The brain and spinal cord are surrounded by a clear fluid known as cerebral spinal fluid, or CSF. The body is constantly producing new CSF and absorbing the fluid into the bloodstream. Sometimes a person can have too much CSF in all or part of the brain. This condition, known as hydrocephalus, can occur when the passages transporting CSF through the brain become blocked. It can also occur when the body fails to reabsorb CSF as quickly as necessary, or more rarely, when it produces too much fluid. There are several conditions that can cause too much brain fluid.
Congenital Brain Malformations
Some cases of hydrocephalus are caused by malformations of the brain present at birth. These may interfere with the circulation of CSF or with proper absorption of the fluid. While historically such conditions have had a low survival rate, doctors have had some success treating them in recent years, according to the Hydrocephalus Association.
Spina Bifida
Hydrocephalus is a common complication of the developmental disorder spina bifida. According to the National Institutes of Health, children born with spina bifida absorb CSF at a slower than normal rate.
Brain Hemorrhage
Bleeding in the brain, or brain hemorrhage, causes parts of the brain to swell. This swelling can press the narrow channels between ventricles closed, damming the flow of CSF. According to the National Institutes of Health, most cases of hydrocephalus occur because of a blockage in the flow of CSF or in its absorption.
Traumatic Head Injury
Most serious head injuries will produce some swelling within the brain. This can have the same effect as a hemorrhage, squeezing passages shut and blocking the flow of CSF.
Meningitis or Other Infections
According to MayoClinic.com, meningitis and other infections of the brain can interfere with absorption of CSF, leading to hydrocephalus.
Brain Tumor
Brain tumors, regardless of whether or not they are cancerous, can trigger hydrocephalus in several ways. A growing tumor may block the circulation of CSF by interfering with the channels through which it travels. A tumor can also interfere with reabsorption of CSF. More rarely, certain kinds of tumors can cause the body to produce CSF too quickly.
