Acute Renal Colic Due to Immunoglobulin Free Light Chain Kidney Stones: A Case Report of an Unusual Complication of Multiple Myeloma.

Kidney failure is common in patients with a monoclonal gammopathy, most frequently due to hypercalcemia or myeloma cast nephropathy. Immunoglobulin crystallization is an uncommon phenomenon that also results in kidney injury. We report the case of a 74-year-old man with recurrent renal colic and acute kidney injury. He presented with κ light chain Bence-Jones proteinuria, hypogammaglobulinemia, anemia, and high plasma κ light chain level, leading to the diagnosis of κ light chain multiple myeloma. One calculus was collected and its analysis revealed a unique protein structure consisting of κ immunoglobulin free light chain. Genetic sequencing of the κ light chain identified a subgroup of variable domain previously identified as prone to crystallization. Eight cycles of cyclophosphamide-bortezomib-dexamethasone chemotherapy resulted in a partial hematologic response and kidney recovery without recurrence of renal colic. This rare case of urinary light chain nephrolithiasis highlights the importance of genetic and molecular analysis of the immunoglobulin variable domain to better understand the wide spectrum of monoclonal gammopathies.

Opening an onconephrology clinic: recommendations and basic requirements.

Onconephrology is a rapidly evolving subspeciality that covers all areas of renal involvement in cancer patients. The complexity of the field may benefit from well-defined multidisciplinary management administered by a dedicated team. Since there is an increasing need to address the needs of this population in dedicated outpatient clinics, it is critical to highlight basic characteristics and to suggest areas of development. In this brief perspective article, we analyse the requirements of an onconephrology clinic in terms of logistics, critical mass of patients and building a multidisciplinary team. We will further discuss which patients to refer and which conditions to treat. The last part of the article is dedicated to education and performance indicators and to analysis of the potential advantages of applying the hub-and-spoke model to this field. The ultimate aim of this experience-based article is to initiate debate about what an onconephrology outpatient clinic might look like in order to ensure the highest quality of care for this growing population of patients.

In Hemodialysis Patients, Intradialytic Resistance Exercise Improves Osteoblast Function: A Pilot Study.

OBJECTIVE: Abnormalities in mineral and bone metabolism are frequent in chronic kidney disease patients. Physical exercise can improve many indicators of physical functioning, and recent studies showed beneficial effects on bone mineral density in the general population. The aim of this study was to evaluate the effects of resistance exercise training on bone markers and body composition in hemodialysis (HD) patients. DESIGN: This was a randomized controlled trial. SUBJECTS: The study included 13 HD patients (46.2% men). INTERVENTION: Patients were divided into a control group and an exercise group, which performed 8 weeks of intradialytic resistance exercise. Serum sclerostin, bone alkaline phosphatase (BAP), insulin, leptin, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and body composition were measured before and after the exercise period. RESULTS: In the exercise group, BAP levels increased from 11.4 ± 6.5 to 14.6 ± 6.4 U/L (P < .05) and serum 1,25-dihydroxyvitamin D levels from 46.0 ± 23.5 to 87.2 ± 31.8 ng/mL (P < .05). After exercise, serum BAP levels were inversely correlated with serum sclerostin (r = -0.96, P < .05). There was no change in body composition in either group. CONCLUSION: Resistance exercise training appears to be an interesting approach for stimulating BAP production in HD patients and may prevent bone loss and stimulate bone formation.

[Renal toxicity of antineoplasic agents]. / Toxicité rénale des anticancéreux.

"Renal toxicity of antineoplasic agents Renal toxicity of antineoplasic agents is a common complication faced by oncologists and nephrologists whose incidence depends on therapeutic classes used and patient's comorbidities. Nephrotoxicity is variable, according to mecanisms, chronology and potential reversibility. Besides acute kidney injury and/or chronic kidney disease, clinical features include several urinary abnormalities (mainly proteinuria). The onset of renal toxicity may directly compromise vital prognosis and may lead to the interruption of medications affecting cancer-specific mortality. Nephrotoxicity prevention (when feasible) and rapid diagnosis are essential to optimize cancer-patient medical care."

Toxicité rénale des anticancéreux La toxicité rénale des anticancéreux est une complication à laquelle les oncologues et les néphrologues sont fréquemment confrontés, dont l'incidence est liée aux classes de molécules utilisées et aux comorbidités des patients. Cette toxicité est variable dans ses mécanismes, sa chronologie et son éventuelle réversibilité. Les atteintes cliniques incluent, outre l'insuffisance rénale aiguë et/ou chronique, divers troubles hydroélectrolytiques ainsi que des anomalies urinaires (en premier lieu une protéinurie). La survenue d'une toxicité rénale peut directement compromettre le pronostic vital mais également conduire à l'interruption d'anticancéreux améliorant la survie oncologique. La prévention (quand elle est possible) et l'identification rapide de toute toxicité rénale sont donc indispensables afin d'optimiser la prise en charge du patient cancéreux.

A new expression of immune checkpoint inhibitors' renal toxicity: when distal tubular acidosis precedes creatinine elevation.

The main manifestation of acute interstitial nephritis (AIN) due to immune checkpoint inhibitors is acute kidney injury. We report here a biopsy-proven AIN revealed by tubular acidosis. This case highlights that immune checkpoint inhibitor prescribers must be aware of electrolytic disorders since tubular dysfunction can precede serum creatinine increase and reveal renal toxicity.

Severe tubulointerstitial nephritis: tracking tuberculosis even in the absence of renal granuloma.

Extra-pulmonary tuberculosis is frequently located in the kidneys and, in such cases, could be associated with a granulomatous interstitial nephritis. Granulomas are not always detected, especially in human immunodeficiency virus (HIV)-positive patients. We report here a case of tubulointerstitial nephritis without granulomas in an HIV-negative patient. Since all laboratory tests failed to isolate Mycobacterium tuberculosis in the kidney, a targeted biopsy guided by positron emission tomography-computed tomography was performed on a mediastinal node, revealing a positive culture. After 6 months of treatment, no recovery of the renal injury has been observed.

Adjunction of a MEK inhibitor to Vemurafenib in the treatment of metastatic melanoma results in a 60% reduction of acute kidney injury.

INTRODUCTION: A combined therapy MEK inhibitor, Cobimetinib (CB) and BRAF inhibitor, Vemurafenib (VMF), results in an improvement in progression-free survival among patients with BRAF V600-mutated metastatic melanoma. VMF skin adverse effects attributed to ERK paradoxical activation are decreased by the adjunction of CB. The aim of this study was to determine if this combination also improved the renal side effects of VMF. PATIENTS AND METHODS: To investigate the incidence of acute kidney injury (AKI), we conducted a retrospective observational monocentric study in Lyon Sud University Hospital in France. We included 38 patients with metastatic BRAF-mutated melanomas treated by VMF and CB between March 2015 and June 2016. According to the NCI-CTCAE classification, AKI was defined as an increase in serum creatinine exceeding the baseline concentration by 1.5-fold. Serum creatinine was measured before treatment, then on a monthly basis during treatment, and 1 month after treatment discontinuation. Patients were divided into two main groups: AKI-positive (AKI+) and AKI-negative (AKI-), and further subdivided into three groups according to AKI severity (stage 1-5). RESULTS: Of 38 patients, 29 (76%) were AKI-, and all 9 AKI+ patients (24%) were diagnosed within the first trimester of treatment. Three-quarters of AKI (n = 7, 77%) had stage 1 AKI and the remaining 23% stage 2 AKI. Pre-treatment renal function was significantly better in AKI+ group: 105 vs. 80 ml/min/1.73m² AKI-, p = 0.009. Compared to previous results, the AKI incidence under the combined VMF-CB vs. VMF monotherapy was reduced by 60%. CONCLUSION: We reported a reduced incidence and severity of nephrotoxicity of the association inhibitors of BRAF and MEK compared to a BRAF inhibitor monotherapy.

New insights into renal toxicity of the B-RAF inhibitor, vemurafenib, in patients with metastatic melanoma.

PURPOSE: Vemurafenib (VMF) is a B-RAF inhibitor used in the treatment of B-RAF-V600-mutant metastatic melanomas. Reports of acute kidney injury (AKI) in patients treated with VMF are scarce. METHODS: To investigate the incidence and severity of AKI, we conducted a retrospective, observational, monocentric study in the Lyon Sud Hospital University, France, which included 74 patients with metastatic B-RAF-mutated melanomas treated with VMF, between June 2011 and August 2014. According to the Kidney Disease Improving Global Outcomes Guidelines, AKI is defined as an increase in serum creatinine concentration exceeding the baseline concentration by 1.5 fold. Serum creatinine was thus determined before treatment, on a monthly basis during treatment, and 3 months after treatment discontinuation. Patients were divided into two main groups: AKI-positive (AKI+) and AKI-negative (AKI-) and further subdivided into three groups according to AKI severity (stage 1, 2 or 3). To visualize the tissue damage caused by VMF, kidney biopsies were performed for two stage 1 AKI+ patients. RESULTS: Of the 74 patients, 30 (40.5 %) were AKI-, and of the 44 AKI+ patients (59.5 %), 29 (66 %) were diagnosed within the first three months of treatment. There were significantly more men in the AKI+ group: n = 33 (75 %) versus n = 12 (40 %) women, p = 0.004 with an odds ratio for developing AKI of 4.6 (95 % CI 1.48-14.23). Most AKI + cases were considered as stage 1 (n = 40; 91 %) and the remaining four (9 %) as stage 2 AKI. Kidney biopsies revealed interstitial fibrosis and acute focal tubular damage. However, renal failure was reversible in 80 % of patients within 3 months of VMF discontinuation. CONCLUSIONS: We observed frequent, reversible, moderately severe AKI with some histological evidence of tubular and interstitial damage in VMF-treated patients, suggesting that renal function should be carefully monitored in male patients, especially during the first 3 months.