Meningococcal Meningitis

Meningococcal meningitis is a severe bacterial infection of the meninges and the blood stream. This is disease is more common usually during late summer and early fall, but it can occur throughout the year. This medical condition is caused by a microorganism termed as meningococcus, scientific name: Neisseria meningitides. Among the several bacteria that can cause meningitis, Neisseria meningitides is one which is most important because it has the ability to potentially cause epidemics.

Bacterial meningitis is rarer but more difficult to cure compared to viral meningitis (a meningitis of which the causative agent is a virus rather than a baterium) on which a patient would usually recover without any form of treatment or medication. In the case of bacterial meningitis, a patient would require treatment of antibiotics and other prescription drugs. As a bacterial meningitis, meningococcal meningitis can cause very grave illness and requires immediate diagnosis and treatment, if the infection is untreated, it could be fatal.

Meningococcal meningitis only infect humans. It is also estimated that around 10 to 25% of the population carry the bacterium Neisseria meningitides, at any given time, and epidemic situations often results from a massive increase in carriage rate of the bacterium.

Haemophilus influenza (type B Hib) was the leading cause of bacterial meningitis before the late 1800s. At that time period, new vaccines have already been developed and administered to children as part of routine immunizations in order to reduce the occurrence of an epidemic outbreak caused by H. influenza.

An outbreak of the Meningococcal disease had first been recorded in Geneva Switzerland in 1805. But only in 1887, was Neisseria meningitides, the causative agent, identified. At present, the microbacteria neisseria meningitides is the   primary cause of bacterial meningitis.

There are twelve subtypes of serogroups of N. meningitidis that have been identified and four (N. meningitidis. A, B, C and W135) which are recognized and tested to cause epidemics.

The immunogenicity, pathogenicity, ability to cause an epidemic of the bacteria, would differ according to the serogroup. Therefore, identifying the serogroup responsible for the sporadic case is a very important step in containing the epidemic and in searching for a cure.

Meningococcal meningitis is a highly contagious disease and often occurs as an epidemic usually occurring at a place or a community wherein people live in close quarters with poor ventilation such as on military camps and college dormitories.

Usually, the neisseria meningitides micro bacterium, would easily spread with close contact on nose, throat and mucus discharges from an already infected person. While there are some who would carry this particular type of bacterium in their nose and throat, whithout showing any signs of illnesses, there are still those who may develop serious symptoms once exposed to the bacterium.

From the respiratory tract, the blood-borne bacterium, neisseria meningitides, will enter the cerebrospinal fluid (watery liquid surrounding the spinal cord) of an organism. Upon infection, the organism would release toxins into the spinal fluid and this would lead to an inflammatory reaction. Once neisseria meningitides enters the bloodstream, it can lead to several complications ranging from mild arthritis, to serious heart infection and pneumonia. It can even damage the nerves leading to the brain thereby causing motor impairment, retardation, and hearing loss.

Milder symptoms of meningococcal meningitis include headache, chills, fever, vomiting, rashes, stiff neck, and confusion, whereas the more severe symptoms include coma, seizures, shock and even paralysis.

            The symptoms commonly appear at around five days upon first exposure to the bacterium, although in some cases, bodily reactions to the bacterium can be delayed for up to ten days prior to exposure. Among the most common symptoms that can often tell whether a person is positive to meningococcemia is a combination of highfever, headache, and meningococcemic rash. Meningococcemic rash is usually non-blanching and would deveop rapidly. It usually appears on the groin, ankles, armpits, and other areas of the body where elastic pressure (from clothing like socks and underwear) is applied.

As for the diagnosis of a patient suffering from meningitis, it is important to determine whether the causative agent of the illness is a virus or a bacterium. This must always be taken into account since the severity of the illness and even the necessary treatments, would always differ. Viral meningitis would usually be less severe than bacterial meningitis and would usually be resolved without specific treatment. Once a proper diagnosis has been done to a patient and once the patient has been found to be positive with bacterial meningitis, the next step would be to determine which type of bacteria is causing the illness since some antibiotics are target specific.

A medical history and of the patient being diagnosed would be very helpful. Physical examinations would also help but all these would not be sufficient and would not be specific enough to complete the diagnosis. Usually, a lumbar puncture or a spinal cord tap must be administered to the patient. A spinal cord tap can be done by first, application of anaesthetic to the lower back, and extracting cerebrospinal fluid from the spinal canal using a hollow tube or needle.

The sample fluid would then be stained and cultured. The cultured samples will then be analyzed to determine the causative agent of the infection, and in order to find other signs of infection in the white blood cells, and other cells and tissues in the body.

Samples of urine, sputum, and blood should also be taken from a patient being diagnosed, and then analyzed. For patients suffering from meningococcal meningitis, chest x-rays and CT scans of the brain are taken and analyzed. From these, other sources of infection will be determined and other diagnoses would be ruled out. Identification of the correct strain of the bacterium causing the infection is very important in selecting the proper antibiotics.

For each hour of delay from the application of antibacterial therapy, a patients risk of having complications and permanent damages in the body specially in the nervous system increases exponentially. Antibacterial treatment and application of antibiotics such as penicillin G need to be done as early as possible in order to decrease the chance of developing complications. Prior to lumbar puncture diagnosis, antibiotics may already be administered and continued for up to 10 days.

An outbreak of meningococcal meningitis is indeed a great threat to public health and should always be taken seriously, but calmly.

People that have undergone prolonged exposure to people that are carriers of the bacterium, or have stayed in places that are know to be contaminated with the bacterium, should immediately be treated with preventive antibiotics. Among the most common preventive antibiotics that can be administered are ceftriaxone, ciprofloxacin and rifampin.  Casual and indirect contact with people infected by the disease need not be a cause of alarm or any medical concern.

            Several vaccines are available for the prevention of the spreading of the disease. A certain type of vaccine is the meningococcal polysaccharide vaccine. This type of vaccine is used to prevent infection by a specific and more common group of the meningococcal bacteriu. It works by helping the patients body develop its own antibodies that would counteract the disease. This vaccine however works effectively against A, C, Y and W-135 strains of Neisseria meningitides. The vaccine will not be effective against other groups of the bacterium such as the Group B. Certain criteria must be met before the vaccine is administered to an infected person. First, the person must be above two years of age, second, the person must be diagnosed and found positive of meningococcal infection and third, the infection has to be found to be caused by the A,C,Y and W-135 groups of the causative bacterium. For children under two years of age, an immunogenic, monovalent conjugate vaccine against the serogroup C may be administered. Other vaccines should be prescribed in the detection of other groups, and in other cases. Vaccines may be able to, but cannot assure complete protection for 10 to 14 days.

            Once a patient is confirmed to carry meningococcal disease, it must always be treated as a medical emergency. The person must be admitted to a hospital or a health care center as soon as possible. In milder cases, placing the patient under isolation would not be necessary. Antimicrobial therapy must be administered to the patient as soon as possible.

            Preparedness against the outbreak of an epidemic focuses on the surveillance from case detection and investigation to laboratory confirmation. Among the public, distribution of the idea of an epidemic outbreak of meningococcal meningitis should be done, in a manner that it will not cause panic or alarm. The whereabouts of the disease and the causative agent of the disease, as well as the preventive measures, diagnostic procedures and treatment, should be properly briefed to people that are immediate to an area where an epidemic has occurred. To prevent further spread of the disease, travelers to the areas affected by the epidemic should be prompted to take vaccines and other necessary preventive measures. Overseas travelers are advised to check if meningococcal vaccines are recommended on their country of destination. If so, they should receive the vaccine at least a week prior to his departure.

Other relevant information regarding meningococcal meningitis, vaccines, prevention, treatment and diagnosis, can be obtained from local Centers for Disease Control Prevention.

References

Acute and communicable disease prevention. Retrieved February 2, 2008, from:

http://www.oregon.gov/DHS/ph/acd/diseases/nmenin/facts.shtml

Information for a healthy New York. Retrieved February 2, 2008, from

http://www.health.state.ny.us/diseases/communicable/meningococcal/fact_sheet.htm

Meningococcal disease. Retrieved February 2, 2008, from

http://www.cdc.gov/ncidod/dbmd/diseaseinfo/meningococcal_g.htm

Meningococcal meningitis – Symptoms treatment and prevention. Retrieved February 2, 2008,

from: http://www.healthscout.com/ency/68/354/main.html