Hydrocephalus
A build-up of cerebrospinal fluid in the chambers of the brain that raises the pressure inside the skull. It affects babies, children and adults for different reasons, and it is usually treatable.
Greenslopes Private Hospital, Brisbane
Watkins Medical Centre, Spring Hill, or telehealth
A current GP or specialist referral is needed
At a glance
A blockage in the fluid pathways, poor absorption, or, rarely, overproduction.
Present from birth, or after bleeding, infection, injury or a tumour.
Obstructive, communicating, and normal pressure hydrocephalus (NPH) in older adults.
Each is assessed differently.
CT or MRI; lumbar puncture, a drainage trial or overnight pressure monitoring where the picture is uncertain.
Shunt surgery, or an endoscopic third ventriculostomy.
Lifelong review of a shunt.
What hydrocephalus is
The brain makes about half a litre of cerebrospinal fluid a day, circulates it through a series of chambers and channels, and reabsorbs it into the bloodstream. Hydrocephalus is what happens when that circuit is interrupted.
When fluid cannot drain, it accumulates in the ventricles, the chambers inside the brain, which enlarge and press outward. In a baby, whose skull can still expand, the head grows. In an older child or adult the skull cannot give, so the pressure rises and causes symptoms. Hydrocephalus is called obstructive when a physical blockage is the cause, and communicating when fluid can circulate but is not being absorbed properly, as can happen after bleeding, infection or head injury.
Normal pressure hydrocephalus (NPH) is a form seen in older adults in which the ventricles are enlarged but the pressure is not obviously high. It causes a characteristic combination of walking difficulty, memory decline and bladder urgency that can be mistaken for dementia or Parkinson’s disease, and it is one of the few causes of those symptoms that can be treated.
Some people have enlarged ventricles that have been stable for years without symptoms, sometimes called arrested or compensated hydrocephalus. These are watched rather than treated, with clear advice about what would change that.
Symptoms
Symptoms depend on age and on how quickly the pressure has risen. In someone with a shunt, the same symptoms can mean the shunt is not working.
- Adults and older children: headache worse in the morning or on lying down, nausea and vomiting, blurred or double vision, drowsiness, difficulty with balance and walking
- Babies: a rapidly enlarging head, a bulging soft spot, irritability, poor feeding, vomiting, eyes that drift downward
- Older adults with NPH: a slow, shuffling, wide-based walk, forgetfulness, and urinary urgency or incontinence, developing over months
- Anyone with a shunt: headache, vomiting, drowsiness, fever or redness along the shunt tubing
Drowsiness, persistent vomiting or a severe headache in someone with hydrocephalus or a shunt needs an emergency department the same day. Call 000 if they are hard to wake.
How it is diagnosed
CT or MRI shows the enlarged ventricles and often the cause. For NPH, where the decision to operate is less clear-cut, a lumbar puncture that removes a volume of fluid, or a few days of drainage through a lumbar drain, tests whether walking improves when the pressure is lowered. Overnight monitoring of the pressure inside the head through a fine probe is used where the diagnosis remains uncertain, so that a shunt is not implanted on a guess.
The scan is on the screen, the options are set out on equal terms, and nothing is booked until you have had time to think.
Treatment options
Treatment either drains the fluid to somewhere it can be absorbed, or opens a new path for it inside the brain. The cause of the blockage, where there is one, is treated as well.
- Shunt surgeryA thin tube with a valve is placed into a ventricle through a small opening in the skull and tunnelled under the skin to the abdomen, where the fluid is absorbed. Modern valves can be adjusted from outside with a magnet. The usual treatment for most forms of hydrocephalus, including NPH.
- Endoscopic third ventriculostomyUsing an endoscope through a keyhole opening, a small hole is made in the floor of the third ventricle so that fluid can bypass a blockage. Suits obstructive hydrocephalus in the right anatomy, and avoids having a shunt at all.
- Treating the causeRemoving a tumour or cyst that is blocking the fluid pathways may resolve the hydrocephalus without a shunt.
- MonitoringInterval scans and review for stable, compensated hydrocephalus that is not causing symptoms.
- Shunt revisionShunts can block, disconnect or become infected. Revision replaces the faulty part; infection is treated with antibiotics and, usually, temporary removal of the shunt.
Not every option applies to every person. Which ones apply to you, and in what order, is explained at the consultation and confirmed in writing before anything is booked.
Recovery and follow-up
Shunt surgery is a short operation with a short stay. Living with a shunt is a longer matter, and knowing the warning signs is part of it.
Most people go home one to three days after shunt surgery, with small wounds on the scalp, the neck and the abdomen. In NPH, walking often improves within days and memory more gradually over weeks; not every symptom responds. After an endoscopic third ventriculostomy the stay is similar and there is no hardware to look after.
A shunt is for life. It is reviewed at the rooms, with scans when symptoms suggest a problem rather than on a fixed schedule, and its settings can be adjusted at a visit if the valve is programmable. Carry a note of the shunt type; some valves need resetting after an MRI.
Children with hydrocephalus
Children are treated at the Queensland Children’s Hospital and reviewed as they grow, since a shunt placed in infancy may need lengthening or revising. The child’s paediatrician stays involved throughout.
Dr Gert TollessonNeurosurgeon, Brisbane
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