Webster's New World Medical Dictionary

meningitis, infectious
Inflammation of the
meninges due to bacterial, viral, or protozoan infec-
tion. Most of the agents known to cause meningitis
are infectious, but very few people exposed to them
develop meningitis. Those at greatest risk for infec-
tious meningitis include people with AIDS, infants,
transplant patients, and others whose immune sys-
tems may be compromised. For this reason, infec-
tious meningitis patients are almost always isolated
until the risk of spreading the illness to others has
passed.
meningitis, Kernig sign of
See 
Kernig sign.
meningitis, meningococcal
Inflammation of
the meninges due to infection with the 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 with the flu, a stiff
neck and intolerance of lights are frequent symp-
toms of meningococcal meningitis. 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. Meningococcal
meningitis is a medical emergency. Diagnosis is
made through examination of the CSF obtained via
lumbar puncture. Treatment includes use of appro-
priate antibiotics, usually in the hospital. The dis-
ease is highly contagious; it is spread by contact
with an affected individual’s respiratory secretions,
such as by coughing or kissing. Meningococcal
meningitis has a high fatality rate if not recognized
and treated properly. Vaccines against four types of
meningococcal disease are available and are rec-
ommended for at-risk persons, including college
freshmen living in dormitories.