An excessive amount of cerebrospinal fluid, usually under increased pressure, within the skull. The condition may be present at birth, when it is often associated with other abnormalities, such as spina bifida, or it may develop as a result of major head injury, brain haemorrhage, infection (such as meningitis), or a tumour. With congenital hydrocephalus, the main feature is an enlarged head that continues to grow rapidly. Other features include rigidity of the legs, vomiting, epilepsy, irritability, lethargy, and the absence of normal reflex actions. If it is not treated, hydrocephalus progresses to severe brain damage, which may result in death within weeks. When the condition occurs later in life, symptoms include headache, vomiting, loss of coordination, and the deterioration of mental function. In most cases, treatment of hydrocephalus is by draining the fluid from the brain to another part of the body, such as the abdominal cavity, where it can be absorbed.


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