We aimed to determine the incidence of occult bacteremia in children with fever without apparent focus between 3-36 months, and to evaluate acute phase reactants related to the increased probability of having a positive blood culture. A retrospective cohort study was conducted in the Pediatric Emergency Department of Ankara University between 2010 and 2017. The study group consisted of 3 to 36 months old children who were healthy and had fever without apparent focus. Patients with bacteremia were compared with patients of similar age and sex who had no fever and presented with fever at the same time. Bacteremia was detected in 41 children. Streptococcus pneumoniae was the most common agent (31.7%), Salmonella spp. (21.9%), Escherichia coli (19.5%), Staphylococcus aureus (9.7%), Moraxella catarrhalis (7.3%) Group A was followed by β hemolytic streptococcus (2.4%), Klebsiella spp. (2.4%), Neisseria meningitidis (2.4%) and Proteus mirabilis (2.4%). The mean white blood cell (WBC) count was 13,497±8,113/mm3 in the bacteremia group and 10,664±5,296/mm3 in the control group (p=0.125). The absolute neutrophil covent (ANC) was an average of 8,628±6,675/mm3 in the bacteremia group, and 5,575±4,020/mm3 in the control group (p=0.011). In the bacteremia group, CRP was found to be 59.6±66.0 mg/L on average and 18.16±31.31 mg/L (p<0.001) in the control group. Erythrocyte sedimentation rate (ESR) was 34.9±21.7 mm/h in the bacteremia group and 22.2±21.0 mm/h in the control group (p=0.004). Bacteremia was detected in 14 (35%) of 40 cases with a fever of ≥38°C and in 27 (64.3%) of 42 cases with a fever ≥39°C (p = 0.015). Bacteremia was seen in 12 (92.3%) of the 13 cases with pyuria and 26 (44%) of 59 cases without pyuria (p=0.004). According to the findings of this study, in cases where CRP, ANC, ESR elevation, pyuria and fever are detected ≥39°C, the probability of bacteremia is high. However, in other studies, parameters such as high WBC, WBC ≥15,000/mm³ and fever ≥39°C association, ANC ≥10,000/mm3, which were found to be useful in predicting severe bacterial infection, are also important. In our study, the relationship between WBC <5,000/mm3, hemoglobin level, thrombocyte and lymphocyte counts, stool leukocyte, chest radiography and bacteremia was also evaluated, but no significant relationship was found.

Keywords: fever, fever without a focus, bacteremia, severe bacterial infection, child