Alternative Names Neisseria meningitidis infections, meningococcus infections
Definition Meningococcal infections are caused by the bacteria Neisseria meningitidis.
What is going on in the body? The Neisseria meningitidis bacteria most commonly causes blood infections and meningitis, an infection of the lining around the brain. The bacteria are usually spread from person to person through coughing or sneezing. The bacteria then go into the throat, where they may spread into the bloodstream and other areas of the body.
What are the signs and symptoms of the infection? Symptoms of meningococccal infections often start when the bacteria get into the bloodstream and get worse quickly. Signs and symptoms may include:
Other commonly affected areas of the body include the joints and the lungs. Joint infections can cause the joints to be painful, swollen, red, and hot. Lung infections can cause chest pain, cough, and shortness of breath.
What are the causes and risks of the infection? Meningococcal infections are caused by coming into contact with people who carry the Neisseria meningitidis bacteria in their throats. Some people carry these bacteria in their throats all the time and don't get sick. Others get a life threatening illness the first time they are exposed to these bacteria. Individuals who have a higher risk of meningococcal infection include:
those with close contacts who develop this infection, such as friends or family members
children, especially younger children in a day care setting
those in crowded settings, such as a school, college dormitory, or military camps
people with weakened immune systems
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. Close contact includes living in the same house or being in the same closed setting, such as a classroom. Treatment involves receiving an antibiotic to prevent catching the infection. In addition, contacts of the sick person should be watched for signs of an infection. If these signs occur, further treatment is needed quickly.
There is also a vaccine that is used in certain settings. It only protects against certain types or strains of these bacteria. It is usually only given during large outbreaks. The most common strain of meningococcus is a strain B, for which the present vaccine offers no protection.
How is the infection diagnosed? The Neisseria meningitidis bacteria can be found in the blood and spinal fluid. A sample of spinal fluid, which surrounds the brain and spinal cord, is obtained with a spinal tap.
A culture of blood or spinal fluid is often done. To do a culture, a sample of the fluid of interest is put into a special container. Inside the container is "food" that allows the bacteria to grow. If the bacteria grow, they can be identified in the laboratory. Culture of other infected areas, such as joint fluid or a piece of skin affected by a rash, can also be done.
A newer test called an antigen test can be done on the spinal fluid. This test can sometimes give results in less than an hour, while a culture may take 24 hours to grow bacteria.
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 occur from meningitis. Severe blood infections or meningitis can result in death.
What are the risks to others? A meningococcal infection is often contagious and puts others at risk.
What are the treatments for the infection? The most important treatment for meningococcal infection is antibiotic therapy. Ceftriaxone is a commonly used antibiotic, but first line treatment if meningococcal meningitis is suspected is to give IV benzyl penicillin. If possible a blood sample should be collected prior to giving the penicillin but it should not delay treatment. Preferably the antibiotic should be given prior to referral to a hospital emergency department.
Other care is given as needed, such as if low blood pressure or problems breathing occur.
What are the side effects of the treatments? Ceftriaxone and penicillin may result in allergic reactions or stomach upset. Other antibiotics may be used and each has its own possible side effects.
What happens after treatment for the infection? The person's close contacts will need to be alerted and treated with antibiotics. Most people recover completely 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 monitored 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 doctor.
Author: Danielle Zerr, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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