Contents
What is bacterial meningitis?
Meningitis is an inflammation and infection of the meninges, the thin membranes that surround the brain and spinal cord (the central nervous system). The infection can be caused by a virus (viral meningitis), bacteria (bacterial meningitis), or even a fungus or parasite.
In the case of bacterial meningitis, different families and types of bacteria can be involved. In all cases, treatment is based on the prescription of antibiotics, usually intravenously.
Pneumococcal meningitis
The pneumococcus, of its Latin name Streptococcus pneumoniae, is a family of bacteria capable of causing several more or less serious diseases, from sinusitis to pneumonia, including meningitis or otitis.
The pneumococcus is a bacterium which can be naturally present in the nasopharyngeal sphere (nose, pharynx and possibly mouth) of “healthy carriers” without causing symptoms. However, if it is transmitted to an individual who does not have it and / or whose immune defenses are insufficient, it can lead to otitis, sinusitis, or even pneumonia or meningitis if Streptococcus pneumoniae enters the bloodstream and reaches the meninges.
The mortality from pneumococcal meningitis is higher in the elderly as well as in young children and babies. However, this type of meningitis does not lead to epidemics as can be seen in the case of bacterial meningococcal meningitis.
Neisseria Meningitidis : the case of meningococcal meningitis
As its name suggests, the bacteria Neisseria meningitidis, from the meningococcal family, mainly causes meningitis. There are 13 strains, or serogroups of this bacterial family. These include meningococcal meningitis type B and type C, the most common in Europe, as well as strains A, W, X and Y.
In France in 2018, according to data from the National Reference Center for Meningococci and Haemophilus influenzae from the Institut Pasteur, among the 416 cases of meningococcal meningitis for which the serogroup was known, 51% were serogroup B, 13% were C, 21% of W, 13% of Y and 2% of rare or non-serogroupable serogroups.
Note that the bacteria Neisseria meningitidis is naturally present in the ENT sphere (throat, nose) from 1 to 10% of the population (outside the epidemic period), according to the World Health Organization (WHO). But it happens that this bacterium overwhelms the immune system and triggers meningitis, especially in infants, young children, adolescents or young adults, and immunocompromised patients.
Listeria, Haemophilus influenzae et Escherichia coli, other bacteria involved
Well known to pregnant women, the Listeria is an infectious agent which causes listeriosis in fragile subjects, but which can also cause meningitis. Hence the importance of follow dietary and hygiene recommendations during pregnancy and early childhood, among others in avoiding cheese and dairy products made from raw milk, raw, smoked or undercooked meat, etc. Listeria monocytogenes is transmitted through the digestive tract when contaminated dairy products or cold meats are consumed.
Other types of bacterial meningitis exist, in particular that linked to bacteria Haemophilus influenzae (Hib), which was still very common in France a few decades ago. The vaccine againstHaemophilus influenzae, first advised and then made compulsory, has reduced the incidence of this type of meningitis and pneumonia caused by this bacteria.
There are also meningitis linked to bacterium Escherichia coli, who can be foodborne, during vaginal birth, due to contact with the mother’s genital area. Low birth weight babies and premature babies are most at risk.
The infectious agent of tuberculosis can also cause meningitis in immunocompromised individuals.
Contagion: how do you catch bacterial meningitis?
Transmission of bacterial meningitis, whether due to pneumococcus or meningococcus, occurs through close, direct or indirect and prolonged contact with nasopharyngeal secretions, in other words by the saliva droplets, the cough, the postillions. The use of contaminated objects (toys, cutlery) can also transmit the bacteria, which will either be confined to the ENT sphere or reach the meninges, especially in immunocompromised patients, infants and young children.
Note that pneumococcal meningitis can also occur after a head trauma, which will create a breach in the meninges. This is called post-traumatic meningitis. Pneumococcal meningitis can also occur after a classic ENT infection (otitis, cold, bronchiolitis, flu…).
Symptoms of bacterial meningitis
Bacterial meningitis includes two main types of symptoms, namely:
- un infectious syndrome, grouping together the signs of an infection such as high fever, severe headaches, vomiting (especially in jets);
- and meningeal syndrome, sign of inflammation of the meninges, which results in a stiff neck, confusion, disturbances of consciousness, lethargy, sensitivity to light (photophobia), even a coma or a seizure.
Symptoms that are sometimes difficult to spot in the baby
Note that in young children, and especially infants, the symptoms of meningitis can be nonspecific and be difficult to spot.
Some present a pallor or a gray complexion, seizures or muscle twitching. The toddler can refuse to eat, to be in a state of drowsiness unusual, or prone to constant crying, or be particularly agitated. a bulging of the fontanel from the top of the skull and hypersensitivity to touch can also be observed, although this is not systematic.
In all cases, a sudden high fever should lead to an emergency consultation.
Le purpura fulminans, a vital emergency
The presence of red or purplish spots, called purpura fulminans, East a criterion of extreme gravity bacterial meningitis. The appearance of such spots on the skin should lead to urgent care, with a view to immediate hospitalization. If a purpura has appeared and associated with symptoms of meningitis, the administration of antibiotic treatment is started as soon as possible. The onset of purpura due to meningitis is a absolute urgency, because it is a threat of septic shock, which is life-threatening (we often speak of lightning meningitis).
As the clinical signs are relatively close between meningitis due to a virus or bacteria, it is cerebrospinal fluid analysis, taken from the spine during a lumbar puncture, which will make it possible to know whether the meningitis is of bacterial origin or not. If the appearance of the liquid taken can already give an idea of the type of meningitis in question (rather purulent in the presence of bacteria), the detailed analysis of the sample will make it possible to know which germ is the cause and therefore to adapt the antibiotic treatment accordingly.
Bacterial meningitis: protection requires the vaccine
The prevention of bacterial meningitis largely depends on the application of the recommendations of the vaccination schedule. In fact, vaccination protects against various germs that can cause meningitis, in particular Streptococcus pneumonia, certain serogroups of the bacteria Neisseria meningitidis, et Haemophilus influenzae.
Meningococcal vaccine
Vaccination against meningococcal serogroup C is compulsory in infants born from January 1, 2018, and recommended for children born before this date according to the following scheme:
- for infants, a vaccination at 5 months, followed by a dose of booster at 12 months of age (with the same vaccine if possible), knowing that the 12-month dose can be co-administered with the MMR (measles-mumps-rubella) vaccine;
- From the age of 12 months and up to the age of 24, for those who have not received a previous primary vaccination, the scheme consists of a single dose.
Meningococcal type B vaccine, called Bexsero, which is recommended and reimbursed only in certain specific situations, in particular in fragile people at risk or in an epidemic situation. ;
The meningococcal conjugate tetravalent vaccine against serogroups A, C, Y, W135, also recommended in specific situations.
Vaccination against pneumococcal infections
Vaccination against pneumococcal infections is compulsory for infants born from January 1, 2018, according to the following scheme:
- two injections two months apart (two and four months);
- a booster at the age of 11 months.
After the age of 2 years, vaccination is recommended for children and adults at risk with immunosuppression or a chronic disease leading to the occurrence of a pneumococcal infection (diabetes in particular). It then includes two injections spaced 2 months apart, followed by a booster seven months later.
Haemophilus influenzae type B vaccine
Vaccination against the bacteria Haemophilus influenzae type B is compulsory for infants born on or after January 1, 2018, and recommended for children born before that date, combined with diphtheria, tetanus and polio (DTP) vaccines:
- an injection at two months and then at four months;
- a recall at 11 months.
Un catch-up vaccination can be done up to the age of 5. It then includes two doses and a booster if the child is between 6 and 12 months old, and a single dose beyond 12 months and up to the age of 5 years.
It should be noted that these vaccines have made it possible to reduce the number of cases of bacterial meningitis in infants and young children, as well as deaths linked to these serious diseases.
Vaccination not only allows individual protection, it limits the spread of these bacteria and therefore protect those who cannot receive the vaccine, especially newborns and immunocompromised patients.
sources:
- https://www.pasteur.fr/fr/centre-medical/fiches-maladies/meningites-meningocoques
- https://www.ameli.fr/assure/sante/themes/meningite-aigue/definition-causes-facteurs-favorisants
- https://www.associationpetitange.com/meningites-bacteriennes.html
- https://www.meningitis.ca/fr/Overview
- https://www.who.int/immunization/monitoring_surveillance/burden/vpd/WHO_SurveillanceVaccinePreventable_17_Pneumococcus_French_R1.pdf