Definition Bacterial (back-tier-ee-al) meningitis (men-in-jie-tis) is an infection of the membranes that cover the brain.
What is going on in the body? There are a number of different organisms that can cause bacterial meningitis. Also, newborns can develop meningitis from bacteria that they come in contact with during delivery. Meningitis causing bacteria generally begin growing in a person's nose and throat. If not stopped by the immune system, the bacteria go on to invade the body. At that point, the bacteria can enter the blood stream and travel to the central nervous system. The infection then settles in the fluid and the membranes around the brain. The resulting inflammation is responsible for many of the signs and symptoms of meningitis. It is also thought to play a role in some of the complications of meningitis.
What are the signs and symptoms of the infection? Symptoms of bacterial meningitis include:
seizure, or convulsion, or other neurological problems
What are the causes and risks of the infection? Risk factors for bacterial meningitis include:
compromised immune system which is the body's defence system
lack of immunity to or recent infection with meningitis-causing bacteria
exposure to a person with a bacterial infection from meningitis-causing organisms
skull fracture or a malformed skull
What can be done to prevent the infection? Immunisation with Haemophilus (he-ma-fah-les) influenza (in-flew-en-zah) type b vaccine is very effective in preventing this disease. This series of Injections is recommended for all children. It is one of the recommended immunisations given to babies. Due to this vaccine, this once common cause of meningitis is now almost nonexistent. Vaccines exist for other meningitis-causing organisms such as, Streptococcus (strep-tah-kok-us) pneumoniae (new-moe-nee). Use of these vaccines is recommended in special cases. Preventive treatment with antibiotics is often used as well as use of antibiotics after exposure to many of these bacteria.
How is the infection diagnosed? Meningitis is diagnosed by looking at the cerebral spinal fluid, the clear fluid surrounding the brain and spinal cord. This is obtained from a lumbar puncture or spinal tap. White blood cells, irregular protein and blood sugar levels, and bacteria in the fluid are signs of infection. Bacteria can often be cultured or grown in the laboratory from a sample of the fluid. This shows which germ is causing the infection. Chemical signs of the bacteria, called an antigen, can be helpful in cases in which the culture does not work.
What are the long-term effects of the infection? Bacterial meningitis can sometimes be fatal. Other long-term effects include:
What are the risks to others? People who are infected with any of the meningitis bacteria can potentially pass it to others.
What are the treatments for the infection? There are a number of treatments for the disease:
Treatment should commence before a laboratory diagnosis is made
Antibiotics, such as penicillin, cefotaxime, or ceftriaxone, injected into a vein are the most important treatment.
Corticosteroids, such as methylprednisolone or prednisone (powerful anti-inflammatory drugs), are sometimes used with certain types of infection. These drugs decrease swelling in an attempt to prevent complications.
Medication or artificial breathing machines are used if increased pressure in the head occurs after infection.
Rarely, surgery is performed if an abscess, or collection of pus, develops.
What are the side effects of the treatments? Side effects vary depending on the type of treatment needed.
Author: Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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