Meningitis is an inflammation of the meninges, which are layers of tissue covering the brain and spinal cord. Encephalitis is an inflammation of the brain. Many of the pathogens responsible for meningitis, especially the viral agents, also cause encephalitis. In most instances, meningitis is due to infection; the causative organisms may include bacteria, viruses, protozoans, fungi or rarely other microorganisms. Meningitis may be a mild illness or it could be life threatening.
Aseptic meningitis, which is usually caused by viruses, is the most common type of meningitis seen in adolescents and is usually seen in individuals under age thirty years. During the warmer months, the enteroviruses are the most commonly identified cause of aseptic meningitis. It is thought that warm weather and wearing sparse clothing may facilitate the transfer of this virus, which may appear in oral secretions or fecal matter. Enteroviruses have also been recovered from houseflies, sewage and wastewater. Other viruses that may cause meningitis include mumps, herpes and the human immunodeficiency virus.
Bacteria may also cause meningitis in adolescents. The most common bacterial agents causing meningitis in patients sixteen years and older include Hemophilus, Pneumococcus, Listeria and Meningococcus.
Who is likely to develop meningitis?
Pneumococcal and Hemophilus meningitis is much higher in African American and Native American populations including Navajos, Apaches and Inuits. Sickle cell disease will increase the susceptibility of African Americans to pneumococcal bacterial infections. Poverty, overcrowding and limited access to health care are socioeconomic factors that appear to have a significant impact on the incidence and distribution of meningitis.
Clusters or epidemics of meningococcal disease including meningitis have been reported among adolescents with increasing frequency during the past fifteen years. The clusters have been reported mostly in secondary schools, although some clusters have been reported in colleges and universities. Recent studies have shown that college freshmen who live in dormitories are at increased risk of contracting meningococcal disease. Meningococcal disease may present as bacterial infection in the blood, meningitis or both.
What are the symptoms of meningitis?
In bacterial meningitis, symptoms may include fever, headache, seizures, vomiting, impaired consciousness, stiff neck and stiff back. In about twenty-five percent of cases, the adolescent becomes seriously ill within twenty-four hours without any antecedent illness. In about half of the cases of bacterial meningitis, the illness develops over one to seven days and is associated with respiratory symptoms. And in slightly less than twenty percent of patients, the meningeal symptoms develop after one to three weeks of respiratory symptoms.
The symptoms of aseptic meningitis are similar regardless of the virus involved. Usually the onset is relatively acute; some patients have a flu like illness before the onset of symptoms. Patients often have an intense headache with malaise, nausea, vomiting, listlessness and sensitivity to light. Fever and neck stiffness are usually present. Impaired consciousness usually is not seen in aseptic meningitis. If the mumps virus is the cause of the meningitis, then the patient may have swollen parotid glands. If herpes is the cause, then the adolescent may have sores in his or her mouth or on the genitalia.
How is meningitis evaluated?
Meningitis is an emergency medical condition. Adolescents with symptoms suggestive of meningitis should be seen immediately in a medical facility. A thorough medical examination is indicated. Blood testing and a spinal tap are usually done if meningitis is suspected, although in epidemics of aseptic or viral meningitis, the spinal tap may be deferred. X-rays may be performed to search for a focus of infection especially if the adolescent has bacterial meningitis. The spinal fluid is analyzed for presence of bacteria; infectious cells and the sugar and protein levels are measured. Samples of the spinal fluid are sent to the laboratory to culture for bacteria and occasionally viruses or tuberculosis depending on the clinical situation.
How is meningitis treated?
Patients with bacterial meningitis are hospitalized and treated with antibiotics. Frequently these patients are placed in the intensive care unit and may require medications for pain relief, prevention of seizures and reduction of brain swelling. Occasionally, respiratory support is necessary. If there are other complications due to the bacterial agents, then these need to be treated and monitored closely.
Most viruses that cause aseptic meningitis cannot be treated with medication. However, herpes and varicella viruses may be treated with antiviral medications. Patients may be hospitalized with aseptic meningitis for support and pain relief. It is not uncommon for patients to be treated initially with antibiotics and when the cultures are shown to be negative, the antibiotics are discontinued.
How is meningitis prevented?
Some immunizations will lower the risk for meningitis. The meningococcal vaccine, which some physicians strongly recommend for all students entering the freshmen year of college, will lower but not completely eliminate the chance for meningococcal meningitis. For adolescents with sickle cell disease or some other immune disorders, the pneumococcal vaccination will reduce the chance for pneumococcal meningitis. The mumps and varicella vaccinations are effective in preventing these diseases. Measles and polio vaccines help to prevent central nervous system infection with these viruses. Although Hemophilus is uncommon as a cause of meningitis for adolescents, the childhood vaccination against this bacterium may help to prevent some cases of meningitis in adolescents.
Since genital herpes infections may lead to infections of the central nervous system including meningitis, then safer sex methods including condom use during sex may be preventative. Early treatment of genital herpes infections may also prevent spread of the virus to the central nervous system.
Common sense may also help to prevent these infections. Adolescents should not share drinks, cigarettes, utensils or toothbrushes. Washing one’s hands after using the toilet and before eating may also help to prevent the spread of certain viruses. And adolescents should not drink water if there is a question of its safety.
More information is needed to understand why college freshmen are at higher risk for meningococcal disease. Risk factors for college students noted in recent research studies have implicated consumption of alcohol, campus bar patronage and cigarette smoking. Meningococcal disease and meningitis occurred in military recruits, but has been reduced considerably since the meningococcal vaccine has been mandated for all newly recruited members of the armed services. Now the meningococcal vaccine is recommended for students entering college as well as those who are around twelve years old.
Related topics:
Brain disorders, encephalitis, herpes, immunizations, seizures, sickle cell anemia
