Early versus late diagnosis in community-acquired bacterial meningitis: A retrospective cohort study

OBJECTIVES: To examine clinical characteristics and outcome of patients with late diagnosis of community-acquired bacterial meningitis (CABM).

METHODS: We conducted a chart review of all adults with proven CABM in three centres in Denmark from 1998 through 2014. Patients were categorised as 1) early diagnosis of CABM immediately on admission or 2) late diagnosis if CABM was not listed in referral or admission records and neither lumbar puncture nor antibiotic therapy for meningitis was considered immediately on admission. We used modified Poisson regression analysis to compute adjusted relative risks (adj. RRs) with 95% confidence intervals (CIs) for predictors of late diagnosis and in-hospital mortality.

RESULTS: A total of 113/358 (32%) patients were categorised as late diagnosis demonstrating a variety of tentative diagnoses of which 81/113 (72%) were non-infectious. We observed several statistical significant differences baseline differences (p<0.05) in patients with late vs. early diagnosis including age above 65 years (56/113, 50% vs. 67/245, 27%), neck stiffness (35/97, 36% vs. 183/234, 78%), concomitant pneumonia (26/113, 23% vs. 26/245, 11%), and meningococcal meningitis (6/113, 5% vs. 52/245, 21%). These variables remained statistically significant in multivariate analysis. Moreover, late diagnosis was associated with increased in-hospital mortality (41/113, 36% vs. 43/245, 18%; adj. RR=1.7, CI 1.2-2.5).

CONCLUSIONS: Late diagnosis of CABM was common and patients were admitted with mostly non-infectious diagnoses. Absence of neck stiffness did not rule out CABM and special attention should be given to patients with pneumonia and elderly. Late diagnosis was associated with incorrect patient management and increased mortality.