Hydrocephaly, also referred to as hydrocephalus, is a condition characterized by an unusual accumulation of fluid in the brain's ventricles. This fluid often builds up under increased pressure, potentially harming the brain. Hydrocephalus can develop before birth or at any point afterward, and it can be caused by various factors such as a genetic defect, brain hemorrhage, infection, tumor, or head trauma. Most hydrocephalus cases result from blockages in the cerebrospinal fluid (CSF) flow within the ventricular system. In cases involving birth defects, the obstruction is typically physical, leading to the condition. Hydrocephalus frequently occurs alongside spina bifida (meningomyelocele).Hydrocephalus ex-vacuo refers to a situation where brain damage or injury leads to a reduction in brain tissue, but the CSF pressure remains normal. On the other hand, normal pressure hydrocephalus (NPH) happens when there is a slow blockage of CSF pathways in the brain, causing the ventricles to enlarge while the CSF pressure stays within normal limits. NPH is often identified by symptoms such as memory impairment, difficulty walking, and general slowing of activity.In older adults or individuals with certain conditions, the entire brain might shrink, and the CSF fills the resulting empty space. This occurrence is not due to hydrocephalus. The symptoms and signs of hydrocephalus vary with age. In infants, the most noticeable sign is typically an unusually large head, which is why measuring a baby's head at well-baby visits is crucial. Other symptoms in infants include vomiting, lethargy, irritability, difficulty looking upwards, and seizures. In older children and adults, head enlargement doesn't occur, but symptoms like headaches, nausea, vomiting, and sometimes blurred vision may appear. Additional issues may include balance problems, delays in walking or talking, and poor coordination. As hydrocephalus progresses, irritability, fatigue, seizures, personality changes, concentration difficulties, drowsiness, and double vision might develop.Treating hydrocephalus usually involves placing a shunt to allow excess fluid to drain and alleviate brain pressure. The shunt, a flexible plastic tube with a one-way valve, is inserted into the brain's ventricular system to redirect CSF to another body area for absorption into the bloodstream.The prognosis for hydrocephalus depends on its cause and the timing of diagnosis and treatment. Many children who receive treatment lead normal lives with minimal limitations. However, some may experience impairments in language and cognitive functions. Issues with shunts, such as infections or malfunctions, may necessitate shunt revisions.Hydrocephalus is sometimes described as "water on the brain." The term "hydrocephalus" originates from the Greek words meaning "watery head."
