What causes hydrocephalus?
A variety of medical problems can cause hydrocephalus. In many children the problem is there at birth - this kind of hydrocephalus is referred to as congenital. Most cases of congenital hydrocephalus are thought to be caused by a complex interaction of genetic and environmental factors. Hydrocephalus that develops later in life in some children, and even in adults, but is caused by a condition that existed at birth, is still considered a form of congenital hydrocephalus.
When hydrocephalus develops after birth and is caused by a factor such as head injury, meningitis or a brain tumor, it is termed acquired hydrocephalus. Parents must not blame themselves for their child's hydrocephalus. In almost all cases the circumstances contributing to a child's condition are beyond the parent's control.
Hydrocephalus can be broadly classified as being caused by disturbance to normal production, flow or absorption of cerebrospinal fluid. The most common cause of hydrocephalus is disruption to cerebrospinal fluid circulation, which can be secondary to tumor, hemorrhage, infection or congenital malfomations. It can also be caused by overproduction of cerebrospinal fluid.
Hydrocephalus is the result of an imbalance between the formation and drainage of cerebrospinal fluid (CSF). Approximately 500 milliliters (about a pint) of CSF is formed within the brain each day, by structures called choroid plexus, with epidermal cells lining chambers called ventricles. Once formed, CSF usually circulates among all the ventricles before it is absorbed and returned to the circulatory system. The normal adult volume of circulating CSF is 150 ml, so that the CSF turn-over rate is more than three times per day. Production is independent of absorption, and reduced absorption causes CSF to accumulate within the ventricles.
Reduced absorption most often occurs when one or more passages connecting the ventricles become blocked, preventing movement of CSF to its drainage sites in the subarachnoid space just inside the skull. This type of hydrocephalus is called "noncommunicating." Reduction in absorption rate can also be caused by damage to the absorptive tissue. This type is called "communicating hydrocephalus."
Both of these types lead to an elevation of the CSF pressure within the brain. This increased pressure squeezes the soft tissues of the brain, distorting and damaging them. In infants whose skull bones have not yet fused, the intracranial pressure is partly relieved by expansion of the skull, so that symptoms may not be as dramatic. Both types of elevated-pressure hydrocephalus may occur from infancy to adulthood. A third type of hydrocephalus, called "normal pressure hydrocephalus," is marked by ventricle enlargement without an apparent increase in CSF pressure. This type affects mainly the elderly.
More information on hydrocephalus
What is hydrocephalus? - Hydrocephalus is the lack of absorption, blockage of flow, or overproduction of the cerebral spinal fluid (CSF) that is found inside of the ventricles inside of the brain.
What causes hydrocephalus? - Hydrocephalus can be broadly classified as being caused by disturbance to normal production, flow or absorption of cerebrospinal fluid.
What're the symptoms of hydrocephalus? - The symptoms of hydrocephalus include irritability, fatigue, seizures, and personality changes, drowsiness, and double vision.
How is hydrocephalus diagnosed? - Hydrocephalus may be diagnosed before birth by prenatal ultrasound, a diagnostic imaging technique which uses high-frequency sound waves.
What's the treatment for hydrocephalus? - Treatment of hydrocephalus depends on its cause. Medications are used to slow the rate of cerebrospinal fluid production temporarily.