The mother of one of my patients asked me to write about meningitis. Meningitis is a very rare condition. The incidence of all types of bacterial meningitis in the United States is about two to three cases per 100,000 people per year, while viruses cause about 11 cases per 100,000 per year. I frequently witnessed the devastation of meningitis during my medical training in the late 1980s. However, with the advent of vaccines to prevent the most common causes of bacterial meningitis, physicians rarely see a case today.
Meningitis is a condition that causes inflammation of the meninges, the coverings surrounding and protecting the brain and spinal cord. Most of the symptoms of meningitis are caused by the inflammatory reaction of the body to infection by viruses and bacteria. Fungi or parasites occasionally cause infections as well. These microorganisms reach the meninges either through the bloodstream or by direct contact of the mininges with the nasal cavity or skin, usually through some type of trauma.
Meningitis, especially bacterial can be very serious if not diagnosed and treated promptly. Depending on the cause, death from meningitis occurs about 20 to 30 percent of the time in infants, about two percent in older children, and from 19 to 37 percent in adults.
Viruses are the most common causative agent in meningitis. Viral meningitis is usually caused by enteroviruses, herpes viruses, varicella (chickenpox) virus, mumps virus, measles virus, and HIV.
The type of bacteria that causes meningitis is dependent on the age of the patient. Babies up to the age of three months are usually infected by group B Streptococcus found in the mother’s birth canal, or other bacteria that inhabit the maternal or infant gastrointestinal tracts. Older kids are usually infected by meningococcus, Streptococcus pneumoniae (pneumococcus) and Haemophilus influenza type B (Hib). Adults usually are infected by meningococcus or pneumococcus.
The symptoms of meningitis vary based on the offending microorganism and age of the patient. Signs and symptoms in infants and toddlers can be very subtle. These may include fever, drowsiness, irritability, vomiting, or poor appetite. The fontanel or soft spot of the head may be swollen or bulging.
Signs and symptoms in older children and adults are usually more pronounced. Most have a headache, stiff neck and fever. Those who don’t have any of these three symptoms are very unlikely to have meningitis. Less common signs and symptoms may include confusion, loss of consciousness, sensitivity to light (photophobia), or noise (phonophobia). People with meningococcal meningitis may have a characteristic rash consisting of small reddish or purple spots.
Meningitis is definitively diagnosed by using a needle to obtain a sample of cerebrospinal (spinal) fluid from the space that exists between two of the three meninges. The procedure is commonly known as a lumbar puncture or “spinal tap.” The fluid is then analyzed for signs of inflammation or infection.
If the initial analysis indicates infection, antibiotics are usually started pending confirmatory lab tests. Steroids may also be given to reduce the immune response in the meninges. Intravenous fluids are usually given. If the cause is viral, antibiotics will not help and treatment is usually aimed at making the patient more comfortable until the body can clear the infection. There are also medications available for treatment of meningitis caused by herpes and varicella virus.
Some forms of bacterial meningitis are contagious. The most worrisome is meningococcal meningitis. It can be spread through the exchange of respiratory and throat secretions (i.e. coughing, kissing). It is not spread by casual contact or being in a room where a person with meningitis has been. People who live in close contact with a person with meningococcal disease are at risk. This is especially true of household contacts and those in dormitories or barracks.
Most types of meningitis can be almost completely prevented by vaccination. Standard early childhood vaccines protect against meningitis caused by viruses (measles, mumps, and varicella) and bacteria (pneumococcus and Hib). Vaccines are also available to prevent the most common types of meningococcal disease in older children. One type of vaccine is required in Indiana for children to enter 6th & 12th grades. Vaccine to prevent meningococcus type B is required to enter most public colleges in Indiana.
For more information on meningitis and vaccination, see www.cdc.gov/meningitis.

Dr. John Roberts is a licensed medical physician. He writes a weekly column exclusively for Sagamore News Media publications.