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Brief Reports Indian Pediatrics 2000;37: 886-889 |
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Urinary Tract Infection in Infants and Young Children with Diarrhea |
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From the Departments of Pediatrics and Microbiology*, Maulana Azad Medical College, New Delhi 110 002, India. Reprint requests: Dr. B. Rath, Professor, Department of Pediatrics, G.T.B. Hospital, Shahdara, Delhi 110 095, India.
Manuscript received: October 26, 1999; Signs and symptoms of urinary tract infection (UTI) are non-specific in infants and do not usually pertain to the genitourinary tract. Diarrhea is a common manifestation of UTI in this period. We therefore wanted to evaluate if this can be used as a high risk index to pick up cases of UTI. Since in developing countries diarrhoea is rampant, demonstration of an association between UTI and diarrhea will be of clinical significance. The present study was undertaken to estimate the prevalence of UTI in children presenting with diarrhea and to identify the clinical cor-relates which may help to identify children with UTI.
One hundred consecutive children aged less than 2 years presenting to Lok Nayak Hospital, New Delhi between May 1995 to November 1995 with diarrhea as the presenting complaint were enrolled as cases. Those who had received antibiotics within 48 hours prior to presentation or had exstrophy of urinary bladder or recto-vesical fistulae were excluded from the study. Urine samples were obtained from all the 100 children by suprapubic aspiration once bladder was full after hydration. Microscopy was done and part of the samples were sent for culture and antibiotic sensitivity testing. Presence of more than 10 pus cells/cumm on microscopic analysis of uncentrifuged urine was taken as significant pyuria(1). UTI was defined as the growth of any number of organisms from the suprapubic urine aspirate. A stool sample was collected from all cases and subjected to microscopy and culture. We defined invasive diarrhea as the presence of >10 pus cells/HPF of stool with or without RBCs. Four patients who were picked up to have UTI on screening and reported for follow up later were subjected to ultrasound examina-tion of the kidney, ureter and bladder and MCU. DTPA renal scan was performed in three of these patients who came for follow up. Statistical analysis of the data obtained was performed using Chi-square and Fischer exact tests. A multivariate analysis was performed using logistic regression.
Of the 100 children with diarrhea, 51 were boys and 49 girls. Eight (8%) in the study group had pathogenic organisms grown in suprapubic urine culture. Seven out of the 8 cases were girls and six of them were between 6-12 months of age. All of them grew Gram negative organisms in urine culture (E. coli - 5, Klebsiella - 2). The only male child with UTI was a neonate who isolated candida repeatedly in his urine culture. He presented with an acute episode of diarrhea and was malnourished. His renal function was normal and he tested HIV negative. He was treated with Amphotericin B after which his diarrhea subsided and he showed satisfactory weight gain. The preva-lence of UTI in girls presenting with diarrhea was 14.2% in contrast to only 1.9% in boys (Table I ). The frequency of UTI in children with recurrent diarrhea (3 or more prior episodes of diarrhea in the preceding 6 months) was 26.3% as compared to 2.4% in those with frequent episodes. Blood cultures of all these 7 girls were sterile. Bacteriuria was seen in 25% children presenting with invasive diarrhea versus 3.7% amongst those with non invasive diarrhoea. Five out of the 8 children with UTI had >10 pus cells/HPF in their stool samples and 2 out of these also had RBCs in their stools. Seven out of the 8 cases were febrile (axillary temperature more than 100°F). UTI was appreciably higher (22.2%) in the cases who were severely dehydrated as compared to those without dehydration (3.7%). The prevalence of UTI amongst those with severe malnutrition (weight less than 60% of NCHS standard for age and sex) was 17.2% as compared to 4.2% amongst those with lesser degree or no malnutrition. All seven girls with UTI had more than 10 pus cells per cumm of uncentrifuged urine. Thus female sex, recurrent diarrhea, fever, severe dehydra-tion, severe malnutrition and invasive stools emerged as significant risk factors. However, multivariate anlaysis by logistic regression revealed only 2 factors - invasive diarrhea and the degree of dehydration to be significant. In only three cases we could isolate the same organism both from urine and stool, organisms being different in other cases. Ultrasound revealed pyonephrosis of the right kidney with pelviureteric junction obstruction in one girl with UTI. In the other 3 cases where it was performed, it was unremarkable. DTPA scanning confirmed the above findings in the child with pyonephrosis and showed bilaterally reduced radiotracer uptake and drainage in another. The latter was found to be hypertensive on follow up. DTPA scan was performed only in 3 children and in the third one it was normal. None of these children demonstrated VUR on MCU. The blood urea and S. creatinine were normal in all children. Table I - Association of Variables with UTI.
The overall prevalence of UTI in children presenting primarily with diarrhea was 8% which compares favourably with the reported prevalence rate of 7.5%(2) and 7%(3). In infants suprapubic aspiration of the urinary bladder has been shown to be a safe and easy method of obtaining urine for diagnosis of UTI(4). We did not note any complication of the procedure in any of our patients. The only male patient with UTI was a neonate who grew Candida in his urine samples repeatedly, rest seven being females, a pattern also observed earlier(5). Isolation of different organisms from stool and urine cultures in five cases out of eight indicate that atleast in these cases the urinary infection was not an ascending one. It seems these were primarily cases of UTI, diarrhea being a manifestation - the so called parenteral diarrhea. In absence of serotyping it is difficult to comment on the causal relationship of even the cases which isolated the same species of organism from both stool and urine. It would have been of interest to perform simultaneous DMSA (dimercapto succinic acid) scans of these children to see if there was renal involvement but due to constraint of resources, the same could not be done. Recurrent episodes of diarrhea had a higher correlation with UTI. The most prominent presenting complaint in a two year old girl with large pyonephrosis was recurrent diarrhea. A high incidence of UTI has been reported in children with persistent diarrhea(6). Invasive diarrhea (more than 10 pus cells and/or RBCs per HPF of stool) emerged as the single most important factor associated with UTI in children presenting with diarrhea. All the girls with bacterial UTI were febrile. There was a significant association between UTI and the degree of malnutrition. Lower secretory levels of IgA at the mucosal surfaces(7) or a subclinical Vitamin A defi-ciency present in the malnourished children may have predisposed them to UTI. Converse-ly, since majority of girls with UTI had a history of recurrent diarrhea, undiagnosed and untreated UTI could have led to the mal-nourished state. UTI is usually caused by Gram negative organisms from the gut by ascending infection. The higher proportion of cases of UTI in children with greater degree of dehydration may be due to oliguria and poor mechanical flushing of the urethra. We found that significant pyuria defined as ³10 pus cells/cu mm of uncentrifuged urine was a quite sensitive (87.5%) and highly specific test (95.6%) to diganose UTI. Thus, though pyuria is a good screening test for UTI, its absence does not rule out the latter. In two out of 8 (25%) of our patients with UTI, there were demonstrable renal lesions. One had a large pyonephrosis of the right kidney and the other had bilaterally poorly functioning kidneys as evidenced by poor radio-isotope uptake and drainage. The renal status of these patients would need monitoring. It seems from the present study that it would be wise to screen febrile infants specially girls with recurrent or invasive diarrhea for UTI. The presence of significant pyuria in microscopic examination of urine can be used as a useful screening tool before sending a sample for urine culture whenever a constraint of resources exists. Contributors: BR coordinated the study; he will act as the guarantor for the paper. RT participated in the data collection and drafted the paper. SKP supervised the microbiological work. SKM and BT helped in critically evaluating and drafting the paper.
Funding:
None.
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