The incidence of bacteriuria and pyuria in Peruvian children with malnutrition

The prevalence and risk of urinary tract infection in malnourished children: a systematic review and meta-analysis

BACKGROUND

There are vast differences in prevalence rates of urinary tract infection (UTI) reported among malnourished children globally. We conducted a systematic review and meta-analysis to provide estimates of pooled prevalence of UTI among these children and combined UTI risk in comparison with their well-nourished counterparts.

METHODS

We systematically searched electronic databases (MEDLINE, EMBASE, ISI Web of Science and African Journals Online; date of the last search: 22 December 2018) for studies reporting either the prevalence of UTI in malnourished children or parallel healthy controls. Eligible primary studies were observational studies of children in English Language reporting UTI prevalence with background malnutrition or with enough data to compute these estimates, as well as studies which reported at the same time UTI prevalence in healthy controls. We synthesized published prevalence rates or associations (odds ratios [OR]) between malnutrition and UTI and their 95% confidence intervals (CI) using random effects meta-regression and explored potential heterogeneity determinants using meta-regression analysis. This review is registered with PROSPERO, number- CRD42018084765.

RESULTS

We included 26 cross-sectional and 8 case-control studies reporting on UTI prevalence in malnourished children, and in malnourished children vs. healthy controls, respectively. The pooled prevalence of UTI in 3294 malnourished children was 17% (95% CI, 13, 21%). Heterogeneity was high (I2 = 87.6%; Tau2 = 0.06) as studies varied in their sample size, degree of malnutrition, and study period. Multivariate meta-regression model, including these factors, explained 34.6% of the between-study variance. Pooled OR of UTI in association with malnutrition in 2051 children (1052 malnourished children vs. 999 controls) was 2.34 (95% CI, 1.15, 3.34), with lower between-study heterogeneity (I2 = 53.6%; Tau2 = 0.47).

CONCLUSIONS

UTI is more prevalent in malnourished children than in their well-nourished counterparts. Screening and treatment for UTI should be incorporated in the management protocol of malnourished children to improve disease outcomes.

Absolute and relative accuracy of rapid urine tests for urinary tract infection in children: a meta-analysis

Rapid urine tests, such as microscopy, for bacteria and white cells, and dipsticks, for leucocyte esterase and nitrites, are often used in children that are unwell to guide early diagnosis and treatment of urinary tract infection. We aimed to establish whether these tests were sufficiently sensitive to avoid urine culture in children with negative results and to compare the accuracy of dipsticks with microscopy. Medline, Embase, and reference lists were searched. Studies were included if urine culture results were compared with rapid tests in children. Data were analysed to obtain absolute and relative accuracy estimates. Data from 95 studies in 95 703 children were analysed. Summary estimates for sensitivity and specificity for microscopy for Gram-stained bacteria were 91% (95% CI 80-96) and 96% (92-98), for unstained bacteria were 88% (75-94) and 92% (84-96), for urine white cells were 74% (67-80) and 86% (82-90), for leucocyte esterase or nitrite positive dipstick were 88% (82-91) and 79% (69-87), and for nitrite-only positive dipstick were 49% (41-57) and 98% (96-99). Microscopy for bacteria with Gram stain had higher accuracy than other laboratory tests with relative diagnostic odds ratio compared with bacteria without Gram stain of 8.7 (95% CI 1.8-41.1), white cells of 14.5 (4.7-44.4), and nitrite of 22.0 (0.7-746.3). Microscopy for white cells should not be used for the diagnosis of urinary tract infection because its accuracy is no better than that of dipstick, laboratory facilities are needed, and results are delayed. Rapid tests are negative in around 10% of children with a urinary tract infection and cannot replace urine culture. If resources allow, microscopy with Gram stain should be the single rapid test used.

Bacteriuria and urinary tract infections in malnourished children

We prospectively examined the incidence of bacteriuria in malnourished patients between 6 months and 5 years of age. For each patient, a normally nourished control matched for age, sex, and presence of fever and diarrhea was included. Of 112 patients (65 boys), 55 had moderate and 57 had severe malnutrition; 43 had diarrhea and 35 had fever. Clean-catch and suprapubic urine specimens were examined microscopically and cultured. Significant bacteriuria was found in 17 (15.2%) malnourished and 2 (1.8%) control subjects ( P<0.01). The incidence of bacteriuria in malnourished and normally nourished subjects with fever was 28.6% and 5.7%, respectively ( P<0.05). The risk of bacteriuria increased significantly with the severity of malnutrition and in patients with diarrhea. Bacteriuria was associated with symptoms (70.6%) and elevated levels of acute-phase reactants (88.2%), indicating the presence of urinary tract infections (UTI) rather than asymptomatic colonization. Our observations show that malnourished children, particularly those with fever, are at risk for UTI. Urinalysis is useful for screening for UTI in these subjects. Urine culture should be performed in patients showing an abnormal urinalysis, and if the likelihood of detecting bacteriuria is high (as in patients with fever or diarrhea). Significant bacteriuria in malnourished subjects should be treated with appropriate antimicrobials.

Bacteriuria in children attending a primary health care clinic: a prospective study of catheter stream urine samples

Urinary tract infection (UTI) in infancy and childhood has received scant attention at primary health care (PHC) level, rarely featuring as one of the common diseases. In a prospective study conducted at a PHC clinic, 16 of 94 children (17%) from whom urine was collected by strict aseptic catheterization had bacteriuria (BU). Twelve of these had associated leucocyturia (> 5 WBC/HPF). The median age of those with BU was 9 months (range 1-30 months). BU rarely occurred in isolation (6%), but was most often detected in association with acute respiratory infection (43%) and acute diarrhoea (19%). No association of BU with mild malnutrition was detected in the 50% of children who were underweight for age. Gram-negative pathogens accounted for 14 cases (87.5%). These pathogens were resistant to commonly recommended antibiotics for UTI. Only five cases of BU returned for follow-up at 3 months; no abnormalities were detected on repeat catheter urine samples, urinary tract ultrasonography, voiding cystourethrogram and DMSA studies in them. From these and other findings we conclude that BU is probably often present in young children with common diseases attending PHC centres in developing countries. Further studies are required to establish exactly the role these pathogens play in the pathogenesis of UTI.

Urinary tract infection in malnourished rural African children

During an 8-month period from 1 September 1992 to 30 April 1993, 134 children less than 5 years of age admitted with all grades of malnutrition to a rural hospital were investigated for urinary tract infection. Thirty-five (26.1%) had proven infection. Incidence rates amongst malnutrition categories did not vary significantly. Antibiotic sensitivities with reference to ongoing surveillance and antimicrobial usage is discussed. The value of dipstick screening tests was analysed for predictability and found to be an unreliable alternative to traditional culture techniques. This study emphasizes that urinary tract infection in malnutrition is common and should be routinely investigated.

Urine testing in young febrile children: a risk-benefit analysis

OBJECTIVE

To assess the relative risks and benefits of 10 potential urine testing strategies (compared with no testing) involving urinalysis and urine culture for children aged 3 to 24 months with fever but no focus of bacterial infection.

DESIGN

Decision analysis based on the literature. The 10 testing strategies consist of five pairs; within each pair of strategies, one calls for urinalysis and urine culture of a clean-voided (bag) specimen, and urine culture, and in the other, the urine specimen is sent for culture only if the result of the urinalysis is abnormal. The five pairs differ in selectivity for testing: all children, girls only, temperature > or = 39 degrees C only, fever only (no respiratory or gastrointestinal symptoms), or temperature > or = 40 degrees C only. The results of the decision analysis are expressed as the preventive fraction (the proportion of cases prevented) for end-stage renal disease (ESRD) and hypertension, and as two risk/benefit (RB) ratios: the number of children tested per case of ESRD prevented (RB1), and the number of children with false-positive diagnosis and treatment of urinary tract infection per case of ESRD prevented (RB2).

RESULTS

On the basis of the available evidence, none of the testing strategies succeeds in preventing the majority of cases of ESRD and hypertension (preventive fraction = 0.10 to 0.50), and all are associated with high ratios of children tested (RB1 = 4167 to 12,500) and false-positive diagnosis and treatment (RB2 = 563 to 1800) per case of ESRD prevented. A strategy of combined urinalysis and urine culture in children with temperature > or = 39 degrees C is associated with the most favorable RB profile: preventive fraction = 0.45, RB1 = 5556; RB2 = 776. Sensitivity analyses indicate that the relative ranking of the strategies is relatively robust in regard to alterations in the estimates of the sensitivity or specificity of the urinalysis, the relative risk of renal scarring associated with delayed diagnosis and treatment, and the risk of scarring-induced hypertension or ESRD.

CONCLUSIONS

Up to 50% of the long-term sequelae of occult urinary tract infections in young febrile children appear preventable by urine testing, but even the most favorable strategies require testing of thousands of children, and unnecessarily treating hundreds, for every case prevented. Our analysis reveals those strategies with more favorable RB profiles and emphasizes the need for rapid and convenient urine tests with much higher sensitivity and specificity or the need for less aggressive management strategies for febrile infants and young children with urinary tract infection.

Evaluation of urinary tract infection in malnourished black children

Urinary tract infection (UTI) is a well recognized complication in malnourished children. The need to investigate these patients for underlying renal pathology has not been clearly defined. Seventy-five children with malnutrition were evaluated for UTI by culture of urine obtained suprapubically prior to antibiotic therapy. All patients with UTI were investigated with renal ultrasonography, intravenous pyelography (IVP) and voiding cystourethrography (VCU). Haemoglobin, white cell count, serum urea, creatinine and electrolytes were determined in all the children. The mean age of the children was 15.5 months (range 3-60 months). UTI was diagnosed in 26 (34.7%), of whom 21 (81%) were boys. The overall prevalence of UTI in those with kwashiorkor/marasmic kwashiorkor was 42%. Escherichia coli was the organism most commonly cultured (84.6%). Renal sonography, IVP and VCU were normal in all infected cases and vesicoureteric reflux was not detected in any. This study confirms the high prevalence of UTI in malnourished children. As no anatomical abnormalities were demonstrated in the patients with UTI, imaging of the renal tract other than real sonography does not appear to be indicated in the malnourished child in a first episode of UTI with normal renal function.