Science Questions

what causes hydrocephalus in babies, babies with large heads ? John

Hydrocephalus is where there's excessive amount of fluid in the skull cavity, within the brain, and that can be due to a number of problems. In children the commonest cause is normally is that there's either been some damage to the brain, that the fluid filled cavities have got bigger as a result or that there's an obstruction to flow. We make fluid within our brain all the time, and it circulates around a series of chambers in the brain. If there is an obstruction to that then clearly the production doesn't stop, there's a blockage and the pressure goes up, hence you get hydrocephalus. In children what happens is because the skull hasn't yet fused the head gets bigger so you actually get these large heads with hydrocephalus in childhood. Whereas in adulthood you've obviously got a thick skull and what tends to happen if you've got a blockage in the system is that you tend to get raised pressure inside the head which gives you a very severe headache and you need to do something about it fairly urgently. To treat it you first need to find what is causing it. Normally you either then remove the blockage, or to put in a drain, called a shunt, so that you take the high pressure out of the system. You drain the fluid to another cavity, normally the abdomen.

October 2004