Hydrocephalus is a buildup of fluid inside the skull that leads to swelling of the brains.


The word hydrocephalus is derived from the Greek words hydro (water) and kephale (head).

About hydrocephalus, most people have a picture in mind of a baby with a very large head. Something that is much less well known, is that hydrocephalus can occur at any age. Hydrocephalus can cause brain damage, as a complication of bleeding, injury, inflammation or tumor. It can lead to neurological (physical), emotional, behavioral and or learning disabilities.

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We speak of hydrocephalus or hydrocephaly when the cavities in the brains contain more cerebrospinal fluid than they should contain. An adult brain produces about 500 cc per day (half a liter) of cerebrospinal fluid in the spaces within the brains, the brain cavities, also known as ventricles. The skull is an enclosed space and excess cerebrospinal fluid increases the pressure in the brains. This pushes the brains against the skull and causes damage to the brain tissue. Brain functions may be affected. The pressure in the brains may be increased by:

  • Disturbed drainage of cerebrospinal fluid
  • An increase in the production of the liquid
  • A blockage of the drainage within the head which causes the brains to swell. This is also called brain edema.


Brain fluid

Brain fluid is also known by the names (brain-) spinal fluid or Cerebrospinal fluid (CSF). It is the liquid that is located in and around the brains and spinal cord. The main function of cerebrospinal fluid is shock absorption.


It protects the brains and the spinal cord. Another function of the fluid is the transport of nutrients and removal of waste. The production of cerebrospinal fluid takes place in the choroid plexus by filtering the blood. The fluid circulates in the brains and spinal cord and is finally reabsorbed into the bloodstream

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Causus of hydocephalus

Hydrocephalus usually arises as a result of a brain haemorrhage in the first days of life of premature newborn. However, there are also other causes. Hydrocephalus comes forward as a result of a collection of diseases. For each patient, the cause different and the consequences are different.


When there is a tumor in the production organ of the cerebral flued (this tumor is called a plexuspappilloma), too much cerebrospinal fluid is being created.


Furthermore, hydrocephalus can be caused by a disturbance in the drainage of cerebrospinal fluid. This may be caused by meningitis or by bleeding in the ventricles, or bleeding between the meninges; subarachnoid hemorrhage or, in short, SAH. However, it may also be congenital. The congenital variant of hydrocephalus affects one in every 500 babies.


The cause of congenital hydrocephalus that occurs most is a narrowing of the connection between the third and fourth brain chamber (aqueduct of Sylvius). Such a narrowing is called "aqueduct Stenosis". In the picture below this is referred to as Cerebral Aqueduct.





 It may be caused by:

  • Hereditary malformations
  • Tumors
  • Haemorrhages
  • Infections


Hydrocephalus can also develop in combination with other birth defects, such as Arnold-Chiari syndrome and Dandy-Walker syndrome. In the case of the Dandy-Walker Syndrome there is a disturbance in the development of the fourth brain chamber.


Symptoms of hydrocephalus

The symptoms vary by age, but also depend on how much brain tissue is damaged and what is the cause of the increased amount of brain fluid.


In babies:

  • Head is growing too fast
  • Fontanelle (the soft spot between the skull bones) is bulging
  • Sunset sign
  • Drowsiness
  • Irritability
  • Veins on the head are swollen
  • Convulsions occasionally
  • Vomiting
  • Typical high-pitched tone of short crying
  • Difficulties to feed the child


In adults and older children in whom the skull is already closed the head can no longer expand and you will see other complaints:

  • Nausea and vomiting
  • Headache
  • Lethargy, drowsiness, sleeping a lot
  • Impaired coordination and difficulty walking
  • Blurred or double vision or uncontrollable eye movements
  • Change in facial expression
  • Decreased bladder control; trouble keeping the urine
  • Muscle spasms
  • Change in behavior, thinking, memory


In the picture below, you see a CT recording with hydrocephalus. The ventricles are the black spots in the middle. They are enlarged by an excess of cerebrospinal fluid.




Picture by: Lucien Monfils




If a person with hydrocephalus does not get a treatment, the chance that this person will die is very large (60%). The goal of treatment is to reduce or prevent brain damage by improving the flow of cerebrospinal fluid.

If there are signs of an infection antibiotics will be prescribed.


In case hydrocephalus is caused by a brain tumor an attempt will be made to remove this brain tumor. If the cause is a narrowing of the passageway between the third and fourth brain room (aqueduct stenosis) doctors will try to widen the corridor by an operation.


If these treatments have little or no result, often treatment with a drain (tube) is chosen. This drain leads excess fluid into the heart or into the abdominal cavity, In this case we speak of an internal drain. An external drain carries the liquid away to a reservoir outside of the body.




A special form of hydrocephalus is the Normal Pressure Hydrocephalus (NPH).

The cause is probably an impaired absorption of cerebrospinal fluid in the elderly. The confusing of this disease is that it looks like normal effects of aging like dementia: mental decline, difficulty walking, difficulty with balance and equilibrium and incontinence, frequent urination. The syndrome occurs insidiously. The normal process of aging and Alzheimer's disease have the effect of expanding the ventricles. Therefore DPH is difficult to diagnose. A brain scan, combined with other studies, for example a lumbar puncture, and combined with the three main complaints will often offer more clarity. Read more here