Meningitis can be a very serious disease. If you or someone you love is at increased risk for meningitis, you may have lots of questions. Here are answers to some of the most common questions about meningitis.
1. What is meningitis? Meningitis occurs when the membranes covering the brain and spinal cord, called the meninges, become inflamed. It is usually caused by an infection. This disease can be fatal or cause serious lasting side effects.
Despite its name, the bacterium called Haemophilus influenzae type b, or Hib, does not cause the flu. It does, however, cause Hib disease, a serious health threat to children, especially those under age 5. Fortunately, the Hib vaccine, available since 1992, provides safe and effective protection against that threat.
2. What are the causes of meningitis? The two main causes of meningitis are viruses and bacteria. Common bacteria or viruses may cause infection in a part of the body -- the skin, gastrointestinal tract, or respiratory tract, for instance. They then may spread through the bloodstream to the nervous system. Bacteria can also enter the nervous system directly after severe head trauma or head surgery, or following an infection in the head.
Fungi, protozoa, and other parasites are less common causes of meningitis. In very rare cases, cancer, other diseases, or certain medications may also lead to inflammation of the meninges.
3. What is bacterial meningitis? Bacterial meningitis is serious, occurring more often in winter months. A common cause affecting teens is the bacterium Neisseria meningitidis, which causes meningococcal disease. It can be fatal if you don't receive treatment right away. The bacteria that cause it live in the noses and throats of up to a quarter of the population. It is not known why these bacteria sometimes travel to the nervous system and cause meningitis. Another leading cause of bacterial meningitis is Streptococcus pneumoniae.
4. What is viral meningitis? Viral meningitis is more common and usually less serious. It tends to occur more often in the summer and fall. Because of its flu-like symptoms, many people mistake it for the flu. Viruses that cause "stomach flu" are a cause of viral meningitis, but most people who have these infections don't develop meningitis. Others viruses that lead to meningitis are those that cause chickenpox, mononucleosis (mono), and herpes. Symptoms can be similar to those of bacterial meningitis.