The meninges (say: muh-NIN-jeez) cover and protect the brain and spinal cord. Meningitis happens when the meninges swell or get irritated.
There are different kinds of meningitis, but most of the time it is caused by germs, especially bacteria and viruses. Someone with meningitis is very sick and may have a very bad headache, stiff neck, and fever. Meningitis not only makes someone feel sick, it can affect the person's ability to think and learn. But many people recover from the infection without permanent problems.