Fluid normally flows around the spinal cord and the brain and is absorbed in the blood stream. This fluid serves as a cushion to protect the spinal cord and brain from injury. It also contains nutrients and proteins to nourish the brain and help it function, and it carries waste products away to be absorbed by the bloodstream. When this fluid is produced faster than it can be absorbed or is blocked and collects inside the brain, the condition is called hydrocephalus. As the fluid builds up, it causes the ventricles to enlarge and the pressure inside the head to increase.


If it is present from birth it causes a newborn to have an unusually large head.


Causes and Risk Factors

Hydrocephalus that is present at birth is probably caused by environmental and genetic factors. When the condition develops after birth it is usually the result of a disease (such as meningitis), injury to the head, tumors, cysts or bleeding inside the chambers of the brain


A doctor may order the following procedures to diagnose the condition accurately:

  • Skull X-rays. In addition to the enlargement of the skull caused by hydrocephalus, X-rays can reveal the distinctive appearance of the bones that shows an increase in the pressure inside the skull over a period of time.
  • Ultrasound. This is helpful in showing whether or not there is bleeding inside the skull and the chambers of the brain.
  • Computed tomography (CT) scans. These will show the size of the chambers inside the brain and possibly where a blockage is that prevents the flow of fluid around the brain and spinal cord. A CT scan will show cysts, tumors or an enlarged brain, if they are present.
  • Magnetic resonance imaging
  • Blood tests. These will help identify if there is an infection present, including infections that may be present at birth from viruses such as rubella or herpes.
  • Electroencephalogram (EEG). This test may be helpful if there are seizures.
  • Microscopic examination of the spinal fluid


There is no known way to prevent or cure hydrocephalus. Treatment will vary depending on what is causing the fluid to collect.

Options include:

  • Removing fluid to reduce the pressure inside the brain. This provides only temporary relief.
  • Surgery to put in a shunt to remove the spinal fluid. This is done when the condition is getting worse and putting growing pressure on the brain and skull. Not all forms of hydrocephalus get worse. Less invasive procedures, such as endoscopic third ventriculostomy (ETV), are growing in popularity as an alternative to traditional surgery.

After treatment, a child will need ongoing monitoring as he or show grows to ensure that infections do not develop. Hydrocephalus is often associated either with Dandy-Walker cysts or the Arnold-Chiari malformation. Chiari malformation is often associated with spinal bifida and syringomyelia, but it may also occur on its own. Both of these involve major malformations of the base of the brain where it connects with the spinal cord. In either case, a shunt is usually used to reduce the fluid buildup.