Meningitis
- Reviewed by Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
What is it?
Meningitis is an inflammation of coverings (meninges) of the brain and spinal cord. Most often it is caused by a viral or bacterial infection. Other infectious agents such as fungi can also cause meningitis. Rarer causes of meningitis include atypical drug reactions and systemic lupus erythematosus.
Anyone can get viral meningitis, but it occurs more often in children. While many different viruses can cause meningitis, an enterovirus tends to be the usual culprit.
Viral meningitis due to enterovirus peaks in mid-summer through early autumn. But it can occur any time of the year. Except for the rare case of herpes meningitis, viral meningitis will resolve on its own after seven to 10 days.
Bacterial meningitis, formerly called spinal meningitis, is a very serious and potentially fatal infection. It can strike very healthy people, but infants and older people are more susceptible. In the past, the three most common types of bacterial meningitis were caused by Neisseria meningitidis, Haemophilus influenza and Streptococcus pneumoniae. Now that we have very effective vaccines to help prevent all three types, bacterial meningitis in otherwise healthy children and adults occurs less often.
Besides infants and the elderly, people with chronic diseases and/or impaired immune systems have the greatest risk of meningitis caused by bacteria and fungi.
Symptoms
The symptoms of meningitis vary, but often include
- headache
- fever
- stiff neck.
Other symptoms may include
- sensitivity to light
- nausea
- vomiting
- drowsiness
- confusion.
Symptoms may be milder in cases of viral meningitis, while in cases of bacterial meningitis, symptoms may come on quite suddenly. In very young children, symptoms may be particularly hard to detect. Babies with meningitis may be less active, vomit, refuse to eat, or be irritable. A person in later stages of bacterial meningitis may have seizures and lose consciousness (pass out).
Diagnosis
Meningitis is diagnosed by testing some of the fluid that surrounds the spinal cord for disease-causing bacteria or infection-fighting cells. The fluid is removed from the spinal cord with a needle in a procedure known as a spinal tap or lumbar puncture.
Expected duration
Viral meningitis tends to get better on its own in seven to 10 days. In contrast, if bacterial meningitis is not diagnosed and treated early, it can cause permanent disability or death. The length of time that medication is needed for bacterial meningitis depends on the person's age, response to the medication, and other factors.
Prevention
The bacteria and viruses that cause meningitis are found in bodily fluids, such as saliva and mucus, and are spread by direct contact. Some people carry the germs in their nose and throat and can pass them on to other people, even though these "carriers" are not sick. If you are in close contact with someone who has been diagnosed with bacterial meningitis, you may be given antibiotics to prevent you from getting the disease.
Vaccination against Streptococcus pneumoniae (pneumonia shot), Haemophilus influenzae and Neisseria meningitidis is the best way to prevent bacterial meningitis.
There is no vaccine to prevent the common types of viral meningitis.
Treatment
Viral meningitis is treated much like the flu, with rest and plenty of fluids, and you should recover in a week to 10 days. Bacterial meningitis is a medical emergency. It requires high-dose intravenous antibiotics in a hospital setting. Depending upon the patient and suspected type of bacterial meningitis, intravenous dexamethasone, a corticosteroid, may be given at the time of diagnosis.
When to call a professional
If you or your child is exhibiting symptoms of meningitis, contact your doctor immediately.
Prognosis
For most people with viral meningitis, the outlook is excellent.
The prognosis for bacterial meningitis depends on the person's age, which bacterium is causing the disease, and how early the disease was diagnosed.
Additional info
Centers for Disease Control and Prevention (CDC)
https://www.cdc.gov/
About the Reviewer
Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
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