Water on the brain, known more formally as hydrocephalus, is a neurological condition characterized by a buildup of cerebrospinal fluid in the brain. This fluid normally delivers nutrients to the brain and acts as a shock absorber to protect the brain, but when it builds up, it can damage the soft tissues of the brain and increase the pressure inside the skull, leading to a variety of neurological problems. Hydrocephalus is the leading cause of brain surgery among children, and numerous people all over the world live with this condition, some of whom manage to live very successfully despite substantial alterations to their brain structure.
In some cases, water on the brain is congenital, caused by defects in the structure of the brain which impair the circulation and drainage of cerebrospinal fluid. Other cases are acquired, caused by damage to the brain such as a stroke or traumatic brain injury. In both cases, the buildup of fluid can be clearly seen in imaging studies of the brain, and sequential studies can be used to determine how rapidly the buildup is occurring.
When someone has the form of water on the brain known as communicating hydrocephalus, the cerebrospinal fluid can circulate successfully between the ventricles of the brain, but it cannot drain properly. In noncommunicating hydrocephalus, the circulation of the fluid is blocked. As the brain keeps producing its daily complement of cerebrospinal fluid, the water on the brain starts to cause neurological problems because it has no escape route.
In children, the earliest sign of hydrocephalus can sometimes be an expansion in head size, caused by the skull's increased growth to accommodate the larger volume of the brain and cerebrospinal fluid. Water on the brain can also cause symptoms like vomiting, nausea, vision problems, seizures, sleepiness, and developmental delays. When these symptoms present in a patient, a doctor can order a medical imaging study to look at the brain and learn more about what is causing the patient's symptoms.
It is not possible to cure water on the brain, but the condition can be treated. Treatment involves inserting a shunt into the brain to provide a drainage method. The shunt is a flexible plastic tube which drains to another portion of the body which can reabsorb and eventually express the cerebrospinal fluid. Placing a shunt must be done with care to avoid causing brain damage, and the shunt needs to be monitored to confirm that it is draining properly.