Meningococcal infections are caused by the bacteria Neisseria meningitidis (meningococci) and include meningitis and sepsis.
- Infection is spread by direct contact with nasal and throat secretions.
- People feel generally ill and have other, often serious symptoms, depending on the area infected.
- Identifying the bacteria in a sample taken from infected tissue confirms the diagnosis.
- Vaccination can help prevent meningococcal infections.
- Antibiotics and fluids must be given intravenously as soon as possible.
More than 90% of meningococcal infections are
- Meningitis: Infection of the tissues covering the brain and spinal cord (meninges)
- Sepsis: Infection of the bloodstream (called meningococcemia when caused by meningococci)
Infections of the lungs, joints, eyes, and heart are less common.
In temperate climates, most meningococcal infections occur during winter and spring. Local outbreaks can occur, most often in sub-Saharan Africa between Senegal and Ethiopia. This area, which includes 26 countries, is known as the meningitis belt.
Meningococci reside in the throat and nose of some people without causing symptoms. Such people are called carriers. People often become carriers after outbreaks. However, infection usually occurs in people who have not been exposed previously to meningococci, rather than in carriers. Infection is spread by direct contact with nasal and throat secretions of an infected person (including carriers).
Most commonly infected are
- Children aged 6 months to 3 years (see also Meningitis in Children)
Infections are also common among
- Military recruits
- College freshmen living in dormitories
- Travelers to places where meningococcal disease is common
- People with certain immune system disorders
- People whose spleen has been removed or damaged
- People who take eculizumab or ravulizumab (drugs that block a component of the immune system called the complement system)
- Microbiologists working with meningococci
Meningococcal disease is more common among people with AIDS than among the general population. Other factors that may increase risk include getting a viral infection, living in a crowded household, having a chronic illness, and smoking or being exposed to cigarette smoke (passive smoking).
Outbreaks account for only a small percentage of cases and tend to occur among people who spend time or live in close quarters with others, for example, in dormitories or day care centers, and often involve people 5 to 19 years of age.
Most people with a meningococcal infection feel very ill.
Meningitis often causes fever, headache, red rash, and a stiff neck. It can also cause nausea, vomiting, and sensitivity to light.
Infants may have feeding problems and a weak cry, and they may be irritable and sluggish.
Bloodstream infections may cause a rash of red or purple spots. A severe infection may cause dangerously low blood pressure (shock), a tendency to bleed, and dysfunction (failure) of many organs (such as the kidneys and liver).
Rarely, meningococcal infection causes a chronic illness that causes mild, recurring symptoms that mostly involve the joints and skin.
- Examination and culture of samples of blood or other infected tissues, including cerebrospinal fluid obtained by spinal tap
Doctors suspect meningococcal infection in people who have typical symptoms, particularly if symptoms occur during an outbreak.
To confirm the diagnosis, doctors take samples of blood or other infected tissues or do a spinal tap (lumbar puncture) to obtain a sample of the fluid that surrounds the brain and spinal cord (cerebrospinal fluid). The samples are examined under a microscope to check for and identify bacteria. The samples are also sent to a laboratory, where the bacteria can be identified after it is grown (cultured) or other laboratory tests are done.
Sometimes doctors do blood tests that detect antibodies to the bacteria or the capsule that encloses the bacteria. However, the results have to be confirmed by culture.
The bacteria may also be tested to determine which antibiotics are effective (a process called susceptibility testing).
Overall, 10 to 15% of people who have meningococcal infections die. Up to 40% of people with severe bloodstream infections die. Of people who recover, 10 to 20% have serious complications, such as permanent hearing loss, intellectual disability, seizures, or gangrene of the fingers, toes, or limbs, which may require amputation.
After exposure to meningitis
Family members, medical personnel, and other people in close contact with people who have a meningococcal infection should be given an antibiotic to prevent infection from developing. Antibiotics may be given by mouth or by injection. With most recommended antibiotics, only a single dose or at most 2 days of treatment are needed.
During an outbreak, meningococcal vaccine is also given (in addition to antibiotics) to people in close contact with a person who has a meningococcal infection.
For more information, see also Meningococcal Vaccine and the vaccine schedules for children and adults from the Centers for Disease Control and Prevention (CDC).
Meningococcal vaccines protect against specific types (called serogroups) of meningococci that cause most meningococcal disease: serogroups A, B, C, W, and Y.
Several types of meningococcal vaccine are available in the United States:
- MenACWY vaccines: These vaccines protect against meningococcal serogroups A, C, W, and Y. They are part of the routine childhood vaccination schedule and are recommended for all children at age 11 to 12 years, with a booster at age 16 years.
- MPSV4: This vaccine is given only to certain people over age 55 years.
- MenB vaccines: These vaccines protect against meningococcal serogroup B, which is a type of meningitis bacteria that has become common in outbreaks among college students.
Meningococcal vaccine is also recommended for the adolescents and adults who are at increased risk of meningococcal infection.
- Antibiotics given by vein (intravenously)
- Fluids given intravenously
- Possibly corticosteroids
People are usually admitted to an intensive care unit and given antibiotics and fluids intravenously as soon as possible, before doctors get the culture results identifying the organism causing the infection. If meningococci are confirmed, doctors change the antibiotics to those that are most effective against the bacteria, typically ceftriaxone or penicillin. These drugs are given intravenously.
Corticosteroids (such as dexamethasone) may be given to children and adults who have meningitis. These drugs help prevent brain damage.
The following are English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
See the following government sites for comprehensive information on everything from updates on outbreaks and risk factors to educational materials and quick links to related topics:
- Centers for Disease Control and Prevention (CDC): Meningococcal Disease
- Centers for Disease Control and Prevention (CDC): Recommended vaccine schedule for children 7 to 18 years old
- Centers for Disease Control and Prevention (CDC): Recommended vaccine schedule for adults
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