Meningitis is an infection that causes inflammation of the membranes covering the brain and spinal cord. Non-bacterial meningitis is often referred to as "aseptic meningitis."
The most common causes of meningitis are viral infections that usually resolve without treatment. However, bacterial infections of the meninges are extremely serious illnesses, and may result in death or brain damage even if treated.
Meningitis is also caused by fungi, chemical irritation, drug allergies, and tumors.
- Bacterial meningitis is most commonly caused by one of three types of bacteria: Haemophilus influenzae type b, Neisseria meningitidis, and Streptococcus pneumoniae bacteria.
- The bacteria are spread by direct close contact with the discharges from the nose or throat of an infected person.
- Bacterial meningitis can be treated with antibiotics.
- Prevention depends on use of vaccines, rapid diagnosis, and prompt treatment of close personal contacts.
Bacterial meningitis is a serious infection of the fluid in the spinal cord and the fluid that surrounds the brain.
What is bacterial meningitis?
Meningitis is an infection of the fluid in the spinal cord and the fluid that surrounds the brain. Meningitis is usually caused by an infection with a virus or a bacterium. Knowing whether meningitis is caused by a virus or a bacterium is important because of differences in the seriousness of the illness and the treatment needed.
VIRAL MENINGITIS is usually relatively mild. It clears up within a week or two without specific treatment. Viral meningitis is also called aseptic meningitis.
BACTERIAL MENINGITIS is much more serious. It can cause severe disease that can result in brain damage and even death.
What bacteria cause bacterial meningitis?
Bacterial meningitis is most commonly caused by one of three types of bacteria:
Haemophilus influenzae type b (Hib),
Neisseria meningitidis, and
Streptococcus pneumoniae.
Where is bacterial meningitis found?
Bacterial meningitis is found worldwide. The bacteria
often live harmlessly in a person's mouth and throat. In
rare instances, however, they can break through the body's immune defenses and travel to the fluid surrounding the brain and spinal cord. There they begin to multiply quickly. Soon, the thin membrane that covers the brain and spinal cord (meninges) becomes swollen and inflamed, leading to the classic symptoms of meningitis.
How do people get bacterial meningitis?
The bacteria are spread by direct close contact with the discharges from the nose or throat of an infected person. Fortunately,
none of the bacteria that cause meningitis are very contagious, and they are
not spread by casual contact or by simply breathing the air where a person with meningitis has been. (So 'just living in the doormrooms is not enough).
What are the signs and symptoms of bacterial meningitis?
In persons over age 2, common symptoms are high fever, headache, and stiff neck. These symptoms can develop over several hours, or they may take 1 to 2 days. Other symptoms can include nausea, vomiting, sensitivity to light, confusion, and sleepiness. In advanced disease, bruises develop under the skin and spread quickly.
In newborns and infants, the typical symptoms of fever, headache, and neck stiffness may be hard to detect. Other signs in babies might be inactivity, irritability, vomiting, and poor feeding.
As the disease progresses, patients of any age can have seizures.
Who is at risk for bacterial meningitis?
Anyone can get bacterial meningitis, but it is
most common in infants and children (not college students). People who have had close or prolonged contact with a patient with meningitis caused by Neisseria meningitidis or Hib can also be at increased risk. This includes people in the same household or day-care center, or anyone with direct contact with discharges from a meningitis patient's mouth or nose.
How common is bacterial meningitis?
In the United States,
bacterial meningitis is relatively rare and usually occurs in isolated cases.
Clusters of more than a few cases are uncommon.
Most people with viral meningitis usually start getting better within 3 days of feeling sick and recover within 2 weeks. Bacterial or severe viral meningitis may require treatment in a hospital, including:
- Antibiotics: Antibiotics are given only when bacteria are causing the infection.
- If meningitis is causing pressure within the brain, corticosteroid medicines such as dexamethasone may be given to adults or children.
- Measures to reduce fever.
- Measures to prevent seizures.
- Oxygen therapy.
- Monitoring fluids. Liquids are given into a vein (IV) if you have an infection and are vomiting or are not able to drink enough.
- Monitoring blood chemicals. Frequent blood tests are done to measure essential body chemicals, such as sodium and sugar in the blood.
A person who has severe meningitis may need to be treated in the intensive care unit (ICU) of a hospital.
