Science Questions

How bad does meningitis affect the brain? I had it when I was younger and think it might have affected my ability to remember things. Wynn in Northampton

There are a couple of issues with this. Meningitis comes in two flavours or two forms. There's a viral flavour and a bacterial flavour and by far and away the most serious form of meningitis is the bacterial form. This is because in this instance you have bacteria physically growing and multiplying in the fluid that surrounds the brain. When they do that they secrete lots of factors that promote intense inflammation and can damage the underlying brain. One of the things they do is cause inflammation around the nerves that flow through that space and these include the auditory nerve that supplies your ears and connects your ears to the brain. If you have a lot of inflammation around those nerve roots, it can unfortunately pinch them off and cause permanent deafness. There are other problems of course. If people aren't treated in time with meningitis it can be very serious and can result in people dying. Fortunately we now have vaccines that have been introduced and this has brought the mortality right down. In the UK for instance in young children, there was a type of meningitis caused by meningitis strain C and that was introduced as a vaccine about five years ago. Since then there's been a dramatic reduction in the number of cases. Among adults the most common form is strain B and this still remains a major problem and there is no consistent vaccine for this, so you should be on the look out for signs and symptoms. These include a non-specific feeling grotty for a few days first, and then you start to get a headache. Then you can start to feel quite sick and get scared of the light and your neck can become very very stiff. Then people start to develop a rash which is non-blanching. In other words if you press on the rash with a wine glass or something and look through the glass, the rash doesn't go away. If you have those signs and symptoms, you ought to maybe get checked out by a doctor. Now the other flavour of meningitis I mentioned is viral meningitis and this isn't necessarily so bad. This is when a virus attacks the membranes that surround the brain and it causes many of the same symptoms but usually these cases are self-limiting, which means they just go away and get better of their own accord. Sometimes if it's caused by the herpes virus which is the same virus that can cause cold sores, then you might need to go into hospital for a while and have a drug called acyclovir which knocks it on the head. But thankfully most of the cases don't have long term sequelae, not like the bacterial form.

April 2006