Hydrocephalus is a condition involving the abnormal accumulation of cerebrospinal fluid in and around the brain.
The brain and spinal cord are collectively known as the central nervous system (CNS). A fluid called cerebrospinal fluid (CSF) surrounds the CNS. The CSF protects and nourishes the brain. The ventricles are a series of chambers inside the brain that contain and help circulate CSF. Normally, the CSF flows through the ventricles in the brain. It is then reabsorbed into the bloodstream through the membranes that line the skull and spinal canal.
Hydrocephalus may be classified as obstructive or nonobstructive. Obstructive hydrocephalus occurs when the circulation of CSF in the brain is blocked. Nonobstructive hydrocephalus occurs when something interferes with the reabsorption of CSF into the bloodstream. As the CSF accumulates, the ventricles enlarge. They press on the soft tissue of the brain and cause the symptoms of hydrocephalus.
Obstructive hydrocephalus can be caused by:
Nonobstructive hydrocephalus can be caused by:
Premature infants are at increased risk for developing this condition. This is because premature babies are more likely to develop bleeding inside or around the brain. The blood can block the membranes that reabsorb CSF, causing hydrocephalus. This risk rises with the degree of prematurity.