U.S. emergency department visits for meningitis, 1993-2008.

OBJECTIVES: Large-scale epidemiologic studies of meningitis in the emergency department (ED) setting are lacking. Using a nationwide sample, the authors determined the frequency of meningitis visits and characterize management.
METHODS: Using National Hospital Ambulatory Medical Care Survey (NHAMCS) data, 1993 through 2008, meningitis diagnoses were studied and national rates were estimated via standard weighting procedures.
RESULTS: Meningitis was diagnosed at 1,048,000 visits (95% confidence interval [CI] = 893,000 to 1,203,000) during 1993 through 2008. This is 66,000 cases annually, or 62 per 100,000 visits, with no change over time (p = 0.20). ED diagnoses were unspecified (60%), viral (31%), bacterial (8%), and fungal (1%) meningitis. Median age was 24 years (interquartile range = 9 to 40 years). While 1.97 times as many adults were diagnosed with meningitis (95% CI = 1.83 to 2.13), meningitis accounted for a similar proportion of visits among children and adults (ratio = 1.33, 95% CI = 0.58 to 2.63). Per population, children were more likely to have a meningitis visit (31 vs. 21 per 100,000; ratio = 1.48, 95% CI =1.003 to 2.10); children aged younger than 3 years had the highest rate (98 per 100,000, 95% CI =63 to 133). Spring and summer visits were 1.25 times as numerous as fall a nd winter (95% CI= 1.15 to 1.36). Third-generation cephalosporins were administered in 42%, analgesics in 19%, and antiemetics in 15% of cases, and 66% were admitted to the hospital (95% CI= 58% to 73%).
CONCLUSIONS: Meningitis is rare, diagnosed at 62 per 100,000 ED visits. Rates have been stable over time. Children are 1.48 times more likely to have a visit for meningitis, although adults make twice as many visits. Absence of consensus guidelines for patients suspected of having viral meningitis but being tested for bacterial meningitis may lead to variability in admission and prescribing decisions.