What Is Bacterial 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 (
viral meningitis) or bacterial infection (bacterial meningitis). Knowing whether it 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.
Bacterial meningitis is a medical emergency -- immediate medical attention is required. Left untreated, the condition has a high death rate.
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.
Common symptoms in anyone over the age of two years include:
These symptoms can develop over several hours, or they may take one to two days.
Other symptoms of bacterial
meningitis may include:
- Nausea
- Vomiting
- Discomfort when looking into bright lights
- Confusion
- Sleepiness.
In newborns and small infants, the classic bacterial
meningitis symptoms of fever,
headache, and neck stiffness may be absent or difficult to detect. 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.
Early diagnosis and treatment of bacterial meningitis are very important. If symptoms occur, the patient should see a doctor immediately.
The diagnosis of bacterial meningitis 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 for bacterial meningitis is important for selection of correct antibiotics.
Treating Bacterial Meningitis
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 percent, although the risk is higher among the elderly.
Some forms of bacterial
meningitis are contagious. The bacteria are spread through the exchange of respiratory and throat secretions (e.g., coughing, kissing).
Fortunately, none of the bacteria that cause bacterial 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 bacterial 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 (such as a boyfriend or girlfriend) who has direct contact with a patient's oral secretions would be considered at increased risk of acquiring bacterial meningitis.
People who qualify as close contacts of a person with meningitis caused by N. meningitidis should receive antibiotics to prevent them from getting bacterial meningitis. Antibiotics for contacts of a person with Hib meningitis disease are no longer recommended if all contacts four years of age or younger are fully vaccinated against Hib disease.
Vaccines for Bacterial Meningitis
There are vaccines against Hib, some serogroups of N. meningitidis, and many types of Streptococcus pneumoniae. The vaccines against Hib are very safe and highly effective.
