Bacterial meningitis is not solely a childhood disease, but a disproportionate number of its victims are infants and children. The symptoms and the speed of their onset can strike terror in the heart of a parent.

It may happen something like this: A child may have been suffering from a cold or a sore throat or, perhaps, nothing at all. Suddenly, the youngster is irritable, running a high fever, complaining of headache, and vomiting. Infants develop an eerie, high-pitched cry. Muscles in the neck and elsewhere may stiffen. The child may become delirious, slip into a coma, or have convulsions.

An alarmed parent's first impulse under these circumstances is to seek emergency medical care. It is precisely the right response. Without treatment, the disease may be lethal, and the danger increases with youth; a very young child could die within hours of the time the first signs of illness appear. Whenever meningitis is suspected — in a child or adult — the patient should be rushed to the nearest hospital.

Before the advent of antibiotics, the vast majority of bacterial meningitis cases, in those of all ages, proved fatal. Now, with prompt diagnosis and treatment, more than 90 percent survive; among those who receive timely medical care, the relatively few fatalities now occur mostly among the extremely young and the extremely old.

Multiple Causes

Meningitis is an inflammation of the meninges, the membranes surrounding the brain and spinal cord. Sometimes, perhaps even most of the time, the infectious agent is a virus. Those cases, however, are cause for far less concern than the ones resulting from bacterial infection.

"There are probably more cases of viral meningitis than bacterial," says Susan Alpert, M.D., a pediatric infectious disease specialist in the division of anti-infective drug products at FDA's Center for Drug Evaluation and Research. "But it can be so mild that the patient doesn't even see a physician, and many cases are never diagnosed. Bacterial meningitis is such a serious infection that it invariably comes to medical attention."

That serious infection may be caused by any of a number of bacteria (see "Bacterial Bad Guys"). Many people would assume, from its name, that the bacterium called Neisseria meningitidis (also known as meningococcus) is the major cause of the disease. In fact, it ranks second to another organism. The leading cause of bacterial meningitis is actually a strain, type b, of the confusingly named Haemophilus influenzae, so called because, when it was first identified, it was erroneously believed to be the cause of influenza or "flu" (which is actually caused by a virus). These two bacteria, together with the pneumococcus Streptococcus pneumoniae, account for four out of five cases of bacterial meningitis.

Diagnosis and Treatment

Hospital diagnosis of bacterial meningitis begins with a lumbar puncture ("spinal tap") to obtain a sample of the cerebrospinal fluid that bathes the brain and flows down through the spinal canal. Normally clear, the fluid is analyzed for the presence of bacteria and other evidence of infection. Samples of blood, urine, and respiratory secretions may also be taken. But since the disease can progress so quickly, treatment — with intravenous antibiotics — is started even before any test results are available.

Among those drugs currently widely used to treat bacterial meningitis are a class of antibiotics called cephalosporins, especially cefotaxime (Claforan) and ceftriaxone (Rocephin), and various members of the penicillin family. At least a week of treatment, and sometimes more, is needed.

When H. influenzae type b or meningococcal meningitis has been diagnosed, household members and other close contacts may be placed on a short course of prophylaxis (prevention) with the antibiotic rifampin (Rifadin, Rimactane).

The dread of bacterial meningitis, whatever the cause, is based not only on its reputation as a killer but on the possibility of neurological complications — lingering deficits that can be especially devastating in infants and children, who are still growing and developing. Those complications may include persistent hearing loss, mental retardation, and recurrent convulsions, and they occur in 20 to 30 percent of those who survive a bout of bacterial meningitis.

An additional type of therapy has been proposed for children with bacterial meningitis, based on the possibility of staving off one of these neurological aftereffects. One group of researchers has suggested that adding dexamethasone, a corticosteroid hormone, to the antibiotic treatment may help prevent subsequent deafness.

"There have been numerous discussions of this question," says Susan Alpert, "and there are people on both sides. The original reports came from just one medical center. Right now, there are studies being conducted around the country."

Why not just add the drug, in case it might help? As Alpert points out, "No therapy is totally benign." Corticosteroids can also have adverse side effects. And most of the children in the reported studies had Hib infection and were treated with one of two antibiotics; the outcome might be different with different bacteria and/or different antibiotics.

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