Hydrocephalus

The term hydrocephalus is derived from two words (HYDRO = water, CEPHALUS = head). Hydrocephalus is a condition in which too much cerebrospinal fluid accumulates within the ventricles of the brain and may increase pressure within the cranium. The condition may occur at any age.

The human brain is encased within the skull of the cranium which provides it with significant protection. Inside the cranium, the brain floats in a sea of liquid, which is called cerebrospinal fluid (CSF). This fluid is constantly being produced in the brain and circulated around the brain and spinal cord in a regular pattern. The CSF is subsequently absorbed by mushroom-like structures over the brain called arachnoid villae, and is then returned to the bloodstream.

The amount of CSF within the brain remains fairly constant; consequently, the water pressure which contributes to the overall pressure inside the skull - known as the intracranial pressure (ICP) - also remains fairly constant.

Hydrocephalus occurs when CSF circulation is altered in some way. For instance, the flow of CSF may be obstructed, CSF may not be adequately reabsorbed into the bloodstream, or less often, too much CSF is produced.

Obstruction of CSF flow can be the result of a birth defect, brain tumor, infection, hemorrhage, or brain injury. In some infants, particularly those born with spina bifida, the condition may accompany other malformations of the brain or spinal cord. The ability of the brain to absorb CSF may be reduced by a previous infection (meningitis) or brain injury. The production of too much CSF is usually caused by a rare brain tumor called a choroid plexus papilloma.

Your neurosurgeon will obtain from you a medical history and perform a neurological examination. He or she will ask many questions to determine if your symptoms or those of a family member are caused by hydrocephalus. The neurological examination will also help determine how severe the condition is. Further tests such as an ultrasound (if the patient is an infant), computed tomography (CT) scan, or magnetic resonance imaging (MRI) may be ordered if they have not already been performed.

Hydrocephalus can be treated in many ways. The problem can be treated directly (by removing the cause of CSF obstruction or overproduction if one can be found) or indirectly (by diverting the fluid buildup to somewhere else, typically into another body cavity by implanting a device known as a shunt that can divert the excess CSF away from the brain). The place into which the CSF is diverted is usually the peritoneal cavity (the area surrounding the abdominal organs).

American Association of Neurological Surgeons / Congress of Neurological Surgeons

Hydrocephalus

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