Meningitis

What are the causes of meningitis?

The most frequent are meningitis of infectious cause, produced by three different infectious agents:

• Viruses: viral meningitis are benign and usually resolve spontaneously within a few days. It is necessary to distinguish them from viral encephalitis (e.g. herpes encephalitis), which not only produce inflammation of the meninges but also of the brain and have a more serious prognosis.
• Bacteria: Bacterial meningitis is serious and requires urgent antibiotic treatment.  Bacteria that enter the bloodstream and travel to the brain and spinal cord can cause acute bacterial meningitis. Meningitis can also occur when bacteria invade the meninges directly from a nearby focus, such as an ear or sinus infection, a skull fracture or, in rare cases, after some surgeries.
• Pneumococcus and meningococcus are the bacteria responsible for more than half of the acute meningitis in our country. Pneumococcus is the most frequent cause of bacterial meningitis in infants, young children and adults.
• Meningococcal meningitis is a very contagious infection that mainly affects adolescents and young adults. It can cause a local epidemic in schools, residences, boarding schools and similar centers.
• Fungi: they are rarer and occur mainly in immunosuppressed persons, such as people receiving chemotherapy or immunosuppressive treatment (transplants, etc.).

How can it be prevented?

The prevention of meningitis is done through two main measures: vaccination and chemoprophylaxis.

Vaccination immunizes the individual against a germ and thus prevents him/her from acquiring the infection. The inclusion of conjugated vaccines against pneumococcus, meningococcus serogroup C and Haemophilus Influenzae type b in the systematic vaccination calendars has caused a significant decrease in the incidence of these diseases.

Chemoprophylaxis consists in the administration of an antibiotic during short periods of time to people who have been in contact with a patient diagnosed with meningitis. Not all types of meningitis require antibiotic prophylaxis for contacts. Pneumococcal meningitis (the most common type of meningitis) does not require chemoprophylaxis.

However, close contacts of patients with meningococcal meningitis are more likely to get the disease in the next 7 days, so chemoprophylaxis will be indicated in certain cases.

In case a case of meningococcal meningitis has been diagnosed, all those persons who had close contact with the index case in the previous 7 days shall take an antibiotic prophylaxis.

Close contact is defined as having had prolonged (8 hours or more) and close (90 cm is the general limit established for the dissemination of large droplets) contact with the case or having been directly exposed to the oral secretions (for example, by kissing on the mouth, performing mouth-to-mouth resuscitation maneuvers, etc.) of the patient during the week prior to the onset of symptoms and up to 24 hours after the beginning of the antibiotic treatment.

This group would include all members of the household (or comparable settings such as shared floors, etc.), fellow students, members and staff of the nursery or kindergarten classroom... It would not be justified, however, to administer chemoprophylaxis to all students attending the same primary, secondary, or university class or center, unless they have had close contact with the case.