Meningitis is an inflammation of the membranes that surround the brain and spinal cord. It can be caused by viral or bacterial organisms. Cultures and serologic testing are used to identify the specific cause. However, because it is clinically difficult to distinguish viral from the less common bacterial causes, suspected cases of meningitis are usually hospitalized. Antibiotics are usually initiated pending the results of cultures of the spinal fluid that are generally needed to make a conclusive diagnosis. Prophylactic administration of antibiotics may often be given to close contacts as well because a conclusive diagnosis may not be immediately available.
Viral meningitis is a relatively common but rarely serious process that can be caused by one of several different viruses. Symptoms can include fever, headache and rash and may last 10 days. Treatment is usually directed at making the patient feel more comfortable and antibiotics are not indicated. Contacts do not need to be treated.
Bacterial meningitis is a serious acute infection characterized by sudden onset of fever, intense headache, nausea and often vomiting, stiff neck and frequently a purple / red spotted rash. Symptoms can escalate rapidly. It is spread by one to one contact, including respiratory droplets from the nose and throat of infected people. Treatment is antibiotics. Close contacts of a suspected or confirmed case of meningitis are often treated with prophylactic antibiotics to minimize the spread of the disease. The meningococcal vaccine provides protection from some but not all of the types of bacteria that can cause meningitis.
Close contact with an ill person is defined as participating in activities that involve an exchange of saliva (kissing or other intimate contact, sharing of food, utensils or oral personal hygiene items, etc.) Since the bacterial meningitis organism is present in the nasopharynx of a significant proportion of healthy individuals (5 to 10% of people may be asymptotic carriers), transmission is via respiratory exposure or direct contact with secretions (saliva). It remains poorly understood why a tiny fraction of the population develops this illness while many people carry this bacterium around without any ill effect. In those who are susceptible, the incubation period varies from 2 to 10 days. Illness most commonly occurs 3 to 4 days after exposure.
Meningococcal vaccine provides protection from some, but not all, of the types of bacteria that can cause bacterial meningitis. It remains effective against four (types A, C, Y and W-135) of the nine serogroups of the bacterium know to cause the disease. It has an efficacy rate of about 90% for these serotypes in persons over the age of five years. The present vaccine does not cover the type B serogroup, which causes approximately 30 % of cases in this country and the majority of cases in endemic foreign countries. Also, the vaccine does not eradicate the presence of the organism in the nasopharynx of those who are carriers. The annual incidence of meningococcal infection in college students is estimated to be about 1.3 per 100,000 students. Harvard requires all freshmen to be immunized against meningitis since information from the Center for Disease Control suggests that bacterial meningitis may be more common among young adults living in communal dormitory settings for the first time.
Like many other communicable diseases, some of the most important preventive measures are centered on simple good hygiene:
- To protect others, always cover the nose and mouth when coughing or sneezing
- Dispose of used tissues and other similar objects appropriately
- Do not share glasses, eating utensils, etc. – those on athletic teams should not share water bottles, cups, etc.
- Do not share personal hygiene items such as toothbrushes, bathroom glasses etc.
- Wash hands frequently – very, very important!
Any complaints of significant headache or stiff neck, especially with a sudden onset, need immediate attention. Other symptoms like fever, nausea, etc. may mimic the symptoms of different more routine acute illnesses and should be evaluated carefully.