La meningitis is a inflammation ofs meninges : the envelopes of the spinal cord and the brain in which the cerebrospinal fluid circulates.

In most cases, meningitis is caused by a virus (viral meningitis). Meningitis can also be caused by bacteria (bacterial meningitis). Bacterial meningitis is usually much more serious as viral meningitis and requires extremely urgent care.

In very rare cases, the disease may be due to certain types of cancer, an inflammatory disease such as lupus, an infection from a champignon or an allergic reaction to a drug, for example Motrin®, Advil® or the antibiotic ciprofloxacin (Cipro®).

Meningitis of viral origin

This form of meningitis at first looks like a influenza and rarely causes complications. Generally, the cold symptoms then appear signs of meningitis. These signs go away on their own after 2 weeks. But as at the beginning, we do not know if the meningitis is benign (due to a virus) or perhaps serious (due to a bacteria), we hospitalize the child for a while.

Viral meningitis more commonly affects children and and young adults. As with most viral illnesses, this meningitis cannot be cured with antibiotics. This fact sheet focuses on the bacterial meningitis.

Meningitis of bacterial origin

La bacterial meningitis is worse. It can progress extremely quickly, cause serious complications (deafness, brain damage, epilepsy, mental impairment, attention or learning disorders) and sometimes lead to mort (5% of cases) if it is not detected and treated in time. It’s an emergency. It mainly affects children adolescents and young adults.

There are several types of bacterial meningitis, depending on the bacteria involved:

• Pneumococcal meningitis (Streptococcus pneumoniae). The pneumococcal bacteria are the 1^re causes meningitis in North America, both adults and children². It can also cause pneumonia and otitis media. Natural immune protection against pneumococcus is acquired only around the age of 5 years. Susceptibility to infections of this type is greatest before the age of 2 years. There is also streptococcus pyogenes or Streptococcus agalactiae meningitis.
• Hib meningitis (Haemophilus influenzae type B). Prior to the 1990s, it was the main form of bacterial meningitis in children under 5 years old. Widespread use of Hib vaccine has dramatically reduced its reach³. THE’H. influenzae is also a common cause ofear infections, sinusitis and bronchitis. However, note that the Hib vaccine does not protect against these other conditions, rarely caused by the “type B” strain of this virus;
• Meningococcal meningitis (Neisseria meningitidis). This bacteria is the only one that leads to epidemics of meningitis. It is known to be present in the back throat or nose of 10% to 25% of the population, according to the World Health Organization, without causing disease. In rare cases, it overwhelms the body’s natural defenses and leads to meningitis;

   

  A more serious form of infection occurs if bacteria get into the bloodstream and organs; we are talking about meningococcemia. 13 strains of Neisseria m. The strains A, B and C are most often involved in epidemics. Type B and C strains predominate in America and Europe today, while type A strain predominates in Africa and Asia⁴;

   

• Listeria meningitis (Listeria monocytogenes). Infection with Listeria monocytogenes, or listeriosis, is usually mild in an adult but can be passed to babies and young children, in whom it can lead to meningitis. The pregnant women are particularly vulnerable (20 times more than the general population) and can transmit the infection to the unborn child². This bacterium, found in water and soil, can contaminate plants and animals and enter the food chain.

  See our text: Listeriosis: what you need to know.

Contagion

Bacterial meningitis can be transmitted by close contact et extended with an infected person. The majority of people exposed to the bacteria do not get the infection⁵. In addition, in most of those who contract it, meningitis does not develop.

La bacterium is conveyed by the saliva and secretions originating from the nose and throat. It can be contracted by breathing in particles of saliva present in the air when the person has coughed, sneezed or blown their nose, the bacterium is also transmitted by the saliva present during kisses on the mouth, by sharing utensils, glasses, water bottles, cigarettes, lipstick, etc.

Frequency and epidemics

La bacterial meningitis is a relatively rare disease with an overall incidence maintained at 2 cases or less per year per 100 population in Canada.

However, with regard to meningococcal meningitis, responsible for epidemics, the number of new cases increases and decreases in irregular cycles, without being able to identify trends. In Canada, periods of increased meningococcal activity occur approximately every 10 to 15 years. THE’hiver and spring are the periods favorable to epidemics in the temperate regions of the globe, while in the tropics, the dry season is the most affected.

Due to routine vaccination in babies and toddlers, the median age of Americans with bacterial meningitis fell from 15 months in 1985 to 25 in 1995⁶.

In France, in 2014 (11), 1220 meningitis were observed, i.e. 1,9 cases per 100 people.

(with 57 meningitis due to haemophilus influenzae, 330 meningitis due to Neisseria meningitidis (meningococcus), 550 due to streptococcus pneumoniae, 41 to streptococus pyogenes, 139 to streptococcus agalactiae 103 to Listeria monocytogenes).

Possible complications

Infections with meningococci are a medical emergency, they require early diagnosis, hospitalization and immediate antibiotic treatment. The longer the treatment, the greater the risk of neurological sequelae or death increases. Hearing loss, vision problems (which can go as far as blindness), speech difficulties, learning disabilities, epilepsy are some of the possible sequelae. The infection can even cause paralysis or gangrene of the hands or feet which may require amputations. Studies indicate that 15% to 20% of infants and toddlers who survive bacterial meningitis have permanent neurological sequelae.³.

When a bacterial infection affects the central nervous system, it can cause mort in a few days and even, sometimes, in a few hours. Meningococcal disease is fatal between 5 and 15% of cases⁷.