Urinary tract infections in infants: Comparison between those with conjugated vs unconjugated hyperbilirubinaemia

Aims: The aim was to investigate conjugated and unconjugated hyperbilirubinaemia in association with urinary tract infection (UTI) in young infants. Methods: Fifty infants aged <3 mths who developed prolonged jaundice among 2128 infants with UTI from 1984 to 2004 were enrolled retrospectively. They were divided into conjugated (n=22) and unconjugated (n=28) hyperbilirubinaemia groups and the clinical variables between the two were compared. Results: Compared with the unconjugated group, the conjugated hyperbilirubinaemia group had statistically significantly lower haemoglobin (1.57 vs 1.80 μmol/L), higher aspartate aminotransferase (96 vs 32.5 U/L) and alanine aminotransferase (81.5 vs 16 U/L), were older on admission (48.0 vs 32.5 days), had a longer duration of jaundice before treatment (43.5 vs 30 days) and a higher incidence of E. coli infections (19/22 vs 15/28). The direct/total bilirubin ratio was linearly correlated with duration of jaundice before treatment (p=0.004). The most significant cut-off value for the duration ofjaundice vis-à-vis the type of jaundice was 38 days (p=0.007). Patients who on presentation had had jaundice for >44 days (p=0.007) were unlikely to have unconjugated hyperbilirubinaemia. Conclusions: Infants with UTI may present with unconjugated hyperbilirubinaemia in the early stage. After 6 weeks, it is always conjugated hyperbilirubinaemia and is frequently associated with anaemia, elevated hepatic amino-transferases and E. coli infections.