Significance of pyuria in the diagnosis of urinary tract infections in neonates.

OBJECTIVES To determine the significance of pyuria as a predictor of culture proven urinary tract infections (UTI) in neonates and to assess the frequency of urinary tract anomalies in neonates with pyuria. METHODS Prospective study conducted at the neonatal intensive care unit of a tertiary care hospital; (Liaquat National Hospital Karachi) for a period of 4 months from April 2008 to August 2008. One hundred and ten consecutive infants < or = 28 days of age admitted to the NICU of Liaquat National Hospital for medical reasons were included in the study. Information regarding age, gender, antenatal history, birth weight, clinical examination, laboratory findings and outcome were recorded on a questionnaire. Septic work up was performed and urine samples were collected using urethral catheterization. Patients showing any number of white blood cells on microscopy were included and their urine sent for culture. All patients had Ultrasound done during their hospital stay and those patients with any renal abnormality were further investigated with Micturating cyestoretherogram (MCUG) at 6 weeks. RESULTS Out of one hundred and ten patients admitted, thirty five patients showed the presence of pus cells in urine and were included in the study. Of the 35 neonates with pyuria, 71.4% had no growth in urine cultures and 38.2 % neonates with insignificant pyuria (< or = 9 cells in urine) showed a positive culture. The renal ultrasound was normal in 51.4% neonates with pyuria although it was abnormal in 100% of the subjects with higher number of pus cells in urine (> 20 pus cells). CONCLUSION Pyuria is not a useful marker for the diagnosis of culture proven UTI in neonates it cannot be used as an indicator of underlying renal abnormality, though it may have some utility in neonates with > 20 /numerous pus cells.