Meningococcal infections are caused by the bacteria Neisseria meningtidis (meningococci). The two most serious and commonly seen are meningitis, an inflammation of the tissues around the brain and spinal cord, and meningococcemia, an infection of the bloodstream. A majority of meningococcal infections in adolescents and adults are now preventable with a vaccine.
What is going on in the body?
At any given time, a substantial fraction (5 to 30 percent) of people may carry meningococci in their noses and throats, usually without symptoms or problems.
Occasionally, either because a person has acquired an especially harmful strain of the organism, or has weakened immunity for some reason, the bacteria invade the tissues and cause serious illness.
If the infection spreads to the fluids and membranes that surround the brain and spinal cord, the body's immune system responds with an outpouring of inflammatory cells and chemicals that cause most of the symptoms we associate with meningitis.
Though bacterial meningitis is a very serious infection that makes a person quite ill, the appearance of these symptoms actually means that the person has survived long enough to mount a vigorous immune response. Though the disease may still have a fatal outcome, the person's chances are excellent if treated promptly and appropriately.
Meningococcemia, on the other hand, can progress so rapidly with nonspecific symptoms that by the time the condition is recognized, it is too late for treatment to save the person's life. Death occurs due to shock and circulatory collapse.
What are the causes and risks of the infection?
Meningococcal infections are caused by contact with people who carry the bacteria in their throats. Some people carry these bacteria in their throats all the time and never become ill. Others get a life threatening illness the first time they are exposed.
People who have a higher risk of meningococcal infection are the following:
children, especially younger children in a day care setting
people with weakened immune systems
those in crowded settings, such as a school, college dormitory, or military camps
- those with close contacts who develop this infection, such as friends or family members
What can be done to prevent the infection?
A person who has had recent close contact with someone diagnosed with a meningococcal infection needs preventive treatment with antibiotics. Close contact includes living in the same house. It also can mean being in the same closed setting, such as a classroom, or giving face to face care to a person in a medical setting.
In addition, people in contact with the sick person should be watched for signs of an infection. If these signs occur, further treatment is needed quickly.
An individual can lower the risk of meningococcal infections by avoiding contact with secretions from the mouth or nose of an infected person.
The following items should not be shared because they can carry these secretions:
- lipstick and lip balm
Recently, an improved vaccine against meningococcal meningitis was licensed and recommended for teenagers and for college students living in dormitories. The vaccine is effective against types of meningococci responsible for about two thirds of the disease in these age groups.
The vaccine should also be given to other individuals who are at high risk because of their medical conditions, or because they may be exposed to meningococci in the course of medical laboratory work.
How is the infection diagnosed?
Meningococcal meningitis is usually suspected from the history and physical examination. Meningococcemia may be suspected if the examiner thinks to look for petechiae, which may not be obvious at first.
The diagnosis of meningitis is confirmed with an examination of spinal fluid, the clear fluid surrounding the brain and spinal cord. This fluid is carefully drawn out using a thin needle inserted through the skin of the back into the spinal canal between the vertebrae. The fluid is sent to the lab for examination. White blood cells, not normally found in spinal fluid, usually make the fluid cloudy in a person with meningococcal meningitis.
Bacteria can often be seen in the lab on a stained preparation of the fluid. Within a day or two, the organisms can be grown in the laboratory, identified, and typed. This helps determine which antibiotics will best treat the infection.
Chemical signs of the bacteria, called antigens, can sometimes be found in the spinal fluid as well. These are helpful for diagnosing the infection if for some reason the bacteria will not grow in the lab.
Similarly, meningococcemia can be diagnosed quickly by visualization of the organisms in a stained preparation of the person's blood. A culture can confirm the exact identity of the organisms in a day or two.
Long Term Effects
What are the long-term effects of the infection?
Severe involvement of any area from a meningococcal infection may cause permanent effects. For instance, skin may become scarred from a severe rash. Permanent brain damage, most commonly resulting in hearing impairment, can be caused by meningitis. Severe blood infections or meningitis can result in death.
What are the risks to others?
A meningococcal infection is contagious. It is spread from person to person through droplets from the infected person's nose or mouth.
What are the treatments for the infection?
Meningococcal infections are treated with antibiotics, including:
penicillin or ampicillin
cefotaxime (i.e., Claforan)
ceftriaxone (i.e., Rocephin)
chloramphenicol (i.e., Chloromycetin)
Many times, corticosteroids, such as dexamethasone (i.e., Decadron) will be used.
Other treatments may be used to treat complications, such as low blood pressure or bleeding problems. Rarely surgery is needed to remove a brain abscess, or collection of pus. A ventilator will be used if breathing is impaired.
What are the side effects of the treatments?
Antibiotics may cause stomach upset, rash, or allergic reactions.
What happens after treatment for the infection?
The person's close contacts will need to be alerted and treated with antibiotics. Outbreaks of meningococcal disease, which occur occasionally, have been more successfully managed with meningococcal vaccine than with antibiotics. Specific recommendations are available from the Centers for Disease Control and Prevention (CDC).
Once recovery begins, most people regain normal health and need no further treatment or monitoring. Others may have permanent problems, such as hearing impairment, that require further treatment. Death is possible if treatment is delayed or unsuccessful.
How is the infection monitored?
A person with a meningococcal infection is usually kept in the hospital for a few days. Once a person is better, he or she may be able to finish taking the antibiotics at home. Any new or worsening symptoms should be reported to the healthcare provider.
Harrison's Principles of Internal Medicine, 1998, Fauci et al.