Meningitis: N. meningitidis is the most common cause.

Clinical bottom line (level 2c)

  1. In patients with bacterial meningitis, more than half of the cases were caused by N. meningitidis.
  2. In patients with bacterial meningitis, half had the classic symptoms of fever, stiff neck and impaired consciousness.
  3. Two-thirds of patients had abnormal mental status.
  4. A sixth of patients had complications.
  5. A fifth of patients with bacterial meningitis died.
Sigurdardottir et al: Archives of Internal Medicine 1997; 157: 425-430
Expires November 2003

The study

Setting: community, Iceland

132 patients (aged ?, 55% female) bacterial meningitis or acute meningococcaemia

Excluded if
  • <16 years old
  • had meningitis before 1975 or after 1994



    • Diagnostic test: Positive cerebrospinal fluid and blood cultures were used to diagnose meningitis.
    • Records for patients with the diagnosis of bacterial meningitis or meningicoccal sepsis from hospitals from all over the country were reviewed.

    The evidence


    differential diagnosis number of patients prevalence
    (95% CI)
    Neisseria meningitidis as the cause of infection 74 56.1%
    (47.6% to 64.5%)
    Streptococcus pneumoniae as cause of infection 27 20.5%
    (13.6% to 27.3%)
    Haemophilus influenzae as cause of infection 6 4.50%
    (1.00% to 8.10%)
    Listeria monocytogenes as cause of infection 8 6.10%
    (2.00% to 10.1%)
    presence of the classic three symptoms (fever, neck stiffness and impaired consciousness) 61 51.3%
    (42.3% to 60.2%)
    abnormal mental status 79 66.4%
    (57.9% to 74.9%)
    complications (polyarthritis, hearing loss, oliguric renal failure, temporary paralysis, pericarditis and myocarditis) 19 16.0%
    (9.40% to 22.5%)
    mortality 25 19.7%
    (12.8% to 26.6%)

    • The mean annual incidence over the entire study period was 3.8/100,000.
    • 11/132 CSF culture negative cases may have had viral meningitis - PCR would have been helpful

    Citation

    1. Sigurdardottir B, Bjornsson OM, Jonsdottir KE, et al: Acute bacterial meningitis in adults: A 20-year overview. Archives of Internal Medicine 1997; 157: 425-430
    Contributor: Clare Wotton and Chris Ball, November 1999
    Reviewer: Guy De Bruin

    Clinical Question.
    Patient European or North American population
    Intervention or Exposure how many adults will suffer bacterial meningitis
    Comparison no meningitis
    Outcome in a 20-year period