The utility of platelet indices in diagnosis of urinary tract infection

Abstract

Background: Urinary tract infection (UTI) is one of the most common infections in children and may lead to serious morbidity (such as chronic pyelonephritis and renal scarring) and mortality. Thus, early, appropriate, reliable diagnosis in children is mandatory and prompt antimicrobial treatment is required to minimize renal scarring and progressive kidney damage. When the diagnosis is underestimation may lead toshortterm or long-term complication while when the diagnosis is overestimation may lead to use over and unnecessary investigation and work up and invasive proceduresfor diagnosis even in healthy children. Aim of the study: 1. The platelet indices could be used as an index for immediate diagnosis and management of UTI even the results of urine culture is not available. 2. What is the relation between the changes in platelet indices with the type of micro-organism (gram +ve or gram -ve) for proper choice of antibacterial therapy? Methods: This study (prospective case–control)is done in Karbala teaching hospital for children, holly Karbala, Iraq. In the period from1, March to 31, December 2018.The study population consist of 105 children with culture proved UTI and 105 non UTI cases as a control,their age ranging from fifteen days to fourteen years’ old. Children with hematological and non-hematological diseases affecting platelet indices were excluded. Platelet indices were taken including platelet count, mean platelet volume (MPV) and platelet distribution width (PDW) which statistically analyzed. Results: A total of 105 children with culture proved UTI, 53 (50.5%) female and 52 (49.5%) male and 105 non UTI cases as control, 58 (55.2%) female and 47 (44.8%) male were enrolled in this study with no significant differences between both groups in demographic variables. Regarding the results of culture, 64 (61%) patients had gram negative rods while the remaining 41 (39%) patients had gram positive cocci and the main causative agent was E. Coli in 49.5% of total cases.The comparison of hematological parameters, revealed that mean hemoglobin level was significantly lower than that of controls, while platelet count, MPV, PDW, white blood cells and (WBC), were significantly higher in UTI cases than controls, in all comparisons, P<0.05. Furthermore, the mean platelet count, MPV, PDW, WBC and C-reactive protein (CRP) is higher with significant value in gram +ve subgroup than that of gram -ve subgroup, in all comparisons, P<0.05, while Hemoglobin level show insignificantvariation in both subgroups, P>0.05. Further analysis revealed that count, MPV, PDW, WBC and C-reactive protein (CRP) were good predictors and can differentiate between gram positive and gram negative subgroups with relative difference in validity of these parameters. By comparison of different markers validities, MPV and PDW were better than the platelet counts and CRP with regards to the balance between sensitivity and specificity, where the latter two parameters had lower specificity. Conclusion: Platelets indices were good predictors of UTI and can differentiate between types of organism in term of gram positive or gram negative. Platelets counts, MPV, and PDW had good sensitivity, specificity and accuracy in prediction and differentiation.