Acute kidney injury due to bilateral ureteral obstruction in children

Post-obstructive Acute Kidney Injury Due to a Retroperitoneal Mass

This case report discusses post-obstructive acute kidney injury (AKI) in a 26-year-old woman with neurofibromatosis type 1 (NF1) and uterine fibroids. The patient's AKI was diagnosed through elevated creatinine and blood urea nitrogen (BUN) levels and confirmed by transabdominal ultrasound and computed tomography (CT) scan, which revealed severe bilateral ureterohydronephrosis. The patient underwent fluoroscopic and sonographic bilateral nephrostomy tube placement, which significantly improved renal function. An exploratory laparotomy and superficial mass biopsy indicated a retroperitoneal tumor consisting of fibroadipose and muscular tissue with focal suppurative inflammation. The patient's renal function normalized by discharge. This case underscores the importance of early recognition, radiological evaluation, and timely intervention in managing AKI secondary to obstructive uropathy and calls for further research on optimal management strategies for AKI secondary to primary retroperitoneal masses.

Comparison of absolute renal uptake by using Tc-99m MAG-3 and Tc-99m DMSA

PURPOSE

The purpose of this study is to compare the value of absolute renal uptake (ARU %) in patients by using Tc-99m MAG-3 and Tc-99m DMSA scan.

MATERIAL AND METHODS

Absolute renal uptake is calculated using Tc-99m MAG-3 and Tc-99m DMSA in renal scintigraphy, Itoh and Tauex kidney depth methods used, respectively. n = 40 adult patients of both genders were included. All patients underwent Tc-99m MAG-3 and Tc-99m DMSA, respectively.

RESULTS

The values of ARU (%) were calculated separately in selected patients n = 40, (left = 17, right = 23 normal functioning kidneys) by MAG-3 and DMSA. Absolute renal uptake (%) of Tc-99m MAG-3 in left kidneys was found to be 15.2 ± 3.4, with spilt renal function 79.2 ± 14.7 and ARU (%) in right kidneys 16.2 ± 3.4 with spilt renal function 77.5 ± 19. Absolute renal uptake of Tc-99m DMSA in left kidneys was 17.5 ± 3.2 and in right kidneys 17.9 ± 4.5 with spilt renal function 81.8 ± 10.7 and 79.3 ± 13.8 for left and right kidney, respectively. Statistical analysis showed strong Pearson correlation.

CONCLUSION

Absolute renal uptake % was found to be more reliable in cases of bilateral compromised kidneys. ARU (%) calculated by Tc-99m MAG-3 solely can be used as predictor of renal function. The use of Tc-99m MAG-3 has more advantages than Tc-99m DMSA alone in renal scintigraphy as dynamic scintigraphy gives less radiation burden to patient, more information regarding renal function, and shorter stay time at hospital in comparison to static renal imaging. SRF % is less reliable than ARU (%).

Antimicrobial and Antiproliferative Coatings for Stents in Veterinary Medicine-State of the Art and Perspectives

Microbial colonization in veterinary stents poses a significant and concerning issue in veterinary medicine. Over time, these pathogens, particularly bacteria, can colonize the stent surfaces, leading to various complications. Two weeks following the stent insertion procedure, the colonization becomes observable, with the aggressiveness of bacterial growth directly correlating with the duration of stent placement. Such microbial colonization can result in infections and inflammations, compromising the stent's efficacy and, subsequently, the animal patient's overall well-being. Managing and mitigating the impact of these pathogens on veterinary stents is a crucial challenge that veterinarians and researchers are actively addressing to ensure the successful treatment and recovery of their animal patients. In addition, irritation of the tissue in the form of an inserted stent can lead to overgrowth of granulation tissue, leading to the closure of the stent lumen, as is most often the case in the trachea. Such serious complications after stent placement require improvements in the procedures used to date. In this review, antibacterial or antibiofilm strategies for several stents used in veterinary medicine have been discussed based on the current literature and the perspectives have been drawn. Various coating strategies such as coating with hydrogel, antibiotic, or other antimicrobial agents have been reviewed.

Bilateral Ureteral Stenosis with Hydronephrosis as First Manifestation of Granulomatosis with Polyangiitis (Wegener's Granulomatosis): A Case Report and Review of the Literature

Ureteral stenosis is a rare manifestation of granulomatosis with polyangiitis (formerly known as Wegener's granulomatosis). We report the case of a 76-year-old woman with progressive renal failure in which bilateral hydronephrosis due to ureteral stenosis was the first manifestation of the disease. Our patient also had renal involvement with pauci-immune crescentic glomerulonephritis associated with high titers of anti-proteinase 3 c-ANCAs, but no involvement of the upper or lower respiratory tract. The hydronephrosis and renal function rapidly improved under immunosuppressive therapy with high-dose corticosteroids and intravenous pulse cyclophosphamide. We reviewed the literature and found only ten other reported cases of granulomatosis with polyangiitis/Wegener's granulomatosis and intrinsic ureteral stenosis: in two cases, the presenting clinical manifestation was unilateral hydronephrosis and in only two others was the hydronephrosis bilateral, but this complication developed during a relapse of the disease. This case emphasizes the importance of including ANCA-related vasculitis in the differential diagnosis of unusual cases of unilateral or bilateral ureteral stenosis.

Cushing syndrome with acute kidney injury due to ureteral stones in a 6-year-old boy

Cushing syndrome (CS) is rare in children. The clinical presentation of CS varies according to extent and duration of glucocorticoid excess, and urolithiasis is a common complication. We report the first case of a patient with CS associated with acute kidney injury (AKI) due to urolithiasis. A 6-year-old boy presented to the Emergency Department with seizure. On physical examination, he had clinical features of CS and high blood pressure. Brain computed tomography (CT) suggested posterior reversible encephalopathy syndrome due to hypertension. On evaluation of hypertension, laboratory tests suggested adrenocortical tumor, but abdominal CT suggested pheochromocytoma. During further evaluation, his condition deteriorated with AKI due to bilateral ureteral stones, for which the patient underwent continuous renal replacement therapy in the intensive care unit. After controlling hypercortisolism with etomidate and performing ureteral stent indwelling, an adrenal mass was resected and histologically confirmed as an adrenocortical adenoma. We review the clinical manifestations, diagnosis, and management of CS associated with urolithiasis and AKI. Early recognition and careful monitoring of urolithiasis in CS patients are important to avoid severe complications of urolithiasis.

Predictive biomarkers of IgA vasculitis with nephritis by metabolomic analysis

BACKGROUND

IgA vasculitis (IgAV) is the most common vasculitis of childhood. Renal involvement defines late morbidity of the disease. A better understanding of the pathophysiology of the progression to kidney disease and predictive biomarkers are required for better management of IgAV and its nephritis (IgAVN).

OBJECTIVES

An untargeted metabolomics approach was performed to reveal the underlying molecular mechanism of disease pathogenesis and to define potential biomarkers from plasma samples from IgAV and IgAVN patients.

METHODS

Forty-five active IgAV patients (H) and six healthy controls (C) were enrolled in the study. Plasma samples were collected on the same day of diagnosis and before any immunosuppressive treatment was initiated. At the time of diagnosis and sample collection, none of the patients had renal involvement. We used Quadrupole Time of Flight Mass Spectrometry (Q-TOF LC/MS) to investigate the alterations in plasma metabolomic profiles. Three separate pools were created: healthy controls (group C), active IgAV patients who did not develop renal involvement (group H), and patients who developed IgAVN at follow up (group N). Peak picking, grouping, and comparison parts were performed via XCMS (https://xcmsonline.scripps.edu/) software.

RESULTS

At follow-up, IgAVN developed in 6 out of 45 IgAV patients. The median time of renal involvement development is 23 days (range 5-45 days). Of these, 3 had nephritic proteinuria, one had nephrotic proteinuria, and 2 had microscopic hematuria. There were no significant differences in gender, age, clinical manifestations, and laboratory findings between the six patients who developed renal involvement and those who did not. In multivariate analysis, there was no significant association between any of the defined demographic and clinical characteristics (male sex, gastrointestinal system involvement, joint involvement, CRP, WBC, PLT) and the occurrence of renal involvement. Totally 2618 peaks were detected for group H, N, and C. Among them, 355 peaks were found to be statistically significant and reliable (p<0.05), and 155 of these peaks were found to be changed (fold change >1.5) between the groups C and H, and 66 peaks were found to be changed (fold change >1.5) between the groups H and N. The number of the peaks on the intersection of the peaks found to be different between the groups (C and H) and (H and N) was 39. Based on putative identification results, 15 putatively identified metabolites matched with 11 peaks were presented as biomarker candidates after careful evaluation with a clinical perspective.

CONCLUSION

We suggest that DHAP (18:0), prostaglandin D2/I2, porphobilinogen, 5-methyltetrahydrofolic acid, and N-Acetyl-4-O-acetylneuraminic acid/N-Acetyl-7-O-acetylneuraminic acid may serve as biomarkers for predicting kidney disease. Future studies with larger groups of IgAV patients are needed to validate the identified metabolic profile.

Macrophage-secreted TGF-β1 contributes to fibroblast activation and ureteral stricture after ablation injury

Iatrogenic injury to the healthy ureter during ureteroscope-guided ablation of malignant or nonmalignant disease can result in ureteral stricture. Transforming growth factor (TGF)-β1-mediated scar formation is considered to underlie ureteral stricture, but the cellular sources of this cytokine and the sequelae preceding iatrogenic stricture formation are unknown. Using a swine model of ureteral injury with irreversible electroporation (IRE), we evaluated the cellular sources of TGF-β1 and scar formation at the site of injury and examined in vitro whether the effects of TGF-β1 could be attenuated by pirfenidone. We observed that proliferation and α-smooth muscle actin expression by fibroblasts were restricted to injured tissue and coincided with proliferation of macrophages. Collagen deposition and scarring of the ureter were associated with increased TGF-β1 expression in both fibroblasts and macrophages. Using in vitro experiments, we demonstrated that macrophages stimulated by cells that were killed with IRE, but not LPS, secreted TGF-β1, consistent with a wound healing phenotype. Furthermore, using 3T3 fibroblasts, we demonstrated that stimulation with paracrine TGF-β1 is necessary and sufficient to promote differentiation of fibroblasts and increase collagen secretion. In vitro, we also showed that treatment with pirfenidone, which modulates TGF-β1 activity, limits proliferation and TGF-β1 secretion in macrophages and scar formation-related activity by fibroblasts. In conclusion, we identified wound healing-related macrophages to be an important source of TGF-β1 in the injured ureter, which may be a paracrine source of TGF-β1 driving scar formation by fibroblasts, resulting in stricture formation.

Positive outcomes of phosphodiesterase type 5 inhibitor on histopathologic and biochemical changes induced by ureteral obstruction

OBJECTIVES

We examined the effects of tadalafil, one of the phosphodiesterase type 5 (PDE5) inhibitors, in a rat model of with partial and complete unilateral ureteral obstruction (UUO).

METHODS

The rats were divided into 5 groups: sham (n=6), partial unilateral ureteral obstruction (PUUO, n=6), PUUO with tadalafil treatment (PUUO+T; Cialis, 10 mg/72 h, intragastric; Lilly, Indianapolis, Indiana, USA), complete unilateral ureteral obstruction (CUUO, n=6), and CUUO with tadalafil treatment (CUUO+T).

RESULTS

Fifteen days after the UUO, the ureter presented changes in the layers of urothelium and significant infiltration of inflammatory cells in the PUUO and CUUO groups. Compared with the sham, PUUO and CUUO groups had severe increased inflammatory cell infiltration. The urothelial epithelium exhibited cell degeneration and loss because of the swollen, atrophic, and denuded epithelial cells in the PUUO and CUUO groups. In the PUUO+T and CUUO+T groups, the urothelium revealed less epithelial cell degeneration and loss.The expressions of α-smooth muscle actin (α-SMA) and transforming growth factor-β (TGF-β) exhibited up-regulation in the PUUO and CUUO groups. The expression of TGF-β decreased positively correlated with that of α-SMA in the tadalafil therapy groups, PUUO+T and CUUO+T.

CONCLUSION

The phosphodiesterase type 5 inhibitor's tadalafil reduced expressions of α-SMA and TGF-β in the obstructed ureters, measured by biochemical examinations. In addition, tadalafil decreased urothelium degeneration due to the decreased epithelial cell loss and inflammatory cell infiltration. Our results show that tadalafil prevents or slows down the onset of ureter inflammation and urothelial degeneration in rats with UUO.

Bilateral Giant Hydronephrosis with Normal Serum Creatinine Level in an Elderly Female

Giant hydronephrosis is rare and usually presents during childhood as a unilateral renal mass due to congenital anomalies such as pelvi-ureteral junction obstruction. In adulthood, however, other etiologies such as urolithiasis may supervene. We report on a 75-year-old female patient who presented with right-sided abdominal pain. She had a visible right renal mass with smooth surface and cystic consistency. Urine analysis showed 60–80 pus cells/HPF and serum creatinine level was 1.2 mg/dL. Imaging revealed hugely dilated kidneys with right severe hydronephrosis and lost renal parenchyma due to a large middle ureteral stone. The left kidney had variable parenchymal thickness which was better at the lower pole with multiple stones. After counselling of the patient, simultaneous left pyelolithotomy with placement of a left JJ stent and right nephrostomy tube were done. Then, renal isotope scanning revealed diminished total glomerular filtration rate (54.6 mL/min/1.73 m²) with better left split function (61.2 vs. 38.8%). Accordingly, a right ureterolithotomy was done and the patient was followed up for 1 year with variable serum creatinine level between 1.2 and 1.5 mg/dL.

Idiosyncratic reaction after injection of polyacrylate - polyalcohol copolymer

Context:

Polyacrylate-polyalcohol copolymer is a synthetic product, non-biodegradable, with low rate of therapeutic failure and lower incidence of reactions at the site of injection, when compared to biodegradable agents. We report an unprecedent, exuberant and persistent inflammatory reaction following injection of that substance.

Patient:

a 17 years-old patient with vesico-ureteral reflux and complete pyelocaliceal right duplication was submitted to treatment with polyacrylate-polyalcohol copolymer (STING technique). In the seventh day of post-operatory, she presented intense dysuria and hypogastric pain, without laboratory exams alterations; a symptomatic treatment was started. After two months, the symptoms persisted and an ultrasound detected thickening of bladder wall close to the uretero-vesical junction. After that exam, a cystostopic biopsy showed epithelial hyperplasia with increased edema of lamina propria, suggesting an adverse reaction to the polymer. After four months, there was complete remission, but the reflux persisted with the same grade.

Hypothesis:

This is an unprecedent reaction following injection of this copolymer. The presence of characteristics such as absence of infection, temporal relation between treatment and beginning of symptoms, and detection of epithelial hyperplasia at the local of injection reinforce the hypothesis of association of the substance and adverse reaction. In that patient, important complains motivated early investigation of urinary tract, that confirmed those aspects. Maybe if that reaction had occurred in patients with lower capacity of expression (such as in infants) it would be unnoticed.

Bilateral hydronephrosis due to obstructive ureteral stone associated with norovirus gastroenteritis

Recently, cases of urinary tract calculi causing hydronephrosis and postrenal renal failure associated with viral gastroenteritis were documented, yet few were related to norovirus. During norovirus gastroenteritis, observation of oliguria, aciduria, low FENa value, and elevation of blood or urinary uric acid level may necessitate clinical workout for nephrolithiasis.

Pediatric urolithiasis associated with acute gastroenteritis: an inpatient database study in Japan

Pediatric urolithiasis associated with acute gastroenteritis (AGE) has not been systematically investigated, including its prevalence, risk estimate, and outcome. Using a national inpatient database in Japan, we searched for children (≤59 months old) who were hospitalized for AGE and those complicated by urolithiasis over a 24-month period. We found 23 cases of urolithiasis among 62,800 children who were hospitalized for AGE (3.7 cases/10,000 AGE admissions). AGE was associated with an increased risk of urolithiasis (odds ratio 2.01; p = 0.015). The patients' mean age was 24 months and there was male dominance. Four patients had chronic medical conditions, including two with renal conditions. None of the patients had congenital metabolic disorders. Nine patients had causative agents for AGE, including rotavirus (n = 5), norovirus (n = 2), and bacteria (n = 2). Two patients required placement of a nephrostomy tube and the remaining 21 patients were discharged without invasive procedures.

CONCLUSION

Childhood AGE is associated with a twofold risk of urolithiasis in a hospitalized cohort, but the absolute risk is low. Our study shows that AGE-related urolithiasis occurs through a variety of pathogens, and the outcomes of patients are favorable, which is in contrast to previous reports. What is Known: • There are several sporadic reports of pediatric urolithiasis associated with acute gastroenteritis (AGE), predominantly from Japan. • The epidemiology of AGE-related urolithiasis is however unclear. What is New: • AGE is associated with a two-fold risk of urolithiasis in a hospitalized cohort, with its absolute risk of 3.7 cases/10,000 AGE admissions.

Renal Expression and Urinary Excretion of Na-K-2Cl Cotransporter in Obstructive Nephropathy

Renal damage due to urinary tract obstruction accounts for up to 30% of acute kidney injury in paediatrics and adults. Bilateral ureteral obstruction (BUO) is associated with polyuria and reduced urinary concentrating capacity. We investigated the renal handling of water and electrolytes together with the renal expression and the urinary excretion of the Na-K-Cl cotransporter (NKCC2) after 1 (BUO-1), 2 (BUO-2), and 7 (BUO-7) days of release of BUO. Immunoblotting and immunohistochemical studies showed that NKCC2 expression was upregulated in apical membranes both from BUO-2 and from BUO-7 rats. The apical membrane expression, where NKCC2 is functional, may be sufficient to normalize water, potassium, sodium, and osmolytes tubular handling. NKCC2 abundance in homogenates and mRNA levels of NKCC2 was significantly decreased in almost all groups suggesting a decrease in the synthesis of the transporter. Urinary excretion of NKCC2 was increased in BUO-7 groups. These data suggest that the upregulation in the expression of NKCC2 in apical membranes during the postobstructive phase of BUO could contribute to improving the excretion of sodium and consequently also the excretion of potassium, osmolytes, and water. Moreover, the increase in urinary excretion of NKCC2 in BUO-7 group could be a potential additional biomarker of renal function recovery.

The profile of patients with obstructive uropathy in Cameroon: case of the Douala General Hospital

Introduction

Obstructive uropathy can lead to irreversible kidney damage. The etiology largely determined by the patient's age can be benign or malignant. This study aimed at determining the profile and outcome of patients with obstructive uropathy in Cameroon.

Methods

A cross sectional study carried out in the urology unit of the Douala General Hospital, including patients with a diagnosis of obstructive uropathy seen from January 2004 to December 2013. Clinical profile, treatment and outcome data were obtained from patients records.

Results

Of the 229 patients included 69% were men, mean age 50 ±18 years. Associated comorbidities were hypertension, diabetes, and HIV. Mean haemoglobin 8,40±2,4g/dl, mean GFR 10,3 ±10ml/min, 94 (41%) patients needed emergency dialysis. Symptoms at presentation: asthenia (57%), anorexia (55%), loin pain (37%), vomiting (28%), oedema (20%), and anuria (15%). Urinary tract infection was present in 33 patients. Main aetiologies of obstruction: urolithiasis (35%), begnin prostatic hypertrophy (27%), prostatic cancer (12%), cervical cancer (16%), and congenital malformations (5%). Drainage was effective in 102 (45%) patients, 63 (28%) recovered completely, 91 (41%) were loss to follow up, 49 (22%) died and more women (p = 0.02). Mortality was associated with prostatic cancer (p = 0.000), cervical cancer (p = 0.004) and radiotherapy (p = 0.03).

Conclusion

Patients with obstructive uropathy presented with significant impaired renal function. Main causes were urinary stones, prostatic hypertrophy, prostatic and cervical cancers. Renal recovery was poor, loss to follow up and mortality high. Specific strategies to target improvement in renal recovery and patient's survival are needed in this patient's group.

Bilateral Ureteral Obstruction in Children after Appendectomy

Acute renal failure due to bilateral ureteral obstruction is a rare complication after appendectomy in children. We report a case of bilateral ureteric obstruction in a 14-year-old boy nine days after surgery for an acute appendicitis. After saline-filling of the urinary bladder, transabdominal ultrasound demonstrated bilateral hydronephrosis of moderate degree. No abscess was found with CT but presence of millimetric stones on both distal ureters was shown, with bilateral calyceal dilatation. Cystoscopy revealed inflammatory changes in the bladder base. Following introduction of bilateral ureteric stents, there was rapid normalisation of urinary output and serum creatinine.

Inhibition of Mitochondrial Complex-1 Prevents the Downregulation of NKCC2 and ENaCα in Obstructive Kidney Disease

Ureteral obstruction with subsequent hydronephrosis is a common clinical complication. Downregulation of renal sodium transporters in obstructed kidneys could contribute to impaired urinary concentrating capability and salt waste following the release of a ureteral obstruction. The current study was undertaken to investigate the role of mitochondrial complex-1 inhibition in modulating sodium transporters in obstructive kidney disease. Following unilateral ureteral obstruction (UUO) for 7 days, a global reduction of sodium transporters, including NHE3, α-Na-K-ATPase, NCC, NKCC2, p-NKCC2, ENaCα, and ENaCγ, was observed, as determined via qRT-PCR and/or Western blotting. Interestingly, inhibition of mitochondrial complex-1 by rotenone markedly reversed the downregulation of NKCC2, p-NKCC2, and ENaCα. In contrast, other sodium transporters were not affected by rotenone. To study the potential mechanisms involved in mediating the effects of rotenone on sodium transporters, we examined a number of known sodium modulators, including PGE2, ET1, Ang II, natriuretic peptides (ANP, BNP, and CNP), and nitric oxide synthases (iNOS, nNOS, and eNOS). Importantly, among these modulators, only BNP and iNOS were significantly reduced by rotenone treatment. Collectively, these findings demonstrated a substantial role of mitochondrial dysfunction in mediating the downregulation of NKCC2 and ENaCα in obstructive kidney disease, possibly via iNOS-derived nitric oxide and BNP.