Renal Tubular Functions in Patients with Posterior Urethral Valve

Caliskan, Salim/0000-0002-3316-8032; Canpolat, Nur/0000-0002-3420-9756; Kucur, Mine/0000-0002-6579-1996 WOS:000473333700016 Objectives: The aim of this study was to evaluate tubular functions of posterior urethral valve patients with preserved glomerular functions. Methods: A total of 25 children (ages 1 - 18) who underwent surgery for PUV and had an estimated glomerular filtration rate >= 90 mL/min per 1.73 m(2) on long term follow-up and age-matched 25 healthy controls were enrolled. Blood and urine samples were collected to assess electrolyte reabsorption, proteinuria, enzymuria, urine acidification and concentration. Results: Even though microalbumin/creatinine ratio was higher in the patient group [1.00 (1.98) vs 0.31(0.34) mg/gr creatinine, P = 0.005] none of the subjects had enzymuria, overt proteinuria or hyperphosphaturia. Serum bicarbonate levels were lower and urinary pH higher in patients than the controls (23.2 +/- 2.1 VS. 24.6 +/- 1.9 mmol/L, P = 0.028 and 6.24 +/- 0.77 VS. 5.60 +/- 0.64, P = 0.004); furthermore, patients had lower urinary osmolality and density (525 +/- 214 vs. 743 +/- 194 mOsm/L, P = 0.001 and 1011 +/- 5.0 vs. 1016 +/- 6.8, P = 0.005). When patients were compared among themselves according to presence or absence of renal scarring and when patients without renal scars were compared to healthy controls, similar findings persisted. Conclusions: This study showed that during long-term follow-up of posterior urethral valve patients with normal glomerular filtration rates, even though proximal tubular functions do not seem to be impaired, acidification and concentration defects exist indicating distal tubulopathy. Scientific Research Projects Coordination Unit of Istanbul UniversityIstanbul University [17929] This work was supported by Scientific Research Projects Coordination Unit of Istanbul University (project number: 17929).