2022 Recommendations of the AFU Lithiasis Committee: Epidemiology, stone analysis and composition.

The incidence of urinary lithiasis is rising steadily in industrialized countries, and its prevalence in the general population of France is estimated at 10%. Renal colic accounts for 1-2% of emergency department consultations. At a time when the new LASER stone fragmentation techniques available to urologists will lead to ever finer in situ pulverization of stones, the exact identification of the compounds that form the stone is essential for etiological diagnosis. Constitutional analysis by infrared spectrophotometry or X-ray diffraction is therefore recommended, to be complemented by morphological typing of the calculi. METHODOLOGY: These recommendations have been drawn up using two methods: the Recommendation for Clinical Practice (RPC) method and the ADAPTE method, depending on whether or not the issue was considered in the EAU recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU 2022] and their adaptability to the French context.

2022 Recommendations of the AFU Lithiasis Committee: Medical management - from diagnosis to treatment.

The morphological-compositional analysis of urinary stones allows distinguishing schematically several situations: dietary, digestive, metabolic/hormonal, infectious and genetic problems. Blood and urine testing are recommended in the first instance to identify risk factors of urinary stone disease in order to avoid recurrence or progression. The other objective is to detect a potential underlying pathology associated with high risk of urinary stone disease (e.g. primary hyperparathyroidism, primary or enteric hyperoxaluria, cystinuria, distal renal tubular acidosis) that may require specific management. Lifestyle-diet measures are the basis of the management of all stone types, but pharmacological treatments may be required. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendation (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU 2022] and their adaptability to the French context.

Trajectory of extracellular fluid volume over time and subsequent risks of end-stage kidney disease and mortality in chronic kidney disease: a prospective cohort study.

BACKGROUND: Extracellular fluid volume (ECF) is independently associated with chronic kidney disease (CKD) progression and mortality in patients with CKD, but the prognostic value of the trajectory of ECF over time beyond that of baseline value is unknown. OBJECTIVES: To characterize ECF trajectory and evaluate its association with the risks of end-stage kidney disease (ESKD) and mortality. METHODS: From the prospective tricentric NephroTest cohort, we included 1588 patients with baseline measured glomerular filtration rate (mGFR) ≥15 mL min-1 /1.73 m2 and ECF measurement. ECF and GFR were measured repeatedly using the distribution volume and clearance of 51 Cr-EDTA, respectively. ESKD and mortality were traced through record linkage with the national registries. Adjusted shared random-effect joint models were used to analyse the association between the trajectory of ECF over time and the two competing outcomes. RESULTS: Patients were mean age 58.7 years, 66.7% men, mean mGFR of 43.6 ± 18.6 mL min-1 /1.73 m2 and mean ECF of 16.1 ± 3.6 L. Over a median follow-up of 5.3 [IQR: 3.0;7.4] years, ECF increased by 136 [95%CI 106;167] mL per year on average, whilst diuretic prescription and 24-hour urinary sodium excretion remained stable. ESKD occurred in 324 (20.4%) patients, and 185 (11.6%) patients died before ESKD. A higher current value of ECF was associated with increased hazards of ESKD (adjusted hazard ratio [aHR]: 1.12 [95%CI 1.06;1.18]; P < 0.001 per 1 L increase in ECF), and death before ESKD (aHR: 1.10 [95%CI 1.04;1.17]; P = 0.002). CONCLUSIONS: The current value of ECF was associated with the risks of ESKD and mortality, independent of multiple potential confounders, including kidney function decline. This highlights the need for a close monitoring and adjustment of treatment to avoid fluid overload in CKD patients.

Conservative three-quarter versus subtotal seven-eighths parathyroidectomy in secondary hyperparathyroidism.

OBJECTIVE: There is at present no consensus concerning surgical techniques for secondary hyperparathyroidism (SHPT) in end-stage renal disease (ESRD). Although both subtotal and total parathyroidectomy provide low rates of recurrence, they may induce hypoparathyroidism, damaging the bone and cardiovascular systems. The aim of our study was to compare 3/4 and 7/8 parathyroidectomy in this population and to discuss the potential benefit of more conservative treatment. STUDY DESIGN: Prospective observational study in a university teaching hospital between 2010 and 2014. METHODS: The study included 34 consecutive ESRD patients with SHPT: 19 underwent 3/4 parathyroidectomy (group A*3/4) and 15 underwent 7/8 parathyroidectomy (group B*7/8). Serum intact 1-84 PTH levels (before and 6 months after surgery) and hospital stay were compared between the two groups. RESULTS: Before surgery, PTH levels were similar between the two groups. At month 6 following surgery, median PTH levels were significantly higher in group A*3/4 than in group B*7/8 (109 versus 24pg/mL, respectively; P<0.0006). Hospital stay was shorter in group A*3/4 (4.79 versus 6.80 days, respectively; P=0.008). Postoperative hypoparathyroidism requiring long-term calcium and 1alpha(OH) D3 treatment was reported in 5% of patients in group A*3/4 and 26% of patients in group B*7/8 (P=0.04). CONCLUSIONS: In this preliminary study, 3/4 conservative parathyroidectomy seemed effective and safe, with less reported morbidity than 7/8 parathyroidectomy, as assessed by lower rates of irreversible hypoparathyroidism and shorter hospital stay. LEVEL OF EVIDENCE: 3b, individual case-control study.

[The role of physicochemistry in urology and nephrology, selected results obtained during the last ten years]. / La place de la physicochimie en urologie et en néphrologie : le bilan de 10ans de collaboration entre physiciens, chimistes et praticiens hospitaliers.

INTRODUCTION: The presence of pathological calcifications, which can be either concretions or ectopic call for physicochemical characterisation techniques in order to define a significant diagnosis. The aim of this review is to present a set of characterisation techniques able to describe at the micrometer scale their structural and chemical characteristics and show their place at the hospital. METHOD: Results already published in the last ten years based on characterisation techniques present in laboratories or specific to large-scale instruments are presented. Their usefulness for the clinician is discussed. RESULTS: The presence and role of heavy metals in urinary stones through data collected through µX-ray fluorescence is debated. If these data suggest a simple substitution process of calcium, recent data suggest that weddellite is associated to a Zn-rich environment, partly favoured by an inflammation process. Investigation on the chemistry and the structure of unusual deposits in kidney biopsies show a great chemical diversity of ectopic calcifications. Such diversity shows that staining procedures to characterize such deposits are obsolete. Finally, several diseases which can be assessed through techniques specific to large-scale instruments and defined by the clinician are presented. CONCLUSION: The chemical and structural complexity of pathological calcifications call for a characterization through physicochemical techniques. Only such approach allows the clinician to define a significant diagnosis and to care the patient.

Calcium oxalate precipitation by diffusion using laminar microfluidics: toward a biomimetic model of pathological microcalcifications.

The effect of mixing calcium and oxalate precursors by diffusion at miscible liquid interfaces on calcium oxalate crystalline phases, and in physiological conditions (concentrations and flow rates), is studied using a microfluidic channel. This channel has similar dimensions as the collection duct in human kidneys and serves as a biomimetic model in order to understand the formation of pathological microcalcifications.

[First-line screening guidelines for renal stone disease patients: a CLAFU update]. / Bilan métabolique et prise en charge médicale de la lithiase: une mise au point du CLAFU.

This text summarizes the CLAFU first-line screening guidelines for renal stone disease patients. We have focused on the useful information provided by renal stone analysis and also the identification of relevant stone risk factors detected in a 24-hour urine collection. Indeed, evaluation of water, sodium and protein intake may be easily achieved in a current clinical setting and allows a useful pedagogic tool for patients' advices and follow-up: daily diuresis above 2000 mL, calcium intake between 800 mg and 1 g/day, a moderate daily sodium and proteins restricted diet (<9 g and <1.2 g/kg per day respectively). General therapeutical principles are reviewed, including circumstances requiring specialized management.

Intrarenal urothelium proliferation: an unexpected early event following ischemic injury.

Identification of renal cell progenitors and recognition of the events contributing to cell regeneration following ischemia-reperfusion injury (IRI) are a major challenge. In a mouse model of unilateral renal IRI, we demonstrated that the first cells to proliferate within injured kidneys were urothelial cells expressing the progenitor cell marker cytokeratin 14. A systematic cutting of the injured kidney revealed that these urothelial cells were located in the deep cortex at the corticomedullary junction in the vicinity of lobar vessels. Contrary to multilayered bladder urothelium, these intrarenal urothelial cells located in the upper part of the medulla constitute a monolayered barrier and express among uroplakins only uroplakin III. However, like bladder progenitors, intrarenal urothelial cells proliferated through a FGF receptor-2 (FGFR2)-mediated process. They strongly expressed FGFR2 and proliferated in vivo after recombinant FGF7 administration to control mice. In addition, IRI led to FGFR phosphorylation together with the selective upregulation of FGF7 and FGF2. Conversely, by day 2 following IRI, renal urothelial cell proliferation was significantly inhibited by FGFR2 antisense oligonucleotide administration into an intrarenal urinary space. Of notice, no significant migration of these early dividing urothelial cells was detected in the cortex within 7 days following IRI. Thus our data show that following IRI, proliferation of urothelial cells is mediated by the FGFR2 pathway and precedes tubular cell proliferation, indicating a particular sensitivity of this structure to changes caused by the ischemic process.

Acute oxalate nephropathy: A new etiology for acute renal failure following nonrenal solid organ transplantation.

Acute renal insufficiency (ARI) is a frequent complication of nonrenal solid organ transplantation and may be responsible for an unfavorable outcome, particularly if dialysis is required. The etiology of post-transplantation ARI is poorly understood, with only isolated clinical cases being reported, most imputed to drug toxicity. We report here, the first three observations of irreversible ARI associated with acute oxalate nephropathy (AON) in the course of nonrenal organ transplants: a lung transplant and a lung-liver transplant in two patients with mucoviscidosis, and a cardiac transplant. The diagnosis of AON was made histologically. In all three cases, the ARI supervened after prolonged consumption of antibiotics capable of interfering with the colonic flora, and leading to enteric hyperoxaluria. The recognition of AON as a cause of post-transplantation, ARI underlines hyperoxaluria and digestive hyperabsorption of oxalate as specific risk factors for AON and should permit better posttransplant care of these patients.

[Prophylactic prescription of low-molecular-weight heparin in the non-surgical setting: impact of recommendations]. / Prescription préventive des héparines de bas poids moléculaire en milieu non chirurgical: l'impact de recommandations.

OBJECTIVE: Low-molecular-weight heparins (LMWH) had official approval for use for venous thromboembolism prophylaxis only for surgery patients when this survey was conducted, but were nevertheless often used in non-surgery patients. We conducted this "before and after" survey from May 1998 to April 1999 to assess the impact of the recommendations implemented in the beginning of 1999. METHODS: Data on the use of LMWH were collected on three different days within a three week interval in all non-surgery departments at the Tenon hospital before distribution of expert recommendations early in 1999. Published in La Presse Médicale in January 2000, these recommendations issued from an external panel of 43 experts who were contacted to establish a consensus opinion using the Delphi method. Data were again collected on three different days after implementation of the recommendations. Implementation was based on a patient-specific prescription order form requested by the hospital pharmacy for delivery to the department. RESULTS: Data were collected for 121 prescriptions prior to the recommendations and for 158 after. Sex-ratio, mean age and percentage of LMWH prescriptions did not differ significantly between the two periods. There was a lower number of non-appropriate prescriptions after implementation of the recommendations from 54.5% to 35.4% (p = 0.01) with better conformity for recommendation A (high-risk patients) (36% versus 43%, NS) and for recommendation B (= 2 risk situations or = 1 risk situation and = 2 aggravating factors) (10% versus 22%, p = 0.01). Better conformity of LMWH prescriptions in oncology and radiotherapy departments partially explained this general improvement, but the difference remained significant when excluding these two departments (p = 0.04). CONCLUSION: This study shows that physician compliance with recognized expert recommendations can improve their implementation. This procedure is now in general use in the Tenon hospital.

Acute renal failure in patients over 80 years old: 25-years' experience.

OBJECTIVE: To determine the epidemiological trends, spectrum of etiologies, morbidity and mortality of acute renal failure (ARF) in patients over 80 years old. DESIGN: Historical cohort analysis. SETTING: Intensive care unit (ICU) of nephrology, Tenon Hospital, Paris. PATIENTS AND PARTICIPANTS: The criteria of inclusion was ARF, defined on the basis of a creatinine value over 120 mumol/l, in patients over 80 years of age admitted between October 1971 and September 1996. When moderate chronic nephropathy was pre-existing, ARF was defined by the increase of at least 50% over the basal creatininemia. MEASUREMENTS AND RESULTS: Three hundred and eighty-one patients over 80 years of age were included. The etiology and mechanism of ARF are detailed. 29% of the patients received dialysis. Global mortality at the hospital was 40%. Factors significantly associated with a poor prognosis are identified. Mean survival after hospitalization was 19 months. CONCLUSION: The frequency of admission to ICUs for ARF in patients older than 80 years seems to be on the increase. Mortality is less severe than expected. These patients could benefit from the renal replacement therapy of modern intensive care medicine.

[Intravenous polyclonal immunoglobulins (IVIG): what use in transplantation?]. / Immunoglobulines polyclonales intraveineuses (IVIg): quel intérêt en transplantation?

Intravenous human polyclonal immunoglobulins G (IVIg) were initially used as substitutive therapy for primary and secondary immunodeficiencies then for various autoimmune diseases. More recently they were proposed in organ transplant recipients as they induce a decrease of the anti-HLA antibodies titer in HLA immunized patients. Few retrospective and prospective trials have been performed yet, though they clearly show a beneficial effect of IVIg on kidney graft survival. This paper reviews the different potential mechanisms of action of IVIg their use and potential efficacy in organ transplant recipients.

Bacterial endocarditis associated with crescentic glomerulonephritis in a kidney transplant patient: first case report.

BACKGROUND: Endocarditis-induced crescentic glomerulonephritis is a well-described complication in nontransplant patients. Its occurrence in transplant patients has not been reported to date. METHODS: A 50-year-old man who had received a renal allograft 13 years before and been treated with prednisone, 10 mg/day, was admitted for progressive renal failure, purpura, edema of the lower limbs, and fever. RESULTS: Blood cultures isolated Streptococcus bovis and cardiac ultrasound examination revealed a 23-mm-large vegetation on the mitral valve. His plasma creatinine level was 478 micromol/L and his proteinuria was 5.5 g/day. A renal biopsy showed diffuse crescentic glomerulonephritis. Long-term antibiotic treatment and three methylprednisolone pulses were effective in treating the endocarditis and glomerulonephritis. CONCLUSION: Endocarditis-induced glomerulonephritis is an immune-mediated disease that can also occur on a renal allograft. It is likely that a low daily dose of immunosuppressive treatment may have been a facilitating factor.