Meningitis, Bacterial

Descriptive text is not available for this image BASICS

DESCRIPTION

Bacterial infection of the meninges resulting in inflammation, pain, and systemic illness.

EPIDEMIOLOGY

Predominant age: neonates, infants, and elderly; Predominant sex: male = female

Incidence

  • Varies by age and pathogen
  • Overall incidence of bacterial meningitis in 2014 was 0.9/100,000
    • 18 to 34 years: 0.66/100,000
    • 35 to 49 years: 0.95/100,000
    • 50 to 64 years: 1.73/100,000
    • ≥65 years: 1.92/100,000
    • Group B Streptococcus: 0.306/100,000. Neisseria meningitidis: 0.123/100,00
    • Haemophilus influenzae type B: 0.058/100,000

Prevalence

15,000 to 25,000 cases occur annually in the United States.

ETIOLOGY AND PATHOPHYSIOLOGY

Community-acquired bacterial meningitis is most commonly due to Streptococcus pneumoniae and N. meningitidis. Nosocomial or postsurgical meningitis occurs after manipulation of the central nervous system (CNS); newborns (<2 months): group B Streptococcus, Escherichia coli, L. monocytogenes; infants and children: S. pneumoniae, N. meningitidis, H. influenzae; adolescents and young adults: N. meningitidis, S. pneumoniae; immunocompromised adults: S. pneumoniae, L. monocytogenes, gram-negative bacilli such as Pseudomonas aeruginosa; mixed bacterial infection in <1% of cases; older adults: S. pneumoniae, N. meningitidis, L. monocytogenes; gram-negative bacilli: E. coli, Klebsiella, Enterobacter, P. aeruginosa

Genetics

Some Native American populations appear to have genetic susceptibility to invasive disease.

RISK FACTORS

Those at risk include: Household or close contacts of case patients; immunocompromised (including HIV, asplenia, or patients taking eculizumab, ravulizumab), alcohol use disorder, diabetes, pregnancy, elderly; neurosurgical procedure/head injury, close living quarters (dormitories or military barracks), and work exposures; neonates: prematurity, low birth weight, premature rupture of membranes, maternal peripartum infection, and urinary tract abnormalities, untreated maternal group B Streptococcus; anatomical abnormality of nasopharynx and subarachnoid space (congenital, trauma), dural fistula; parameningeal source: otitis, sinusitis, mastoiditis, skull fracture; complement deficiencies, properdin, factor H, and factor D

GENERAL PREVENTION

Vaccines play a crucial part in meningitis and overall disease prevention. Meningitis caused by H. influenzae type B has decreased following routine vaccination. Meningococcal conjugate vaccine (MenACWY) with booster has decreased Meningococcal disease 4-fold. The pneumococcal conjugate vaccine has decreased the incidence rates of S. pneumoniae by 41–97% in children and older adults. Chemoprophylaxis is recommended for close contacts of meningococcal meningitis. Aseptic techniques for head wounds, skull fractures, and surgeries that could infect the cerebrospinal fluid cerebrospinal fluid (CSF).

COMMONLY ASSOCIATED CONDITIONS

Alcohol use disorder, elderly, infancy, diabetes mellitus, multiple myeloma, head trauma, immunocompromised, coma, seizures, sepsis, sinusitis, CSF shunt/drain, asplenia, cancer, sickle cell anemia

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