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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

Fluids for people with acute bacterial meningitis

Bacterial meningitis is an infection of the fluid in the spinal cord and surrounding the brain. Antibiotics are prescribed as treatment. Supportive care includes other drugs and the regulation of fluid intake. There has been disagreement about whether fluids should be restricted or unrestricted as there are potential risks from giving too much fluid (brain swelling) as well as too little fluid (shock).

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.

Osmotic therapies added to antibiotics for acute bacterial meningitis

Meningitis is a condition where bacteria, fungi or viruses spread from the blood and infect the membranes and fluid that surround the brain and spinal cord. All types of meningitis are very serious but acute bacterial meningitis has a rapid onset and is usually fatal within hours to days without treatment. Signs and symptoms usually include high fever, severe headache, convulsions, coma and mental confusion. Even with antibiotics the mortality rate is 10% to 15% in children with bacterial meningitis and 20% to 30% in adults in high‐income countries, rising to 50% in adults in low‐income countries. Increased swelling of the brain caused by the infection is thought to contribute to death and may lead to complications in survivors such as long‐term brain damage, deafness, epilepsy and learning difficulties in children. Bacterial meningitis is relatively rare in well‐resourced settings but is more common in low‐income countries, particularly where the prevalence of HIV is high.

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Summaries for consumers

Fluids for people with acute bacterial meningitis

Bacterial meningitis is an infection of the fluid in the spinal cord and surrounding the brain. Antibiotics are prescribed as treatment. Supportive care includes other drugs and the regulation of fluid intake. There has been disagreement about whether fluids should be restricted or unrestricted as there are potential risks from giving too much fluid (brain swelling) as well as too little fluid (shock).

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.

Osmotic therapies added to antibiotics for acute bacterial meningitis

Meningitis is a condition where bacteria, fungi or viruses spread from the blood and infect the membranes and fluid that surround the brain and spinal cord. All types of meningitis are very serious but acute bacterial meningitis has a rapid onset and is usually fatal within hours to days without treatment. Signs and symptoms usually include high fever, severe headache, convulsions, coma and mental confusion. Even with antibiotics the mortality rate is 10% to 15% in children with bacterial meningitis and 20% to 30% in adults in high‐income countries, rising to 50% in adults in low‐income countries. Increased swelling of the brain caused by the infection is thought to contribute to death and may lead to complications in survivors such as long‐term brain damage, deafness, epilepsy and learning difficulties in children. Bacterial meningitis is relatively rare in well‐resourced settings but is more common in low‐income countries, particularly where the prevalence of HIV is high.

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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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