bacterial meningitis

Last edited 04/2024

Bacterial meningitis is the inflammation of the meninges resulting in high mortality and morbidity throughout the world (1).

• it is a medical, neurologic, and neurosurgical emergency that needs a multidisciplinary approach (2)
• detected early, it is potentially treatable, but even with optimal intervention there is a mortality of 10 or 20%.

With the emergence of conjugated vaccines, the burden of bacterial meningitis has reduced dramatically in children and as a result community-acquired bacterial meningitis has become a disease that affects more adults than children (1).

The causative agent of bacterial meningitis varies according to the age of the patient and predisposing factors (1)

The main bacteria that cause meningitis in adults, children and babies over 3 months old are Neisseria meningitidis (meningococcus) and Streptococcus pneumoniae (pneumococcus) (3)

• these 2 bacteria normally spread by person-to-person droplet transmission (for example, sneezing)
• Haemophilus influenzae type b used to be another common cause, but since vaccination started it is now rare
• in babies under 3 months old, group B Streptococcus, Escherichia coli and other coliforms are common
• Listeria monocytogenes is very rare, but occasionally causes meningitis in older people, very young children, and in people with other risk factors

Be on heightened alert to the possibility of bacterial meningitis (including meningococcal meningitis) in people with any of these risk factors (3):

• missed relevant immunisations, such as meningococcal, Haemophilus influenzae type b (Hib) or pneumococcal vaccines
• reduced or absent spleen function
• congenital complement deficiency or acquired inhibition
• they are a student in further or higher education, particularly if they are in large shared accommodation (such as halls of residence)
• a family history of meningococcal disease
• they have been in contact with someone with Hib disease or meningococcal disease, or have been in an area with an outbreak of meningococcal disease
• a previous episode of bacterial meningitis or meningococcal disease
• a cerebrospinal fluid leak
• a cochlear implant

Reference:

• (1) van de Beek D et al. ESCMID guideline: diagnosis and treatment of acute bacterial meningitis. Clin Microbiol Infect. 2016;22 Suppl 3:S37-62.
• (2) van de Beek D, et al. Community-Acquired Bacterial Meningitis in Adults. N Engl J Med 2006;354:44
• (3) NICE (March 2024). Meningitis (bacterial) and meningococcal septicaemia in under 16s: recognition, diagnosis and management.