Meningococcal
Disease What
is meningitis? Meningitis
is an infection of the fluid of a person's spinal cord and the fluid that surrounds
the brain. People sometimes refer to it as spinal meningitis. Meningitis is usually
caused by a viral or bacterial infection. Knowing whether meningitis is caused
by a virus or bacterium is important because the severity of illness and the treatment
differ. Viral meningitis is generally less severe and resolves without specific
treatment, while bacterial meningitis can be quite severe and may result in brain
damage, hearing loss, or learning disability. For bacterial meningitis, it is
also important to know which type of bacteria is causing the meningitis because
antibiotics can prevent some types from spreading and infecting other people.
Before the 1990s, Haemophilus influenzae type b (Hib) was the leading cause
of bacterial meningitis, but new vaccines being given to all children as part
of their routine immunizations have reduced the occurrence of invasive disease
due to H. influenzae. Today, Streptococcus pneumoniae and Neisseria
meningitidis are the leading causes of bacterial meningitis. What
are the signs and symptoms of meningitis? High
fever, headache, and stiff neck are common symptoms of meningitis in anyone over
the age of 2 years. These symptoms can develop over several hours, or they may
take 1 to 2 days. Other symptoms may include nausea, vomiting, discomfort looking
into bright lights, confusion, and sleepiness. In newborns and small infants,
the classic symptoms of fever, headache, and neck stiffness may be absent or difficult
to detect, and the infant may only appear slow or inactive, or be irritable, have
vomiting, or be feeding poorly. As the disease progresses, patients of any age
may have seizures. How
is meningitis diagnosed? Early
diagnosis and treatment are very important. If symptoms occur, the patient should
see a doctor immediately. The diagnosis is usually made by growing bacteria from
a sample of spinal fluid. The spinal fluid is obtained by performing a spinal
tap, in which a needle is inserted into an area in the lower back where fluid
in the spinal canal is readily accessible. Identification of the type of bacteria
responsible is important for selection of correct antibiotics. Can
meningitis be treated? Bacterial
meningitis can be treated with a number of effective antibiotics. It is important,
however, that treatment be started early in the course of the disease. Appropriate
antibiotic treatment of most common types of bacterial meningitis should reduce
the risk of dying from meningitis to below 15%, although the risk is higher among
the elderly. Is
meningitis contagious? Yes,
some forms of bacterial meningitis are contagious. The bacteria are spread through
the exchange of respiratory and throat secretions (i.e., coughing, kissing). Fortunately,
none of the bacteria that cause meningitis are as contagious as things like the
common cold or the flu, and they are not spread by casual contact or by simply
breathing the air where a person with meningitis has been. However,
sometimes the bacteria that cause meningitis have spread to other people who have
had close or prolonged contact with a patient with meningitis caused by Neisseria
meningitidis (also called meningococcal meningitis) or Hib. People in the
same household or day-care center, or anyone with direct contact with a patient's
oral secretions (such as a boyfriend or girlfriend) would be considered at increased
risk of acquiring the infection. People who qualify as close contacts of a person
with meningitis caused by N. meningitidis should receive antibiotics
to prevent them from getting the disease. Antibiotics for contacts of a person
with Hib meningitis disease are no longer recommended if all contacts 4 years
of age or younger are fully vaccinated against Hib disease (see below). Are
there vaccines against meningitis? Yes,
there are vaccines against Hib, against some serogroups of N. meningitidis
and many types of Streptococcus pneumoniae. The vaccines against Hib are
very safe and highly effective. There
are two vaccines against N. meningitidis available in the U.S. Meningococcal
polysaccharide vaccine (MPSV4 or Menomune®) has been approved by the
Food and Drug Administration (FDA) and available since 1981. Meningococcal conjugate
vaccine (MCV4 or MenactraT) was licensed in 2005. Both vaccines can prevent 4
types of meningococcal disease, including 2 of the 3 types most common in the
U.S. (serogroup C, Y, and W-135) and a type that causes epidemics in Africa (serogroup
A). Meningococcal vaccines cannot prevent all types of the disease. But they do
protect many people who might become sick if they didn't get the vaccine. Meningitis
cases should be reported to state or local health departments to assure follow-up
of close contacts and recognize outbreaks. MCV4
is recommended for all children at their routine preadolescent visit (11 to 12
years of age). For those who have never gotten MCV4 previously, a dose is recommended
at high school entry. Other adolescents who want to decrease their risk of meningococcal
disease can also get the vaccine. Other people at increased risk for whom routine
vaccination is recommended are college freshmen living in dormitories, microbiologists
who are routinely exposed to meningococcal bacteria, U.S. military recruits, anyone
who has a damaged spleen or whose spleen has been removed; anyone who has terminal
complement component deficiency (an immune system disorder), anyone who is traveling
to the countries which have an outbreak of meningococcal disease, and those who
might have been exposed to meningitis during an outbreak. MCV4 is the preferred
vaccine for people 11 to 55 years of age in these risk groups, but MPSV4 can be
used if MCV4 is not available. MPSV4 should be used for children 2 to 10 years
old, and adults over 55, who are at risk. Although
large epidemics of meningococcal meningitis do not occur in the United States,
some countries experience large, periodic epidemics. Overseas travelers should
check to see if meningococcal vaccine is recommended for their destination. Travelers
should receive the vaccine at least 1 week before departure, if possible. Information
on areas for which meningococcal vaccine is recommended can be obtained by calling
the Centers for Disease Control and Prevention at (404)-332-4565. There
are vaccines to prevent meningitis due to S. pneumoniae (also called
pneumococcal meningitis) which can also prevent other forms of infection due to
S. pneumoniae. The pneumococcal polysaccharide vaccine is recommended
for all persons over 65 years of age and younger persons at least 2 years old
with certain chronic medical problems. There is a newly licensed vaccine (pneumococcal
conjugate vaccine) that appears to be effective in infants for the prevention
of pneumococcal infections and is routinely recommended for all children greater
than 2 years of age. Centers
for Disease Control and Prevention
http://www.cdc.gov/ |
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