hydrocephalus (water on the brain)

Accumulation of cerebrospinal fluid inside the skull as a result of a blockage. The cranial sutures of babies do not close before the age of one or two, and as a result an increase of cerebrospinal fluid in the ventricles causes the skull to become enlarged. However, once the cranial sutures have knitted together the skull can no longer swell in this way and therefore the pressure inside the skull is increased; this is known as internal hydrocephalus. The major causes of hydrocephalus are congenital abnormalities of the nervous system, such as spina bifida. Hydrocephalus may result if the foetus is infected with toxoplasmosis or rubella, or if it contracts meningitis in its first year of life. It is very important to identify and treat the disease at an early stage. The first symptom in babies is that the skull grows too large. To detect this, the circumference of the skull is continually measured in post-natal clinics. Irritability and vomiting set in later as a result of increased pressure on the brain; finally brain cells die, and mental deficiency occurs because of cerebral atrophy. The symptoms of increased pressure on the brain in older children are as follows: headache, vomiting, dullness, eye abnormalities and sometimes epilepsy. When hydrocephalus occurs, it is first necessary to look for the cause. If the cause can be treated, this should be done. The hydrocephalus itself is treated by neurosurgery and the cerebrospinal fluid drawn off, perhaps using a shunt. The patient must be carefully monitored over a period of years.