Prediction of renal recovery in hydronephrotic kidneys

Urine produced by obstructed kidneys was analysed in 35 cases. In the absence of infection by urea splitting organisms, estimation of urinary pH of hydroephrotic kidneys was found to be a reliable method for determination of recovery potential. After removal of obstruction, radiological recovery was almost complete when the pH was lower than 6. Obstructed kidneys producing urine with a pH between 6-7.1 showed only partial radiological recovery after surgical correction. All kidneys that showed no function on IV urography and those found at operation to possess only a very thin shell of cortex to justify nephrectomy were found to have urinary pH near 7.3 or more, implying inability of those kidneys to acidify urine. Urinary specific gravity and sodium concentration of obstructed kidneys were not reliable in prediction of renal recovery.