Catheter test: A reliable alternative to assess adequacy of bladder management in patients of PUV in developing countries

Abstract

Introduction: Following posterior urethral valve ablation, persisting bladder dysfunction can lead to lack of improvement or worsening of hydronephrosis and as well, to lack of improvement or even worsening renal function. On the other hand, managing bladder dysfunction offers the possibility of lessening both the degree of hydronephrosis and the level of serum creatinine. As we have no available urodynamics we feel impelled to find other means of diagnosing and managing abnormal bladder dynamics in these boys. We wanted to determine if a short course of continuous bladder drainage would be an effective means of lowering abnormal serum creatinine levels. Based on an assumption that most bladders following valve ablation, especially in those boys with a persistently elevated serum creatinine post valve ablation, have some form of dysfunction, we wanted to determine if a short course of continuous catheter drainage could improve these abnormal serum creatinine levels.

Methods: The study was conducted over a 3year period and included all children up to 3 years of age who had higher age-appropriate nadir serum creatinine, 3 months post valve ablation. Patients were followed up at 1 week, 2 month and 3-month post valve ablation. On third follow-up visit patients with an elevated serum creatinine level were subjected to continuous bladder drainage (catheter test) for 5 days and serum creatinine level was recorded at the end of 5th day. Enforced bladder management which included dose titration of anti-muscaranic drugs and clean intermittent catheterization (CIC) with or without nocturnal catheter drainage (NOC) was instituted for next 3 months. Serum creatinine was determined at the end of the 3 month period and compared with prior values.

Results: A total of 21 patients were included in the study. The mean age of the children at the time of valve ablation was 6.97 ± 4.38 months. There was a significant fall in serum creatinine from 0.64 ± 0.12 mg/dl pre 5 days of drainage to 0.48 ± 0.10 at the end of the 5 day period (p = 0.024) along with a significant rise in GFR (p = 0.001). Following 3 months of enforced bladder management, there was a very mild rise in creatinine to 0.51, a normal age adjusted value.

Discussion: The study demonstrates the importance of early diagnosis of bladder dysfunction in boys with an elevated serum creatinine levels post valve ablation. Elevated nadir serum creatinine 3 months post ablation seems to be a useful indicator of possible bladder dysfunction; lowering of serum creatinine following a 5 day trial of continuous bladder drainage confirms this diagnosis. However, the lack of availability of urodynamic testing leaves the specific type of bladder dysfunction undiagnosed.

Conclusion: Lowering of serum creatinine following a 5-day trial of continuous bladder drainage can be used as a rough indicator of existing bladder dysfunction in boys with a history of PUV and should be used in countries without urodynamic equipment as an indicator for at least a 3 month trial of enforced bladder management.

Keywords: Bladder dysfunction; Posterior urethral valves; Serum creatinine; eGFR.