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Meningitis

Meningitis is swelling and irritation (inflammation) of the membranes covering the brain and spinal cord. This inflammation causes changes in the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord.

See also:

Causes

The most common causes of meningitis are viral infections that usually get better without treatment. However, bacterial meningitis infections are extremely serious, and may result in death or brain damage even if treated.

Meningitis is also caused by:

Types include:

Acute bacterial meningitis is a true medical emergency, and requires immediate treatment in a hospital.

Viral meningitis is milder and occurs more often than bacterial meningitis. It usually develops in the late summer and early fall, and often affects children and adults under age 30. Most infections occur in children under the age of 5. Most viral meningitis is due to enteroviruses, which are viruses that also cause intestinal illness.

Many other types of viruses can cause meningitis. For example, viral meningitis can be caused by herpes viruses, the same virus that can cause cold sores and genital herpes (although people with cold sores or genital herpes are not at a greater risk of developing herpes meningitis).

Recently, West Nile virus, spread by mosquito bites, has become a cause of viral meningitis in most of the United States.

Symptoms

Other symptoms that can occur with this disease:

Meningitis is an important cause of fever in newborn children.

Exams and Tests

Treatment

Doctors prescribe antibiotics for bacterial meningitis. The type will vary depending on the bacteria causing the infection. Antibiotics are not effective in viral meningitis.

Other medications and intravenous fluids will be used to treat symptoms such as brain swelling, shock, and seizures. Some people may need to stay in the hospital, depending on the severity of the illness and the treatment needed.

Outlook (Prognosis)

Early diagnosis and treatment of bacterial meningitis is essential to prevent permanent neurological damage. Viral meningitis is usually not serious, and symptoms should disappear within 2 weeks with no lasting complications.

Possible Complications

When to Contact a Medical Professional

If you feel that you or your child has symptoms of meningitis, get emergency medical help immediately. Early treatment is key to a good outcome.

Prevention

The meningococcal vaccination is recommended for:

Some communities conduct vaccination campaigns after an outbreak of meningococcal meningitis.

References

Swartz MN. Meningitis: bacterial, viral, and other. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 437.

Update Date: 9/28/2008

Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PhD, MD, Instructor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.


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