Definition of Meningococcal meningitis

Meningococcal meningitis: Inflammation of the meninges (the membranes covering of the brain and spinal cord) due to infection with the meningococcus bacterium Neisseria meningitidis.

Meningococcal meningitis typically starts like the flu with the sudden onset of an intense headache, fever, sore throat, nausea, vomiting and malaise. But, unlike the flu, a stiff neck and intolerance of lights are frequent symptoms. Within hours of the first symptoms the disease can progress to delirium, coma or convulsions and invade the bloodstream, setting off a bodywide infection that attacks organs and can cause circulatory collapse, a hemorrhagic rash and gangrene.

At the first suspicion of meningococcal meningitis, the case must be treated as a medical emergency. The diagnosis is made by examining the fluid obtained through a spinal tap. A crucial step is to identify the particular serotype of the causative bacterium and its susceptibility to antibiotics.

The disease is highly contagious. It can be spread by a cough or sneeze, a kiss or even a drink from a contaminated cup. It has a high fatality rate -- up to 15% with treatment and as much as 50% without treatment. And a disproportionate number of victims are children or young adults, with the greatest number being college freshmen who live in dormitories. The peak incidence of the disease in North America is from November to March.

The more common serotypes in teenagers and young adults are A and C. The available vaccine protects against these and against types Y and W135. There is no vaccine for Type B, which more often afflicts young children.

A federal health advisory panel in the U.S. recommends that college freshmen be informed about the disease and about the availability of the vaccine, which is effective against most of the strains that infect college students. The vaccine takes effect within a week or two.

Treatment is with antibiotics, usually in a hospital setting. Prevention is by improved hygiene and vaccination of particularly susceptible persons.