Renal and urologic problems: management of ureteric obstruction

The challenging management of malignant ureteral obstruction: Analysis of a series of 188 cases

Background

Malignant ureteral obstruction (MUO) is a common condition that complicates the course of advanced malignancies. The aims of this study are to analyze the causes, management, and survival of patients with obstructive nephropathy due to malignant ureteric obstruction and to determine prognostic factors. Furthermore, we studied the complications and outcomes in patients who underwent urinary diversion.

Materials and methods

A retrospective study was conducted on patients with computed tomography-confirmed MUO between January 2016 and November 2020. Demographic, clinical, radiological, laboratory, and management data were collected. Survival curves were estimated using the Kaplan-Meier method, and univariate and multivariate Cox proportional hazards models were used to test the association between parameters and survival.

Results

A total of 188 patients were included. The mean age was 69.01 years (SD, 14.95 years), and the majority (54.8%) were male. The most common mechanism leading to MUO was compression by a pelvic mass (36.9%), and the 3 most frequent tumors causing MUO were prostate (17.6%), bladder (16.5%), and rectal cancer (11.7%).Forty-seven patients (25%) underwent urinary diversion: 23 (48.9%) underwent double-J stenting and 21 (44.7%) underwent percutaneous nephrostomy. The most common reason for urinary diversion was acute kidney injury (53.3%). Recovery of renal function was observed in 55.8% of the patients after urinary diversion. The most frequently identified complications after urinary diversion were urinary tract infection (24.4%), hematuria (17.0%), and urinary sepsis (14.9%). The median survival after hydronephrosis diagnosis was 6.43 months (interquartile range, 1.91-14.81 months). In patients who underwent urinary decompression, the median survival after urinary diversion was 8.67 months (interquartile range, 2.99-17.28 months). In the multivariate analysis, a lower grade of hydronephrosis and cancer cachexia negatively impacted survival.

Conclusions

Cancer patients with MUO have a poor prognosis; therefore, the risk-benefit ratio of urinary diversion should be carefully considered. Cachexia and hydronephrosis grade can be useful in selecting suitable candidates for urinary diversion.

Retrospective Analysis of the Role of Antibiotic Prophylaxis in the Placement and Replacement of Percutaneous Nephrostomy Catheters in Patients with Malignant Ureteral Obstruction

Background: Antibiotic prophylaxis is usually adopted to prevent urinary tract infection (UTI) after nephrostomy catheter placement and replacement. This prophylaxis has been little studied in cancer patients, and its efficacy is uncertain. Objective: To determine the rate of UTI associated with percutaneous nephrostomy catheters placement and replacement and associated risk factors. Methods: This retrospective study collected data from the available medical records. Catheter-related UTI was defined as any diagnosis of UTI based on clinical symptoms recorded in antibiotic prescription charts, and on the results of urine culture collected up to 7 days after percutaneous nephrostomy catheter. The associations between categorical variables were analyzed using Fisher's exact test. The risk factors for UTI were assessed using logistic regression. Results: In the univariate analyses, there was no significant difference in the rate of urinary infection between patients receiving and not receiving antibiotic prophylaxis before percutaneous nephrostomy and after replacement. Conclusion: The results of the present study suggest that the use of antibiotic prophylaxis for managing urinary tract obstruction by percutaneous nephrostomy is not recommended in cancer patients. In contrast, for catheter replacement, antibiotic prophylaxis appears to have a protective effect for UTI.

Cancer Pain Syndromes

Patients with cancer experience many acute and chronic pain syndromes, the identification of which may be helpful in the assessment and treatment of pain. Syndromes are defined by the relationship with the cancer, the pain pathophysiology, and the clinical characteristics of the pain. The most common pain syndromes are directly related to the tumor; bone pain syndromes are most common. Neuropathic pain syndromes may involve cancer-related injury at any level of the peripheral nervous system. Treatment-related pain syndromes may follow any type of antineoplastic therapy. This article reviews the phenomenology of common acute and chronic cancer pain syndromes.

Change of Renal Parenchymal Width in Patients with Unilateral Ureteral Stent: A Bicenter Retrospective Study

PURPOSE

To determine whether kidney sizes were changed after ureteral stents were instilled, and if so, what parameters were significant.

METHODS

Parenchymal width (PW) of 98 patients with unilateral ureteral stents was measured from the coronal view of CT scans for both stented and unstented contralateral kidney. The mean PW and % change of mean PW were calculated before stenting and at the time of last stent change. Estimated glomerular filtrate rate (eGFR) was recorded as well.

RESULTS

The mean duration of ureteral stent indwelled was 15.6 ± 10.2 (mean ± SD) months. The change of mean PW of stented kidneys and unstented contralateral kidneys was -16.9 ± 16.4 (mean ± SD)% and 3.6 ± 10.7%, respectively. eGFR before and at the time of the last stent change did not show significant difference (p = 0.294). Duration of ureteral stent indwelled was found to be inversely related to the % change of mean PW (Spearman's correlation coefficient = -0.291, p < 0.001).

CONCLUSIONS

For unilateral ureteral obstruction, kidney size was decreased over time in spite of indwelling ureteral stent. This finding can be overlooked by clinicians due to compensatory growth of contralateral kidney and resultant normal eGFR.

The use of internal stents in chronic ureteral obstruction

PURPOSE

Despite the lack of a well delineated definition, chronic ureteral obstruction imposes significant quality of life loss, increased pathological morbidity and risk of mortality as well as substantial economic burden. Ureteral stenting serves as an important therapeutic option to alleviate obstruction. Thus, we assessed the recently published literature on chronic ureteral obstruction; treatment options; types, benefits and shortcomings of current ureteral stents; as well as outcomes and complications of chronic ureteral stenting, with the goal of providing concise management guidelines.

MATERIALS AND METHODS

A systemic literature review was performed on Embase™, PubMed®, Cochrane Controlled Trials Register and Google Scholar™ on ureteral obstruction and internal ureteral stents. Relevant reviews, original research articles and their cited references were examined, and a synopsis of original data was generated on a clinically oriented basis.

RESULTS

Chronic ureteral obstruction can be classified into compression that is either intrinsic or extrinsic to the ureteral wall, or obstruction that is of a benign or malignant origin. Patients with malignant ureteral obstruction generally have a poor prognosis and are often difficult to treat. The aim of stenting is to adequately drain the upper urinary tracts while minimizing hospitalization and the negative impact on quality of life. Facing the challenge of chronic ureteral obstruction, novel stents with new compositions, materials, coatings and designs have been developed. Metallic stents are emerging as efficacious and financially viable alternatives. Early stent related complications include iatrogenic injury, stent migration or patient discomfort, while late complications include infection, difficulties with stent exchange, hardware malfunction, infection and stent encrustation.

CONCLUSIONS

Stenting in chronic ureteral obstruction is a complex and challenging problem. Much work is being done in this area and many options are being explored.