Prevalence of urinary tract infections in febrile children and role of urine interleukins in diagnosis
Date of Award
Master of Medicine (MMed)
William M. Macharia
Paediatrics and Child Health (East Africa)
Background: Urinary tract infections (UTI) are common in the paediatric age group and can contribute to permanent renal damage. Urine culture takes a minimum of 48 hours, thus delaying treatment in suspect cases. It is also expensive and requires training of laboratory technologists. Early diagnosis is important in prevention of serious sequelae such as hypertension and end stage renal disease. Determination of burden of the problem within a population allows appropriate allocation of diagnostic and management resources. Urine interleukins are postulated to be useful adjuncts in diagnosis of UTI.
Objectives: The primary objective was to determine the prevalence of UTI in febrile children aged 12yrs and below, at theAga KhanUniversityHospital. The secondary objective was to determine the diagnostic utility of urine interleukin 8 (IL-8) and interleukin 6 (IL-6), in detection of UTI using urine culture as the gold standard.
Methodology: This was a cross-sectional survey conducted at the Aga Khan University Hospital,Nairobi between March and August 2010. All patients ≤12 years of age with fever presenting at theAga KhanUniversityHospital were enrolled .The minimum sample size was 92. Consecutive sampling was carried out until sample size was achieved. Urine samples were collected as mid stream for toilet trained children and urethral catheterization for children ≤two years of age after consent was obtained.
Prevalence of UTIs was determined and a 2 by 2 contingency table was used in the calculation of the diagnostic utility of urine IL-6 and IL-8.ROC curves were plotted to illustrate sensitivity and specificity of IL-6 & 8 cut offs.
Results: A total of 98 patients were enrolled, 52% were male and the mean age of patients recruited was 57.6 months (range 0-144 months). Prevalence of UTI was 13.3% (95%CI 7.95-21.4) and 69% of patients with UTI were female. The sensitivity, specificity, positive and negative predictive values of IL-6 were 50% (18.7-81.3%), 69.2% (57.8-79.2%), 17.2% (5.85-35.8%) and 91.5% (81.3-97.2%) while for IL-8 they were 20% (2.52-55.6%), 98.7% (93.1-100%), 66.7% (9.43-99.2%) and 90.6% (82.3-95.8%) respectively. Likelihood ratio for urine IL-6 was 1.6 at >1.8pg/ml (.794-3.24) and 15.6 (1.55-157) for IL-8 at >200pg/ml. Confidence intervals (95%) are shown in brackets.
Conclusion: The overall prevalence of UTI in febrile children at the Aga Khan University Hospital, Nairobi was noted to be similar to that reported in Kenya and higher than that in developed countries. The diagnostic utility of urine interleukins was found to be poor and unsuitable as screening tests but useful adjuncts in ruling out UTI. Although a larger study with enough power to determine actual diagnostic utility of IL6/8 would be most appropriate, it is unlikely that a stronger case can be made for these more expensive tests compared to the basic cheaper tests with higher diagnostic utility.
Rerimoi, A. J. (2010). Prevalence of urinary tract infections in febrile children and role of urine interleukins in diagnosis (Unpublished master's dissertation). Aga Khan University, East Africa.
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