[Diagnostic usefulness of procalcitonin and C-reactive protein in the Emergency Department for predicting bacterial meningitis in the elderly]. / Rendimiento diagnóstico de la procalcitonina y la proteína C reactiva para predecir meningitis bacteriana en los ancianos en urgencias.

ABSTRACT

OBJETIVES To analyse and compare procalcitonin (PCT) and C-reactive protein (CRP) as tools for detecting bacterial meningitis (BM) in the elderly (>74 years of age). METHODS: A prospective, observational, descriptive, analytical study of 220 consecutive patients aged ≥1year and diagnosed with acute meningitis in an emergency department between September 2009 and July 2014. RESULTS: A total of 220 patients (136 [62%] male) were studied. The mean age was 30±26years, with BM being diagnosed in 17/83 patients from 1 to 14years of age, 32/111 from 15 to 74years of age, and 17/26 patients ≥75years of age. PCT had the highest area under the receiver operating characteristic curve (AUC) (0.972; 95%CI, 0.946-0,998; P<.001) to predict bacterial meningitis. With a cut-off of ≥0.52ng/mL, PCT achieved 93% sensitivity and 86% specificity, and for patients over 75years of age 96% sensitivity and 75% specificity, with the same AUC (0.972). The AUC for CRP was 0.888, and a ≥54,4mg/L cut-off achieved 91% sensitivity and 78% specificity, and for patients over 75years of age an AUC of only 0.514 achieved with 97% sensitivity and 43% specificity. CONCLUSIONS: For all patients with acute meningitis in the emergency department, PCT has a high diagnostic power, outperforming CRP and Leukocytes for detection of bacterial etiology, but CPR is of not useful in the elderly.