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Bacterial Meningitis

Inflammation of the membranes surrounding the brain and spinal cord due to a bacterial infection.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

About Bacterial Meningitis

Bacterial meningitis is a rare but potentially fatal disease. It can be caused by several types of bacteria that first cause an upper respiratory tract infection and then travel through the blood stream to the brain. The disease can also occur when certain bacteria invade the meninges directly. The disease can cause stroke, hearing loss, and permanent brain damage.

Pneumococcal meningitis is the most common form of meningitis and is the most serious form of bacterial meningitis. Some 6,000 cases of pneumococcal meningitis are reported in the United States each year. The disease is caused by the bacterium Streptococcus pneumoniae, which also causes pneumonia, blood poisoning (septicemia), and ear and sinus infections. At particular risk are children under age 2 and adults with a weakened or depressed immune system, including the elderly. Persons who have had pneumococcal meningitis often suffer neurological damage ranging from deafness to severe brain damage. There are immunizations available for certain strains of the Pneumococcal bacteria....Read more about Bacterial Meningitis NIH - National Institute of Neurological Disorders and Stroke

What works? Research summarized

Evidence reviews

Systematic review of dexamethasone as an adjuvant therapy for bacterial meningitis in children

Bibliographic details: Prats JA, Gaspar AJ, Ribeiro AB, De Paula GD, de S.P.V. Boas LV, de Sa FP.  Systematic review of dexamethasone as an adjuvant therapy for bacterial meningitis in children. Revista Paulista de Pediatria 2012; 30(4): 586-593

Does this child have bacterial meningitis? A systematic review of clinical prediction rules for children with suspected bacterial meningitis

BACKGROUND: Acute meningitis is a relatively common phenomenon in children. Identifying which children are most likely to have bacterial meningitis vs. self-limiting aseptic meningitis is important, as these children require investigation and antibiotic treatment.

Diagnostic accuracy of cerebrospinal fluid lactate for differentiating bacterial meningitis from aseptic meningitis: a meta-analysis

This review concluded that cerebrospinal fluid lactate may be useful for ruling out bacterial meningitis, but pre-treatment with antibiotics reduced its clinical accuracy. This conclusion reflects the data presented, but should be interpreted cautiously given some limitations in the search strategy and reporting of the review.

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Summaries for consumers

Newer, third generation cephalosporins versus conventional antibiotics for treating acute bacterial meningitis

Acute bacterial meningitis is a life‐threatening illness. Currently the evidence suggests that old and new antibiotics offer the same level of treatment. Bacteria which cause meningitis are often thought to be resistant to conventional (older) antibiotics, and so doctors often prescribe newer antibiotics (called third generation cephalosporins). Commencing treatment early is vitally important and the choice of antibiotic is often made without any knowledge of possible drug resistance. This review examined 19 studies with 1496 participants to see whether there is a difference in effectiveness between conventional and newer antibiotics. This review found no differences. Adverse effects in both approaches were similar, except for diarrhoea, which was more common in the cephalosporin group. Only three studies dealt with adults; the remaining studies recruited participants aged 15 years and younger. Therefore, we believe that the results probably pertain more to children. Conventional and newer antibiotics seem reasonable options for initial, immediate treatment. The choice may depend on availability, affordability and local policies.

Intraventricular antibiotics for bacterial meningitis in neonates

Infection of the membranes and the fluid surrounding the brain (meningitis) and of the fluid‐filled spaces in the brain (ventriculitis) may be caused by bacteria, especially gram‐negative bacteria. This type of infection is difficult to eradicate using safe doses of antibiotics given into the blood stream. In theory, intraventricular administration of antibiotics (administration of antibiotics into the fluid‐filled spaces in the centre of the brain) would produce higher antibiotic concentrations in the fluid in the brain than intravenous administration alone, and eliminate the bacteria more quickly. However, taps of the fluid‐filled spaces may cause harm as the needle has to penetrate the brain tissue. Only one trial was identified. In this trial enrolling infants with gram‐negative meningitis and ventriculitis, the use of intraventricular antibiotics in addition to intravenous antibiotics resulted in a three‐fold increased risk for mortality compared to standard treatment with intravenous antibiotics alone. Based on this result, intraventricular antibiotics should be avoided. Further trials comparing these interventions are not justified in newborn infants.

Corticosteroids for bacterial meningitis

Acute bacterial meningitis is an infection of the meninges (the system of membranes which envelops the brain and spinal cord) that often causes hearing loss. Bacterial meningitis is fatal in 5% to 40% of children and 20% to 50% of adults despite treatment with adequate antibiotics. It is caused by bacteria that usually spread from an ear or respiratory infection and is treated with antibiotics. Corticosteroids are drugs that can reduce the inflammation caused by infection. This inflammation has been shown to aggravate damage to the nervous system in experimental meningitis studies in animals. Research on the use of corticosteroids in addition to antibiotics has had conflicting results. This review of 25 trials, including 4121 participants, found that the corticosteroid dexamethasone leads to a reduction in hearing loss and other neurological sequelae in participants in high‐income countries who have bacterial meningitis, but is not effective in low‐income countries. An analysis for different bacteria causing meningitis showed that patients with meningitis due to Streptococcus pneumoniae (S. pneumoniae) treated with corticosteroids had a lower death rate, while no effect on mortality was seen in patients with Haemophilus influenzae (H. influenzae) and Neisseria meningitidis (N. meningitidis) meningitis. Corticosteroids decreased the rate of hearing loss in children with meningitis due to H. influenzae, but not in children with meningitis due to other bacteria. Dexamethasone increased the rate of recurrent fever but was not associated with other adverse events.

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Terms to know

Bacterial Infections
An acute infectious disorder caused by gram-positive or gram-negative bacteria.
Brain
The part of the central nervous system that is contained within the skull (cranium).
Inflammation
Redness, swelling, pain, and/or a feeling of heat in an area of the body. This is a protective reaction to injury, disease, or irritation of the tissues.
Meninges
The three thin layers of tissue that cover and protect the brain and spinal cord.
Neurological
Having to do with nerves or the nervous system.
Neurologist
A doctor who specializes in the diagnosis and treatment of disorders of the nervous system.
Spinal Cord
A column of nerve tissue that runs from the base of the skull down the back. It is surrounded by three protective membranes, and is enclosed within the vertebrae (back bones). The spinal cord and the brain make up the central nervous system, and spinal cord nerves carry most messages between the brain and the rest of the body.
Viral Infections
A general term for diseases produced by viruses.

More about Bacterial Meningitis

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See Also: Viral Meningitis

Other terms to know: See all 8
Bacterial Infections, Brain, Inflammation

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