Hydrocephalus comes from the Greek words hydro meaning water and cephalus meaning head. Hydrocephalus is an abnormal accumulation of cerebrospinal fluid (CSF)–– within cavities in the brain called ventricles. Cerebrospinal fluid is produced in the ventricles and in the choroid plexus and circulates through the ventricular system in the brain, and is absorbed into the bloodstream. It contains nutrients and proteins necessary for the nourishment and normal function of the brain, and carries waste products away from surrounding tissues. Hydrocephalus occurs when there is an imbalance between the amount of CSF that is produced and the rate at which it is absorbed. As the CSF builds up, it causes the ventricles to enlarge and the pressure inside the head to increase.
Hydrocephalus may be congenital or acquired. Congenital hydrocephalus is present at birth and may be caused by either events or influences that occur during fetal development, or genetic abnormalities. Acquired hydrocephalus develops at the time of birth or at some point afterward. This type of hydrocephalus can affect individuals of all ages and may be caused by injury or disease.
Hydrocephalus may also be communicating or non-communicating. Communicating hydrocephalus occurs when the flow of CSF is blocked after it exits the ventricles. This form is called communicating because the CSF can still flow between the ventricles, which remain open. Non-communicating hydrocephalus, also called "obstructive" hydrocephalus, occurs when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles. One of the most common causes of hydrocephalus is "aqueductal stenosis." In this case, hydrocephalus results from a narrowing of the aqueduct of Sylvius, a small passage between the third and fourth ventricles in the middle of the brain.
Symptoms of congenital hydrocephalus (present at birth):
- breathing difficulties
- arm and leg muscles may be stiff and prone to contractions
- some developmental stages may be delayed, such as sitting up or crawling
- poor feeding
- the head seems larger than it should be
- pupils of the eyes may be close to the bottom of the eyelid, sometimes known as "the setting sun"
- possible seizures
Symptoms of acquired hydrocephalus, which develops after birth, are:
- confusion, disorientation, or both
- drowsiness and lethargy
- lack of appetite
Cerebrospinal fluid (CSF) flows through your brain and spinal cord in normal conditions. Under certain conditions, the amount of CSF in your brain increases. The amount of CSF can increase when:
- a blockage develops that prevents CSF from flowing normally
- there is a decrease in the ability of blood vessels to absorb it
- your brain produces an excess amount of it
Shunts may also be used for normal pressure hydrocephalus. However, shunts may not be suitable for some patients. Other procedures may be carried out to check suitability:
Lumbar puncture - some of the cerebrospinal fluid is removed from the base of the spine. If this improves the patient's gait or mental abilities, fitting a shunt will probably help.
Lumbar infusion test - a needle is inserted through the skin of the lower back into the spine. Measurements are taken of CSF pressure as fluid is injected into the spine. Patients usually benefit from having a shunt fitted if their CSF pressure is over a certain limit.
There are many resources available to provide emotional and medical support as you parent a child with hydrocephalus. Children with developmental problems due to hydrocephalus may be eligible for government-sponsored health care and other support services. Check with your state or county social services agency. Hospitals and voluntary organizations serving people with disabilities are good resources for emotional and practical support, as are doctors and nurses.