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Inflammation of the meninges (three thin layers of tissue that cover and protect the brain and spinal cord). Meningitis is usually caused by a bacterial or viral infection, but sometimes is caused by cancer, drug allergies, or inflammatory diseases.

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(Source: NIH - National Cancer Institute)

About Meningitis

Meningitis is most often caused by a bacterial infection. It also may be caused by a virus, fungal infection, parasite, a reaction to certain medications or medical treatments, a rheumatologic disease such as lupus, some types of cancer, or a traumatic injury to the head or spine.

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....Read more about 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

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.

Adenosine deaminase and tuberculous meningitis: a systematic review with meta-analysis

This review found that adenosine deaminase cannot distinguish between bacterial meningitis and tuberculous meningitis, but ranges of adenosine deaminase values could improve tuberculous meningitis diagnosis after bacterial meningitis has been ruled out. These conclusions should be interpreted with some caution due to the possibility of missing studies, unclear study quality and heterogeneity between studies.

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Summaries for consumers

Corticosteroids for managing tuberculous meningitis

Tuberculous meningitis is a serious form of tuberculosis affecting the meninges covering the brain and spinal cord. The clinical outcome is poor even when treated with conventional antituberculous drugs. Corticosteroids are commonly used in addition to antituberculous drugs for treating the condition. They help reduce swelling and congestion of the meninges, and thus decrease pressure inside the brain and the attendant risk of death or disabling residual neurological deficit among survivors. This review identified seven trials involving 1140 people that evaluated either dexamethasone or prednisolone given in addition to antituberculous drugs; only one trial was of high quality. Overall, the trials showed that corticosteroids help reduce the risk of death or a risk of death or disabling residual neurological deficit. Only one trial evaluated the effects of corticosteroids in HIV‐positive people, but the effects were unclear. Given the results of the review, all HIV‐negative people with tuberculous meningitis should receive corticosteroids, but more trials are needed in HIV‐positive people.

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.

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Terms to know

Bacterial Meningitis
Inflammation of the membranes surrounding the brain and spinal cord due to a bacterial infection.
The part of the central nervous system that is contained within the skull (cranium).
Inflammation of the brain.
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.
The three thin layers of tissue that cover and protect the brain and spinal cord.
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 Meningitis
Inflammation of the membranes surrounding the brain and spinal cord due to a viral infection.

More about Meningitis

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Other terms to know: See all 7
Bacterial Meningitis, Brain, Encephalitis

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