Inflammation of the meninges (membranes covering the brain and spinal cord), usually due to infection. Viral meningitis tends to occur in epidemics in the winter; it is relatively mild. Bacterial meningitis is life-threatening. It is mainly caused by the bacterium, and type B and C bacteria. The infection usually reaches the meninges via the bloodstream from an infection elsewhere in the body. Less commonly, it passes through skull cavities from an infected ear or sinus, or from the air following a skull fracture. The main symptoms are fever, severe headache, nausea and vomiting, dislike of light, and a stiff neck. In viral meningitis, the symptoms are mild and may resemble influenza. In bacterial meningitis, the main symptoms may develop over only a few hours, followed by drowsiness and, occasionally, loss of consciousness. In about half the cases of meningococcal meningitis, there is also a rash under the skin that does not fade with pressure (see glass test). The rash starts as pin-prick spots that can join to give a bruise-like appearance. To make a diagnosis, a lumbar puncture is performed. Viral meningitis needs no treatment and usually clears up within a week or two with no after-effects. Bacterial meningitis is a medical emergency. It is treated with intravenous antibiotic drugs. With prompt treatment, a full recovery is usually made. However, brain damage may occur in some cases. Vaccines are now given to protect children against 2 of the major types of bacterial meningitis: those caused by the bacterium and the type C bacterium (see immunization). For other types of bacterial meningitis, antibiotic drugs are given as a protective measure to people who have come into contact with the infection.


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