RELIEF OF URINARY-TRACT OBSTRUCTION IN TUBERCULOSIS TO IMPROVE RENAL-FUNCTION - ANALYSIS OF PREDICTIVE FACTORS

Objective To assess the effect of the relief of obstruction on the ult imate function of the affected renal unit in urinary tuberculosis, and to identify predictors of functional recoverability. Patients and met hods Of a total of 82 patients with urinary tuberculosis presenting ov er 7 years, 38 with evidence of upper tract obstruction were analysed. All patients were assessed with pre-operative excretory urography, ur inary mycobacterial cultures and serum chemistry. Patients with subnor mally functioning kidneys were assessed with baseline renal scans. Pre liminary intervention in the form of JJ stenting or percutaneous nephr ostomy (PCN) was carried out in patients with reasonable renal functio n. Function was reassessed after 4 weeks to detect evidence of improve ment and factors which could affect the outcome were determined. Resul ts Thirty-eight patients had documented upper tract obstruction, of wh om six had bilateral obstruction (total of 44 renal units). Ten renal units were not functioning at presentation, with a mean (so) glomerula r filtration rate (GFR) of 3.0 (5.73) mL/min, and no preliminary inter vention was performed. In the remaining 34, preliminary intervention w as carried out before definitive surgery (JJ stenting in 14, PCN in 15 and PCN followed by antegrade JJ stenting in five); 21 of these renal units were salvaged but 13 were lost despite overcoming the obstructi on. Three of the 13 units deteriorated from having acceptable pre-trea tment GFRs to becoming non-functional. Good renal cortical thickness, a low grade of renal involvement (Semb 1 or 2), the presence of more d istal disease in the form of ureteric stricture and a GFR of >15 mL/mi n were good predictors of renal recovery after diversion. Conclusions The loss of some renal units seems inevitable in patients with urinary tuberculosis, despite advances in chemotherapy. Having pre-operative predictors of renal recovery may ensure optimal patient selection, the reby reducing the number of procedures and economic burden on the pati ent who does not require intervention.