What is meningitis?
Meningitis is an infection of the tissues (meninges) and sometimes the fluid (cerebral spinal fluid, or CSF) that surrounds the brain and spinal cord. Meningitis results in swelling of the brain tissue and in some cases the spinal tissue (spinal meningitis). When brain tissue swells, less blood and oxygen reach brain cells.
Meningitis is a potentially fatal inflammation of the meninges, the thin, membranous covering of the brain and the spinal cord. Meningitis is most commonly caused by infection (by bacteria, viruses, or fungi), although it can also be caused by bleeding into the meninges, cancer, diseases of the immune system, and an inflammatory response to certain types of chemotherapy or other chemical agents. The most serious and difficult-to-treat types of meningitis tend to be those caused by bacteria. The infection occurs most often in infants, young adults between the ages of 15 and 24, older adults, and people who have a long-standing health condition, such as a weakened immune system.
Major bacteria that cause meningitis are Streptococcus pneumoniae, Haemophilus influenzae, staphylococcus and meningococcus. Meningitis caused by Haemophilus influenzae is known to occur in outbreaks, examples include outbreaks in dorms and military outbreaks. Community acquired cases of meningitis are usually caused by Streptococcus pneumoniae, seen in elderly patients. Listeria monocytogenes and Neisseria meningitis are also other causes of community acquired meningitis. On the other hand, viruses are the most common cause of aseptic meningitis.
Meningitis can range from mild to life-threatening. The severity usually depends on the organism causing the infection and a person's age and overall health.
More information on meningitis
What is meningitis? - Meningitis is an inflammation of the meninges, the membrane envelopes that encase the brain and spinal cord. Meningitis can range from mild to life-threatening.
What's viral meningitis? - Viral meningitis, also called aseptic meningitis, is caused by many different viruses. Most viral meningitis is associated with enteroviruses.
What is bacterial meningitis? - Bacterial meningitis may be fatal or cause serious long-term complications. Acute bacterial meningitis is a true medical emergency.
What causes meningitis? - The most common infectious causes of meningitis vary according to an individual's age, habits, living environment, and health status.
What causes bacterial meningitis? - A number of types of bacteria can cause acute bacterial meningitis. They include pneumococcus, meningococcus, haemophilus, and listeria.
What're the risk factors for meningitis? - People who work with domestic animals and pregnant women are at increased risk for meningitis associated with listeriosis.
What're the complications of meningitis? - The complications of meningitis can be severe. Some of these effects are permanent and physically disabling.
How is meningitis diagnosed? - A number of techniques are used to verify the diagnosis. The most important test used to diagnose meningitis is the lumbar puncture.
What's the treatment for meningitis? - Antibiotic medications are the most important element of treatment against bacterial agents of meningitis.
How to prevent meningitis? - Vaccines to protect against S. pneumoniae and H. influenzae type b (Hib) are available and have dramatically reduced the number of meningitis cases.