Jaundice as an early diagnostic sign of urinary tract infection in infancy

Urinary tract infections (UTIs) are a common clinical problem in febrile infants younger than 8 weeks old, with a prevalence between 5% and 11%. Previous studies have noted that jaundice may be one of the first signs of a bacterial infection in infants. Our goal was to determine the incidence of UTIs in asymptomatic, jaundiced infants younger than 8 weeks old and to determine which historical and laboratory parameters are associated with UTIs.

We prospectively evaluated asymptomatic, jaundiced infants younger than 8 weeks old for evidence of a UTI (defined as >10 000 colony-forming units per milliliter of a single pathogen, obtained by bladder catheterization). A serum fractionated bilirubin level was obtained on all study patients. Detailed questionnaires were completed, which included demographic information, prenatal, intrapartum, and postnatal events.

Twelve (7.5%) of 160 infants had a UTI (95% confidence interval: 3.9%-12.7%). Isolated organisms included Escherichia coli, Enterobacter cloacae, Enterococcus, Klebsiella pneumoniae, group B Streptococcus, Streptococcus viridans, and Staphylococcus aureus. Patients with the onset of jaundice after 8 days of age had a higher incidence of UTI, 6 (50%) of 12 infants in the positive culture group, versus 15 (10%) of 148 infants in the negative culture group. Abnormal urinalysis and microscopy results were noted in 5 (42%) of 12 infants with a UTI, and 6 (55%) of 11 infants had abnormal renal ultrasound results.

A UTI was found in 7.5% of asymptomatic, afebrile, jaundiced infants younger than 8 weeks old. In addition, infants with the onset of jaundice after 8 days of age or patients with an elevated conjugated bilirubin fraction were more likely to have a UTI. Therefore, we recommend that testing for a UTI be included as part of the evaluation in asymptomatic, jaundiced infants presenting to the emergency department.