I am having my fifth bout of viral meningitis within the past 15 years. Some cases have been more severe than others, and fortunately this one is not as bad as some in the past. I am a 40-year-old woman and am disturbed and puzzled about why this keeps recurring. I've developed sinus trouble the past few years. Can that bring it on? Would any test help find out what's at the bottom of this?

Nancy

"Meningitis" is an inflammation of the meninges, the membranes covering the brain and spinal cord. Usually, meningitis is due to an infection, but there are other causes, including tumors and toxic chemicals. The most feared form of meningitis is due to bacteria, usually pneumococcus or meningococcus. In these infections, the patient dies unless he or she receives prompt antibiotic therapy. In contrast, viral meningitis (also known as "aseptic meningitis") usually gets better without any treatment. The patient usually has severe headache, fever and possibly a stiff neck. In severe cases, there can be some changes in mental function, though this is somewhat uncommon.

In most cases, after a patient recovers from viral meningitis, it never recurs. Occasionally, a person may have many recurrences. I have seen several patients who had more recurrences than the five you had over 15 years. It is impossible to say without examining you and getting more details, but you may have a syndrome called benign recurrent lymphocytic meningitis. This syndrome, also called Mollaret's syndrome, causes multiple mild cases of meningitis. Examining a sample of spinal fluid shows white blood cells called lymphocytes, and no microorganisms grow if the fluid is cultured.

Researchers have recently shown that a herpes virus is responsible for most cases of Mollaret's syndrome, and I would be curious to know if you have ever been diagnosed with a herpes infection. Experts have long known that people having their first episode of genital herpes may also get meningitis. A laboratory test called PCR (polymerase chain reaction) may show the herpes virus in the spinal fluid of patients with recurrent meningitis. Also, some people have minor genital lesions (blisters and ulcers) at the same time as the meningitis. The good news is that each episode of meningitis is likely to be harmless.

The diagnosis of the syndrome is now rather easy. During an episode of meningitis, a doctor sends a sample of spinal fluid for a PCR test to look for the herpes simplex viruses. Treatment, however, is not so simple. If you test positive for herpes, then treating that episode of meningitis with the drug used to treat herpes infections -- acyclovir (trade name Zovirax) -- probably helps only minimally. Perhaps of more benefit would be preventive treatment. If you continue to have recurrences, your doctor may want to consider giving you continuous treatment with acyclovir in an attempt to eliminate your problem.

If you do not have any more recurrences, there is no real way to prove the diagnosis. You could have an antibody test for the herpes simplex viruses, but many people have positive results on this test without having any manifestations of disease.