Hydrocephalus factsheet
Introduction
Hydrocephalus is when too much cerebrospinal fluid (CSF) builds up around the brain. CSF is a clear fluid that:
- protects the brain and spinal cord
- carries nutrients
- removes waste.
When CSF can’t flow properly, it builds up and causes pressure in the brain.
In babies, this pressure can make the head grow larger because their skull bones haven’t joined together yet.
In older children and adults, the skull bones are already fused, so the head doesn't grow.
It can be caused by genetic conditions or problems with how the brain and spine develop, including:
- severe spina bifida or neural tube conditions – when the spinal cord is exposed and CSF doesn’t flow properly
- chiari 2 malformation – when part of the lower brain pushes into the spinal canal and blocks the flow of CSF
- craniosynostosis – when the skull bones close too early, before the brain has finished growing.
Hydrocephalus can also happen later in life due to:
- head injury
- brain bleeds
- brain tumours
- meningitis – inflammation in the tissue that protects the brain and spinal cord.
Signs and symptoms
The most common symptoms of hydrocephalus are:
- headache
- nausea
- vomiting
- seizures.
In babies:
- larger head size
- bulging or firm fontanelle - the soft spot on top of their head
- poor feeding
- sleepiness
- eyes turning inwards.
For older children and teenagers:
- blurred or double vision
- trouble concentrating
- clumsiness or poor coordination
- confusion
- loss of bladder or bowel control.
Hydrocephalus can also affect learning and vision as your child grows.
Diagnosis
If your child has symptoms, their doctor may order scans and tests to check the amount of fluid in the brain.
These may include:
- ultrasound – used during pregnancy or in babies whose fontanelle is still open
- CT scan - to check for spaces around the brain where fluid is building up
- MRI – to get a more detailed picture of the brain and fluid buildup
- lumbar puncture – checks fluid pressure from the spine.
Treatment
Hydrocephalus is treated by placing a device called a ventricular peritoneal (VP) shunt. It drains the extra fluid from the brain to the belly.
The shunt is a thin tube placed under the skin. It has a one-way valve that controls the flow of fluid. The tubing usually runs from the head, down the neck, and into the belly. A coil of extra tubing is stored in the belly so it can grow with your child.
A shunt will not cure hydrocephalus, but it will relieve pressure and help the head and brain to grow normally.
Your child will have regular appointments with their treatment team and local doctor to make sure the shunt is working properly.
Shunt problems
A shunt may stop working if the tubing is:
- blocked
- kinked
- disconnected.
A damaged valve will also stop the shunt from working properly.
Warning signs in babies:
- fast head growth
- bulging or tense fontanelle until the bones close, around 18 months
- swelling and pain along the shunt, especially at the side of the neck
- irritability
- nausea and vomiting
- crossed eyes
- sun-setting eyes – eyes that focus downwards
- pauses in breathing
- excessive sleepiness
- trouble feeding or swallowing.
Warning signs in children:
- headache
- blurred vision
- drowsiness or low energy
- fainting
- confusion.
Other possible signs:
- trouble walking and changes in mobility
- memory problems or learning problems
- developmental delay
- new or worsening seizures
- back pain or worsening scoliosis
- changes in bowel or bladder functioning
- changes in hearing.
A shunt malfunction can be life threatening. Call triple zero (000) for an ambulance or go to the emergency department if your child shows these signs.
Shunt infection
Infection can happen at any time but is more common after inserting or changing a shunt.
Signs of infection include:
- fever
- stiff neck
- redness or swelling near the shunt
- fluid leaking from the wound
- tenderness along the tubing
- belly pain.
A shunt infection can be life threatening. Call triple zero (000) for an ambulance or go to the emergency department if your child shows these signs.
Management
Hydrocephalus and learning development
Some children with hydrocephalus have learning delays or difficulties as they grow.
They may have trouble with:
- organising
- planning
- starting tasks
- problem solving
- handling new or unfamiliar tasks.
This is different for every child and can affect school, home life, self-care, and future work.
To support learning:
- provide a structured routine with lots of repetition
- getting help for your child to stay focused in class or at work.
Early therapy and learning support can make a big difference. Speak to your child’s treatment team about early intervention services.
Hydrocephalus and eyesight
Hydrocephalus can affect eyesight. This may include:
- nystagmus – fast, uncontrolled eye movements
- optic atrophy – ongoing damage to the optic nerve
- squinting or crossed eyes
- reduced vision
- papilloedema – swelling where the optic nerve meets the back of the eye.
A new squint may mean the shunt isn’t working properly. Regular eye checks help monitor eye health and brain pressure.
Hydrocephalus and seizures
Children with hydrocephalus have a higher risk of seizures. These can happen at any time. Some children may need medication if seizures are frequent.
Seizures can also be a sign that the shunt is infected.