applies specifically to your child.

What is hydrocephalus?

The brain is surrounded by a clear, water-like liquid known as cerebrospinal fluid (CSF). The fluid is produced inside the brain, flows through small spaces called ventricles, and is then drained away and reabsorbed by the body. The CSF cushions the brain and helps to keep it healthy.

Hydrocephalus develops when this fluid is unable to drain away the way it should. It accumulates inside the ventricles of the brain and they become larger than they should be. The extra fluid then puts pressure on the brain, and that pressure is the cause of the problems your child may be experiencing.

Hydrocephalus is not a single disease but rather a condition with several possible causes. Some children are born with it. Others develop it later in life, for example after a premature birth with bleeding inside the brain, after a brain infection, after a head injury, or because of a brain tumor that obstructs the fluid pathway. The cause matters, it has a direct influence on how the hydrocephalus is treated.

Signs you might notice

The signs of hydrocephalus depend on the child's age, because the skull of an infant is still soft and growing while in an older child it is fixed.

In babies

  • Head growth that is faster than expected (the medical team will measure the head circumference at every visit)
  • A bulging or tense anterior fontanelle (the soft spot on top of the head)
  • Scalp veins that look more prominent than before
  • Eyes that drift downwards (the "sunsetting sign")
  • Unusual irritability, sleepiness, or feeding difficulty
  • Vomiting, often with no clear cause
  • Falling behind on developmental milestones

In older children

  • Morning headaches, particularly those that improve as the day progresses
  • Vomiting in the morning, occasionally without preceding nausea
  • Becoming more sleepy or harder to rouse than usual
  • Difficulty looking upwards, or eyes that do not move together
  • Decline at school, or loss of skills the child had previously mastered
  • Difficulty walking or new changes in balance

How is it diagnosed?

In babies whose fontanelle is still open, the doctors can often look at what is happening inside the brain using an ultrasound through the soft spot. The scan is painless and uses no radiation.

In older children, the test of choice is the MRI. The MRI uses a strong magnet (with no radiation) to take detailed pictures of the brain and the fluid spaces. Your child will need to lie still throughout the scan, younger children may require light sedation to achieve this.

A CT-scan is sometimes used instead, particularly in an emergency setting because it is fast. CT uses a small dose of X-ray radiation.

Your child's neurosurgeon will look at the scan together with the clinical symptoms to decide which type of hydrocephalus is present and what the next step should be.

How is it treated?

Hydrocephalus is treated by giving the trapped fluid a new way out. There are two main options. The choice between them depends on the age of the child, the underlying cause of the hydrocephalus, and the anatomy of the brain, and your child's neurosurgeon will discuss which is the right option for your child.

Ventriculo-peritoneal shunt (VP shunt)

A small tube placed inside the brain and connected to a valve, the system drains the excess fluid into the abdomen where the body absorbs it. The whole apparatus sits beneath the skin and is not visible from outside. The shunt is reliable and works for almost all causes of hydrocephalus. The downside is that it is a piece of equipment that can develop problems over time, most children with a shunt will need at least one repair (revision) during their lifetime, often within the first one to two years.

Endoscopic third ventriculostomy (ETV)

Instead of placing a tube, the neurosurgeon uses a small camera (an endoscope) to make a tiny opening in the floor of one of the brain's fluid spaces, allowing the fluid to drain naturally through the body's own channels. No equipment is left inside. The ETV works best for certain types of hydrocephalus and at certain ages, your child's neurosurgeon will explain whether your child is a suitable candidate. When the ETV is successful it works for life. When it is not, a shunt is the backup.

In some young infants, the neurosurgeon may combine the ETV with an additional step called choroid plexus cauterisation (CPC) to improve the chances of success. The neurosurgeon will discuss this if it applies to your child.

What can we expect?

The operation usually takes one to two hours. Your child will remain in hospital for several days afterwards while the team confirms that the system is working as it should. Most children go home with no restrictions on normal day-to-day activities, although the team will discuss activities that may need particular caution, such as contact sport.

When a shunt is in place, your child will need follow-up appointments at regular intervals, generally for life. The good news is that most children with a well-managed shunt grow up to live full lives - they go to school, work, and do everything other children do.

Because hydrocephalus has many possible causes, the long-term outlook depends far more on what caused the hydrocephalus than on the shunt or the ETV themselves. A child in whom hydrocephalus is the only problem will usually do well. A child whose hydrocephalus has come from a serious brain injury or a brain tumor will need additional care directed at that underlying cause.

And importantly, no family is going through this on their own. Paediatric neurosurgery teams, family doctors, school nurses, and patient organisations all work together to support children with hydrocephalus and their families.

Questions you might ask your child's doctor

  • What type of hydrocephalus does my child have, and what is the underlying cause?
  • Are you recommending a shunt, an ETV, or something else? What is the reasoning?
  • If my child is having a shunt, which kind of shunt and which valve, and what does that mean for follow-up?
  • What are the signs of a shunt problem that we should watch for at home?
  • How long will my child be in hospital, and what should we bring with us?
  • What activities are safe once my child is home? Sports, swimming, flying?
  • What is the follow-up schedule and who do we contact between appointments?
  • Are there other specialists my child will need to see, eye doctor, developmental paediatrician, neurologist?
  • What does the long-term outlook look like for a child like ours?

When to call your child's doctor right away

After treatment for hydrocephalus, particularly with a shunt in place, certain signs can mean that there is a problem with the shunt or with raised pressure in the brain. Do not wait, contact the neurosurgery team (or go straight to the emergency department) right away if you notice any of the following:

  • A persistent or worsening headache, particularly when associated with vomiting
  • Repeated vomiting that does not stop
  • Unusual drowsiness, difficulty rousing, or confusion
  • A seizure
  • New or worsening problems with vision, balance, or walking
  • In a baby - a tense or bulging fontanelle, accelerated head growth, or downward-deviation of the eyes
  • Redness, swelling, or tenderness along the line of the shunt under the skin
  • An unexplained fever in a child who has a shunt

If your child is difficult to rouse, or is having a seizure, this is an emergency, go to the nearest emergency department or call the emergency services immediately.

More information from trusted sources

  • Hydrocephalus Association — A US-based non-profit dedicated to supporting families and funding research. They provide comprehensive plain-language guides, family support and a helpline.
    https://www.hydroassoc.org ↗
  • American Association of Neurological Surgeons — Patient Information — The patient education pages of the professional society, including a detailed plain-language guide to hydrocephalus.
    https://www.aans.org/Patients/Neurosurgical-Conditions-and-Treatments/Hydrocephalus ↗
  • HealthyChildren.org (American Academy of Pediatrics) — Trusted patient and family information from the American Academy of Pediatrics, covering many paediatric conditions.
    https://www.healthychildren.org ↗
  • Society for Research into Hydrocephalus and Spina Bifida (SRHSB) — An international scientific society, useful if you want to follow research developments in paediatric hydrocephalus.
    https://www.srhsb.com ↗