How does hydrocephalus affect the brain?

Answer: Hydrocephalus is a medical disorder that occurs when the ventricle system is blocked and the brain is damaged as a result.

hydrocephalus ventricles

Hydrocephalus (hydro, water; cephalus, head) is a medical condition generally affecting young infants. Some common symptoms of hydrocephalus include an enlarged skull and cognitive deficits. In adults, it may cause headaches, cognitive impairment, or seizures. Because it often affects the entire brain, hydrocephalus may result in many other symptoms.

Within the brain is a system of fluid filled spaces called ventricles. These ventricles are filled with a high osmolarity liquid called cerebrospinal fluid, which is produced by the ependymal cells lining the inside of the ventricles. The cerebrospinal fluid is mostly water, with a high concentration of sodium and chloride ions, in excess of 100 mM.

The largest ventricles are the two lateral ventricles, which are connected in the middle by the third ventricle. This ventricle is continuous with the spinal cord, and is connected via the central aqueduct and the fourth ventricle. At this point, some injury or damage to the structure may prevent the cerebrospinal fluid from moving into the spinal cord. If so, the fluid would accumulate in the brain ventricular space, causing the brain to expand. In infants, because the bones of the skull are not completely fused together, the expansion of the brain tissue may cause the skull to expand. This helps reduce the damage from brain swelling, and accounts for the enlarged head that is so often seen in infants with hydrocephalus.

The most effective treatment for hydrocephalus is to provide a drainage shunt from the ventricles down into the peritoneal cavity. This allows the cerebrospinal fluid to leave the ventricular system and relieves the pressure on the brain.