[Detection of bacteremia in patients discharged from an emergency unit: study of 61 cases]

To know the prevalence, the clinical and microbiological characteristics of bacteremia episodes detected on discharged patients at the emergency unit, as well as the accordance of diagnostics and the predicting factors.

We analysed the cases with bacteria detected on discharged patients during 2 years (1995-1996) in an university hospital. We reported: age, sex isolated organism in blood cultures, bacteremia source, leukocytes count, presence of underlying conditions, and accordance between initial and final diagnosis. We compared the characteristics of the groups with bacteremia without apparent origin and the ones with evident clinical source.

We detected 61 cases, the mean age was 55 years (SD = 21), and 54% were males. The most commonly isolated agent was E. coli (50%). The leukocytes count was higher 10 x 10(9)/l in 15%. The source of bacteremia was: urinary tract infection (54%) no clinical focus (31%), respiratory tract (11%) and biliary duct (3%). The 90% of urinary tract and the 71% of respiratory infections were correctly diagnosed. However only the 5% of bacteremias without apparent source was correctly diagnosed. We found these differences statistically a significant (p < 0.001 and p = 0.002). Underlying conditions were detected in the 84% of cases in bacteremia without apparently source: AIDS (22%), cirrhosis (22%), parenteral drugs addiction (17%) and venous catheter (17%). Comparing both groups, with apparent focus and without it, we found that the presence of underlying condition is the only independent factor which predispose to bacteremia (p = 0.000; RR = 4.6; IC 95% = 1.9-11.8).

The prevalence of bacteremia detected in discharged patients at the emergency unit seems acceptable. However those results suggest that we could decrease the number of patients with bacteremia without apparently source, because this group shows up to be the less successful in diagnosis. In patients with fever and no clinical focus in the emergency unit, it is useful to consider the presence of underlying factors to decide its management.