Meningitis

Meningitis

What is meningitis?

Ilustration of the meninges
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Meningitis is a disease caused by an inflammation of the meninges, the membranes that surround the brain. The inflammation is usually caused by infection of the fluid surrounding the brain and spinal cord. There are three meninges, including the following:

What causes meningitis?

There are two distinct types of meningitis, each with different causes:

Viral (caused by a virus)
  • Viral meningitis is more common than bacterial meningitis, although rarely life threatening. Viral meningitis can be caused by different viruses, and is spread between people by coughing or sneezing, or through poor hygiene. Other germs can be found in sewage polluted water. On rare occasions, certain insects, such as mosquitos or ticks, are thought to convey these viruses. Insect bites would then be the way the virus is introduced into a patient, with the spread of the virus from the blood to the brain.
  • Viral meningitis can in a rare circumstancet be helped by special anti-viral medications that specifically target certain viruses. Recovery is normally complete, but headaches, fatigue, and depression may persist.
Bacterial (caused by a bacterium)
  • Bacterial meningitis, although rare, may be fatal.
  • Bacteria may be spread through the exchange of respiratory and throat secretions, such as coughing and kissing.
  • Many species of bacteria can cause meningitis. Below are four types:
    • Neisseria meningitidis (meningococcus). Meningococcus is a common cause of bacterial meningitis in children two to 18 years of age. It is spread by respiratory droplets and close contact. For unknown reasons, only a small fraction of carriers develop meningitis. Meningococcal meningitis occurs most often in the first year of life, but may also occur in closed populations, such as schools.
    • Streptococcus pneumoniae (pneumococcus). Pneumococcus is the most common and most serious form of bacterial meningitis. Those at high risk may include persons with weakened immune systems.
    • Haemophilus influenzae type b. The development of the Haemophilus influenzae type b vaccine has drastically decreased the number of cases in the U.S. Children who do not have access to the vaccine and those in day-care centers are at higher risk of acquiring Haemophilus meningitis.
    • Listeria monocytogenes. Listeria monocytogenes has become a more frequent cause of meningitis in neonates, pregnant women, people over the age of 60, and in people of all ages who are immunocompromised.

How does the infection reach the brain?

The infection can reach the brain via several different routes, including through the bloodstream from another infected part of the body, through the bones of the skull from infected sinuses or inner ears, or from a head injury, such as a fractured skull or penetrating wound. In particular, this occurs when the body's resistance is compromised by certain factors, such as following surgery or an extended hospitalization, a weakened immune system, or as a result of chronic kidney failure.

What are the symptoms of meningitis?

The following are the most common symptoms of meningitis. However, each individual may experience symptoms differently. Symptoms may include:

Symptoms for children may also include:

It is important to note that these symptoms may not occur all at once, nor in everyone who contracts meningitis. The symptoms of meningitis may resemble other conditions or medical problems. Always consult your health care provider for a diagnosis.

How is meningitis diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for meningitis may include the following:

Treatment for meningitis

Specific treatment for meningitis will be determined by your health care provider based on:

Treatment may include:

What is supportive therapy for meningitis?

While a person is recovering from meningitis, other therapies may be initiated to improve healing and comfort, and provide relief from symptoms. These may include the following:

In addition, supplemental oxygen or mechanical ventilation (respirator) may be required if you become very ill and have difficulty breathing.

Prevention of meningitis

Several vaccines are currently available to prevent some of the bacterial organisms that can cause meningitis. However, routine vaccination with these vaccines is recommended primarily for infants and children. Two doses at ages 11 through 18 are also recommended.

In certain conditions, your health care provider may recommend one of the meningitis vaccines. These conditions may include, but are not limited to, the following:

If you have questions regarding prevention, consult your health care provider.

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