Meningitis affects the meninges, the membranes that surround the brain and spinal cord and protect the central nervous system (CNS), together with the cerebrospinal fluid.
In 2006, the mortality rate for bacterial meningitis was 34 percent, and 50 percent of patients experienced long-term effects after recovery.
For this reason, treatment with antibiotics must start as soon as possible.
Several types of bacteria can cause bacterial meningitis, including Streptococcus pneumoniae (S. pneumoniae) and Group B Streptococcus.
Other types of meningitis include viral, parasitic, fungal, and non-infectious meningitis, but the bacterial type is the most severe.
Vaccines have dramatically reduced the incidence of bacterial meningitis.
Fast facts on bacterial meningitis
Here are some facts about bacterial meningitis. More detail is in the main article.
- In the United States (U.S.) from 2003 to 2007, there were around 4,100 cases of bacterial meningitis each year, of which about 500 were fatal.
- Bacterial type is the second most common type viral meningitis, but it is more serious.
- Infants are at high risk of bacterial meningitis, and it spreads easily in places where many people gather, such as college campuses.
- Early signs include a fever and stiff neck, headache, nausea, vomiting, confusion, and increased sensitivity to light. Immediate medical attention is essential.
- Vaccination is important to prevent meningitis. Vaccines that protect against three types of bacterial meningitis are Neisseria meningitidis (N. meningitidis), Streptococcus pneumoniae (S. pneumoniae), and Hib.
Causes and risk factors
Meningitis is an inflammation of the meninges that cover the brain.
Bacterial meningitis can be caused by a range of bacteria, including:
- Haemophilus influenzae (H. influenzae) type B (Hib)
- Neisseria meningitides (N. meningitides)
- Streptococcus pneumoniae (S. pneumonia)
- Listeria monocytogenes (L. monocytogenes
- Group B Streptococcus
At different ages, people are more likely to be affected by different strains.
The bacteria that cause meningitis usually pass from one person to another, for example, through droplets in coughs and sneezes or through saliva or spit. Some types can spread through food.
Group B streptococcus can pass from mothers to newborns during delivery.
Some people are carriers. They have the bacteria, but they do not develop symptoms. Living in a house with either a carrier or someone who has meningitis increases the risk.
It is important to follow the recommended vaccination schedule to prevent meningitis. H. influenza is the main cause of bacterial meningitis in children under 5 in countries that do not offer the Hib vaccine.
Bacterial meningitis can happen at any age, but infants are more susceptible.
Other factors that increase the risk include:
Recurrent bacterial meningitis is possible but rare. Studies show that 59 percent of recurrent cases are due to anatomical defects, and 36 percent occur in people with a weakened immune system.
Meningococcal meningitis is caused by the meningococcus bacteria.
According to the Centers for Disease Control and Prevention (CDC), the symptoms of meningitis can appear either suddenly or over a few days. They normally emerge in 3 to 7 days after infection.
Early symptoms of meningitis include:
- nausea and vomiting
- headache and a stiff neck
- muscle pain
- sensitivity to light
- cold hands or feet and mottled skin
- in some cases, a rash that does not fade under pressure
Later symptoms include seizures and coma.
- breathe quickly
- refuse feeds and be irritable
- cry excessively, or give a high-pitched moan
- be stiff, with jerky movements, or listless and floppy
The fontanelle may be bulging.
Meningitis rash glass test
A meningitis rash occurs if blood leaks into the tissue under the skin.
It may start as a few small spots in any part of the body, then spread rapidly and look like fresh bruises.
The glass test can assist in identifying a meningeal rash.
- Press the side of a drinking glass firmly against the rash.
- If the rash fades and loses color under pressure, it is not a meningitis rash.
- If it does not change color, you should contact a doctor immediately.
The rash or spots may fade and then come back.
The incidence of meningitis in the U.S. has dropped considerably since its vaccine was introduction.
Treatment for bacterial meningitis normally involves admission to the hospital, and possibly an intensive care unit.
Antibiotics are essential, and these may be started before the results of tests come back, possibly before arrival at the hospital.
- Antibiotics: These are usually given intravenously.
- Corticosteroids: These may be given if inflammation is causing pressure in the brain, but studies show conflicting results.
- Acetaminophen, or paracetamol: Together with cool sponge baths, cooling pads, fluids, and room ventilation, these reduce fever.
- Anticonvulsants: If the patient has seizures, an anticonvulsant, such as phenobarbital or Dilantin, may be used.
- Oxygen therapy: Oxygen will be administered to assist with breathing.
- Fluids: Intravenous fluids can prevent dehydration, especially if the patient is vomiting or cannot drink.
- Sedatives: These will calm the patient if they are irritable or restless.
Blood tests may be used to monitor the patient's levels of blood sugar, sodium, and other vital chemicals.
Prevention and vaccinations
As several types of bacteria can cause bacterial meningitis, so a range of vaccines is necessary to prevent infection.
The first vaccine was created in 1981 to protect against 4 of the 13 subtypes of N. meningitides.
A survey of 17 million people in the U.S. found that the incidence of all types of meningitis fell by 31 percent from 1998 to 2007, after the introduction of routine vaccinations against meningitis-causing bacteria.
The meningococcal vaccine is the primary vaccine in the U.S. All children should have this at the age of 11 to 12 years and again at 16 years, when the risk of infection is higher.
The Hib vaccine protects children against H. Influenzae. Before its introduction in the U.S. in 1985, H. Influenzae infected over 20,000 children under 5 years annually, with a 3 to 6 percent mortality rate. Widespread vaccination has reduced the incidence of bacterial meningitis by over 99 percent.
The Hib vaccine is given in four doses at the ages of 2, 4, 6, and 12 to 15 months.
Side effects of the vaccines may include redness and soreness at the site of the injection and a fever. Always check with a doctor to ensure that no allergies to any part of the vaccinations are present.
To prevent the spread of bacterial meningitis and other diseases, it is important to practice good hygiene, such as frequent handwashing.
Being aware of the signs and symptoms of bacterial meningitis will make it easier to take immediate action can be taken if necessary.