Study setting: The present retrospective study was done in Vydehi Hospital, a tertiary care hospital in Bengaluru, India, having an economical, service oriented haemodialysis centre with both nephro-urological services including renal transplantation.

Patient and methods: Medical files of patients with diagnosis of obstructive nephropathy from January 2016 to December 2016 were studied. Data like gender, age, clinical features, laboratory investigations, treatment details, outcome were collected. Factors influencing renal failure and its recovery were analysed.

Descriptive and inferential statistical analysis was carried out in the present study.

Student t-test (two tailed, independent) was used to find the significance between two groups. Levene’s test for homogeneity of variance was performed to assess the homogeneity of variance. Chi-square/Fisher Exact-test was used to find the significance of study parameters between two or more groups.

Significance of values were suggested as: Mild significance (p-value: 0.05<p<0.10), moderate significance (p-value: 0.01<p≤0.05), statistical significance (p≤0.01).

Statistical software: The Statistical software SPSS 18.0 was used for the data analysis. Microsoft word and Excel was used to produce graphs, tables.

Among 107 patients with obstructive nephropathy enrolled, 77 (72%) were male and 30 (28%) were females. Median age of presentation was 46.4 years. Bilateral UTO was present in 58 (54%). Intrinsic causes like stricture urethra, posterior urethral valve, blood clots, prostate and urinary bladder malignancy were seen in 78 (72%). Chronic obstruction (>3 months duration) was seen in 71 (66%). Acute on CKD was seen in 63 (58%), AKI was seen in 44 (41%). Renal transplant patients were 11 (10%). Most common site of obstruction was ureter in 47 (43.9%) [Table/Fig-1]. Among co-morbities, history of UTI, urological surgeries, and diabetes mellitus were seen in 70 (65%), 62 (57.9%), and 62 (57%) of cases respectively. Among the aetiology, commonest cause was blood clots seen in 62 (57%), followed by abdominal lymphadenopathy in 16 (15%) and ureter calculus seen in 14 (13%) cases [Table/Fig-2]. Commonest symptom was pain abdomen in 98 (91.6%) followed by weight loss in 72 (67.3%) and hematuria in 53 (49.5%) cases. Among the complications, UTI was seen in 65 (60%) followed by sepsis in 34 (31.8%) and mineral bone disorder in 13 (12.1%) of cases. Dialysis therapy was needed in 38 (35%). Commonest urological intervention needed was ureter stenting in 37 (34%) followed by percutaneous nephrostomy in 27 (25.2%) and ESWL in 16 (15%) cases. Renal failure recovery was noted in 34 (31%), post obstructive diuresis was noted in 25 (23%), and death in 18 (16%).

Compared to renal failure recovered group, the non recovered group had statistically significant dominant males, were much older, had higher incidence of congenital blocks, acute on CKD, PUJ obstruction, blood clots, abdomen lymphadenopathy, weight loss, abdomen mass, mineral bone disorder, emphysematous APN, lower haemoglobin, leukocytosis, dialysis need and ESWL therapy. It was also noted there was more incidence of bilateral UTO, chronic obstruction, past UTI episodes in non-recovered group though statistically insignificant [Table/Fig-2,3].

Compared to non-recovered group, recovered group had statistically significant block in urethra, younger age group, stricture urethra, cervical cancer, thin urine stream, irritative symptoms, and underwent more frequently internal urethrotomy, Clean Intermittent Catheterisation (CIC), suprapubic cystostomy.

In obstructive uropathy, there is block in urine flow causing urine accumulation which increases pressure in ureter, renal pelvis and calyces [10]. Acute bilateral block could be at urinary bladder, urethra, ureters like prostatomegaly, nephrolithiasis [1]. Chronic block could be due to prostate enlargement and pregnant uterus. Ureter obstruction could be intraluminal or extraluminal. Intraluminal block could be due to stone, blood clot, sloughed papillae [2]. Extraluminal block could be due to enlarged masses placing pressure on urinary tract like enlarged lymphnodes, tumours [2]. Only 21% of obstructive uropathy are due to primary urological malignancy [11]. Obstruction for more than six weeks results in hydronephrosis leading to renal parenchymal damage. Following release of block, brisk diuresis with volume imbalance, dyselectrolytaemia can be noted [12].

In the present study, 77 (72%) cases were males and mean age was 46±17 years, similar to study on obstructive uropathy by Halle MP et al., wherein, 69% patients were male and mean age was 50±18 years [10]. In the study, commonest cause was blood clots probably related to urolithiasis and malignancies seen in 62 (57%), followed by abdominal lymphadenopathy in 16 (15%) and ureter calculus seen in 14 (13%) cases. This finding was unlike urolithiasis (35%), benign prostatic hypertrophy (27%), prostatic cancer (12%), cervical cancer (16%) found in Halle MP et al., study and also unlike to more frequently found congenital urethral valves, pelvi-ureteral junction obstruction in study conducted by EL Imam M study [9,10]. Colicky pain is common feature of obstructive uropathy. It was found in 98 (91.6%) cases in this study, unlike 37% and 48% found in Halle MP et al., El Imam M et al., study respectively [9,10]. Difficulty in micturition initiation, incomplete urine emptying, decrease in urine force, post void dribbling are features of lower urinary tract obstruction like prostatic disease [11]. These features were found in 59 (55.1%) cases in present study unlike 39% and 42% found in El Imam M et al., and Halle MP et al., study respectively [9,10]. Palpable kidneys in hydronephrosis are seen [3]. Palpable urinary bladder is in lower urinary tract obstruction [1]. Palpable flank and abdomen mass were seen in 56 (52.3%) cases in the present study.

Acute and chronic obstruction was noted in 41% and 66% cases respectively, similar to that noted in study conducted by El Imam M [9].

Albuminuria indicates glomerular dysfunction [3,7]. Hematuria is seen in calculi and tumour [3,7]. It was found in 53 (49.5%) cases in the present study. Bacteria and leucocytes in urine indicate UTI like pyelonephritis. UTI was found in 65 (60.5%) cases in the present study, unlike 15% cases found in Halle MP et al., study [10].

Primary urological malignancy was found in 20 (18.6%) cases in the present study, unlike 32% cases found in Halle MP et al., study [10].

Plain radiographs detect 90% of radio-opaque calculi [2,5]. Ultrasound is one of the most common tools to evaluate urinary tract obstruction.

Most important step in management is to relieve the block even in malignancy [1,12]. Bladder Outlet Obstruction (BOO) is managed by placing a foley catheter. If catheterisation fails, a Suprapubic Tube (SPT) is placed. BPH would be treated with surgeries such as Transurethral Resection of the Prostate (TURP). Ureteral stent bypasses the narrowed portion of the ureter to effectively drain the kidney. Urinary diversion like percutaneous nephrostomy tubes is an alternate method to drain the kidneys. In MUO, Metallic stents, ureterolysis and ureteral reimplantation can be considered [2,3]. Stones greater than 7 mm requires interventions like ESWL, ureter stents, Nephrostomy (PCN) [8,12]. Urethral strictures require urethrotomy [2]. In the study, UTO was relieved by ureter stenting, percutaneous nephrostomy, TURP, Transurethral Resection of Bladder Tumour (TURBT), ESWL, urethrotomy in 37 (34.6%), 27 (25.2%), 10 (9.3%), 11 (10.3%), 16 (15%), 10 (9.3%) cases respectively, comparable to urinary drainage done in 45% cases seen in Halle MP et al., study [10]. Dialysis therapy was needed in 38 (35%) comparable to 41% and 23% needing dialysis in Halle MP et al., and El Imam M et al., [9,10]. But renal recovery was less, found in 34 (31%) similar to Halle MP et al., and unlike to EL Imam M study respectively probably related to underlying chronic renal disease on presentation in 71 (66%) and also to majority having chronic morbidities like diabetes mellitus, hypertension, past urolithiasis, UTI. Presence of malignancy increases mortality [9,10,13,14]. Death was seen in 16% due to underlying malignancy, sepsis similar to Halle MP et al., and unlike to 5.56%, 0.3% found in Ibrahim AG and EL Imam M et al., studies respectively [4,9,10]. Hence, early diagnosis of the obstruction and treatment providing relief of the obstruction by using either ureteral stents or PCNs is crucial to preserve kidney function [11].

There are few limitation of the present study as it is a retrospective study, data may be missed. As it a study from a single centre, it may not be generalised. However, it is first study in our centre to describe profile and management of obstructive uropathy which can contribute for better management of such cases in future.

It can be concluded that obstructive uropathy is frequently associated with nephropathy. Blood clots, urolithiasis, malignancies are frequent causes. Prompt relief of block is needed for renal recovery even in chronic cases, though prognosis depends on associated comorbidities.