Diseases & Conditions

Bacterial Meningitis


Overview, Causes, & Risk Factors

Bacterial meningitis is an infection of the membranes that cover the brain. It is caused by a bacteria.

What is going on in the body?

There are a number of different organisms that can cause bacterial meningitis. They generally begin growing in a person's nose and throat. If not stopped by the immune system, the bacteria go on to invade the body. They can enter the bloodstream and travel to the central nervous system.

The infection then settles in the fluid and the membranes around the brain. The resulting inflammation is responsible for many of the symptoms of meningitis. It may also play a role in some of the complications.

What are the causes and risks of the infection?

Bacterial meningitis is caused by a bacteria that usually enters the body through the person's nose or throat. The bacteria can be transmitted to newborns during labor and delivery. Many people can have the bacteria in their noses or throats without developing meningitis. The bacteria are more likely to cause meningitis in very young infants. People with a weakened immune system, such as those with AIDS, are also at high risk.


Symptoms & Signs

What are the signs and symptoms of the infection?

Symptoms of bacterial meningitis in people over the age of two may include:

  • confusion
  • drowsiness
  • fever
  • headache
  • light sensitivity
  • seizures
  • stiff neck
  • vomiting
  • An infant with bacterial meningitis may be irritable, feed poorly, and be slow or inactive.


    Diagnosis & Tests

    How is the infection diagnosed?

    Diagnosis of meningitis begins with a medical history and physical examination. The healthcare provider may then do a spinal tap. This procedure uses a thin needle to draw out cerebrospinal fluid, the clear fluid surrounding the brain and spinal cord. The fluid is sent to the lab for examination.

    Bacteria can often be cultured or grown in the lab from a sample of the fluid. This shows which germ is causing the infection. Chemical signs of the bacteria, called an antigen, can be helpful in cases in which the culture does not work.


    Prevention & Expectations

    What can be done to prevent the infection?

    Immunization with Haemophilus influenza type b vaccine (Hib) is very effective in preventing this disease. It is one of the recommended immunizations given to children. Due to this vaccine, this once-common cause of meningitis is now almost nonexistent.

    Vaccines do exist for other meningitis-causing organisms such as Neisseria meningitidis and Streptococcus pneumoniae. These vaccines are recommended in special cases, such as for college students living in dormitories.

    For an individual exposed to someone with bacterial meningitis, antibiotics may be given to prevent an active infection.

    What are the long-term effects of the infection?

    Bacterial meningitis can sometimes be fatal. Other long-term effects include hearing impairments; hydrocephalus, or fluid on the brain; brain damage; and loss of limbs.

    What are the risks to others?

    Bacterial meningitis is contagious. It can be transmitted to others through saliva or nasal secretions. The infection can be spread by kissing, as well as by sharing drinks, lip balm, lipstick, or cigarettes.


    Treatment & Monitoring

    What are the treatments for the infection?

    Bacterial meningitis may be treated with the following medications:

  • antibiotics, such as ampicillin, cefotaxime, or ceftriaxone
  • corticosteroids, such as methylprednisolone or prednisone, to decrease swelling in the brain
  • surgery to remove a brain abscess, or collection of pus
  • ventilators, if breathing is impaired
  • What are the side effects of the treatments?

    Antibiotics may cause stomach upset, rash, or allergic reactions. Corticosteroids can increase a person's risk of infection. Surgery may cause bleeding, infection, or allergic reaction to anesthesia.

    What happens after treatment for the infection?

    Once bacterial meningitis is treated effectively, the person can return to normal activities.

    How is the infection monitored?

    Any new or worsening symptoms should be reported to the healthcare provider.


    Attribution

    Author:Danielle Zerr, MD
    Date Written:
    Editor:Crist, Gayle P., MS, BA
    Edit Date:03/23/01
    Reviewer:Eileen McLaughlin, RN, BSN
    Date Reviewed:06/28/01