[The glomerulus in all its states]

Glomerulonephritis are the result of an inflammatory hit to the glomerulus. They are rare and heterogeneous renal diseases. Each glomerular compartment can be affected. The clinical manifestations present with hematuria, proteinuria and/or impaired renal function, either isolated or combined. Two main clinico-biological syndromes are described: nephrotic syndrome and nephritic syndrome. The latter can present in a more severe form i.e. rapidly progressive glomerulonephritis with the worst prognosis. These different clinical pictures are related to specific glomerular lesions. Thus, podocytic damage is mainly responsible for nephrotic syndromes, mesangial damage is responsible for proteinuria and hematuria and, finally, endothelial damage is responsible for nephritic syndrome and rapidly progressive glomerulonephritis. Therapeutic approaches include non-specific measures, combining both life-style and pharmacological interventions with the aim to reduce risk factors, and specific measures with the use of different immunosuppressive agents.

[Diagnosis and management of renal allograft rejection]

Renal allograft rejection involves many mechanisms of innate and adaptive immunity, responsible for parenchymal inflammatory lesions that negatively impact the long-term outcomes of the renal allograft. The heterogeneous presentations of rejections in terms of clinical, biological and histological aspects make them difficult to manage in daily clinical practice. Indeed, current therapeutic strategies are disappointing in term of long-term outcomes, including graft survival. In this article, we will discuss the main effector mechanisms of rejection and their histological classification, as well as the existing treatments and those currently under evaluation.

[18F]FDG PET/CT imaging disproves renal allograft acute rejection in kidney transplant recipients with acute kidney dysfunction: a validation cohort

PURPOSE

[¹⁸F]FDG PET/CT may predict the absence of acute allograft rejection (AR) in kidney transplant recipients (KTRs) with acute kidney injury (AKI). Still, the proposed threshold of 1.6 of the mean of mean standardized uptake values (mSUVmean) in the renal parenchyma needs validation.

METHODS

We prospectively performed 86 [¹⁸F]FDG PET/CT in 79 adult KTRs who underwent per-cause transplant biopsy for suspected AR. Biopsy-proven polyoma BK nephropathies (n = 7) were excluded. PET/CT was performed 192 ± 18 min after administration of 254.4 ± 30.4 MBq of [¹⁸F]FDG. The SUV_mean was measured in both upper and lower poles of the renal allograft. One-way analysis of variance (ANOVA) and Tukey's studentized range test were sequentially performed. The receiver operating characteristic (ROC) curve was drawn to discriminate "AR" from non-pathological ("normal" + "borderline") conditions.

RESULTS

The median age of the cohort was 55 [43; 63] years, with M/F gender ratio of 47/39. The mean eGFR was 31.9 ± 14.6 ml/min/1.73m². Biopsies were categorized in 4 groups: "normal" (n = 54), "borderline" (n = 9), "AR" (n = 14), or "others" (n = 2). The median [min; max] mSUV_mean reached 1.72 [1.02; 2.07], 1.97 [1.55; 2.11], 2.13 [1.65, 3.12], and 1.84 [1.57; 2.12] in "normal," "borderline," "AR," and "others" groups, respectively. ANOVA demonstrated a significant difference of mSUV_mean among groups (F = 13.25, p < 0.0001). The ROC area under the curve was 0.86. Test sensitivity and specificity corresponding to the threshold value of 1.6 were 100% and 30%, respectively.

CONCLUSION

[¹⁸F]FDG PET/CT may help noninvasively prevent inessential transplant biopsies in KTR with AKI.

[COVID-19 inside dialysis units]

COVID-19 has been the center of global attention and concern for the last months. Patients undergoing dialysis and especially those treated at the hospital are likely to be infected, due to their mandatory presence at the hospital several times a week and due to their intrinsic fragility in regard of chronic kidney disease, often an older age, and the presence of many associated comorbidities. Thereby, patients with chonic kidney disease treated by haemodialysis have higher odds of a more severe COVID-19 infection with a high mortality rate. Prevention is thus a high priority for these patients.

[Kidney injury in COVID-19]

The SARS-CoV-2 virus causes a respiratory distress syndrome, the main symptom of COVID-19 (for "COronaVIrus Disease 2019"). This infectious disease has been causing a major health and socio-economic pandemic since December 2019. The pulmonary alveolus is regarded as the main target of SARS-CoV-2. However, this coronavirus is capable of directly or indirectly affecting other organs, including the kidneys. Here, we summarize the presumed pathophysiology of COVID-19 renal disease. The incidence of acute kidney injury ranges from 0,5 to 22 % of all patients infected with SARS-CoV-2. The need for renal replacement therapy is reported in 5-9 % of patients in intensive care. Histological analysis of renal biopsies mainly shows acute tubular necrosis of varying severity, as well as the congestion of glomerular and peri-tubular capillaries. Endothelitis has been described in few cases. Evidence for a factual inflammation of the glomerulus remains controversial. The medium/long term consequences of COVID-19 nephropathy are unknown and will deserve a tight follow-up.

[Therapeutic innovation in nephrology : 10 years of progress]

Chronic kidney disease (CKD) impairs the quality of life and increases the risk for cardiovascular morbimortality. Intensive research is conducted in order to slow down CKD development and progression. During the past decade, a better understanding of the pathophysiological mechanisms of glomerular diseases has highlighted the benefits of rituximab. Progresses have also been made in the understanding of the mechanisms of autosomal polycystic kidney disease, the most frequent inherited kidney disease. These observations led to the discovery and validation of tolvaptan, a blocker of the V2 receptor of the antidiuretic hormone as an innovative treatment. Type 2 diabetic disease is the leading cause worldwide of endstage kidney disease and dialysis. The development of new drugs, such as the gliflozins (inhibiting the sodium glucose reabsorption in the proximal tubule), has contributed to an improvement in the management of the cardiovascular and renal risks especially reducing congestive heart failure rate. Another important progress in nephrology since the beginning of the new century concerns a more precise estimation of the kidney function, which allows to better evaluate the slope of CKD progression and test the influence of different therapeutic approaches aiming at correcting anemia, hyperkalemia, metabolic acidosis and disturbances of calcium and phosphate. The present review summarizes all of these major advances in the field of CKD diagnosis and treatment, and envisions the future of nephrology for the next decade.

[An unusual cause of kidney disease in a diabetic patient]

Diabetic nephropathy is a complication of diabetes that affects 25-40 % of diabetic patients. This complication is usually associated with other microangiopathic disorders. We describe a case of a patient suffering from type 2 diabetes with proteinuria, and no signs of retinopathy. This case allows us to discuss and review different etiologies of proteinuria in diabetic patients, particularly in patients who don't suffer from retinopathy.

Management of adverse renal events related to alemtuzumab treatment in multiple sclerosis: a Belgian consensus

Alemtuzumab is a humanized monoclonal antibody indicated for the treatment of adult patients with relapsing–remitting multiple sclerosis with active disease. Multiple sclerosis (MS) patients treated with alemtuzumab are at increased risk for autoimmune adverse events (thyroid disorders, immune thrombocytopenia, and renal disease). The use of alemtuzumab has been associated with the development of renal immune-mediated adverse events in 0.3% of patients in clinical trials in MS, which generally occurred within 39 months of the last administration. Both anti-GBM disease and membranous nephropathy have been associated with the use of alemtuzumab. Early detection is necessary to allow for early diagnosis and prevent adverse renal and patient outcomes. Through the implementation of the risk minimization measures, patients can be diagnosed, and treated if needed, early allowing for generally favorable outcomes. This important goal can be reached through health care professional and patient education, careful analysis of the monthly lab tests, and close collaboration between the patient, neurologist, and the nephrologist. This article presents the consensus of Belgian MS specialists and nephrologists on the practicalities of diagnosis, management, and treatment of alemtuzumab-associated renal adverse events based on good clinical practice.

Fluorodeoxyglucose F(18) Positron Emission Tomography Coupled With Computed Tomography in Suspected Acute Renal Allograft Rejection

Management of kidney transplant recipients (KTRs) with suspected acute rejection (AR) ultimately relies on kidney biopsy; however, noninvasive tests predicting nonrejection would help avoid unnecessary biopsy. AR involves recruitment of leukocytes avid for fluorodeoxyglucose F(18) ((18) F-FDG), thus (18) F-FDG positron emission tomography (PET) coupled with computed tomography (CT) may noninvasively distinguish nonrejection from AR. From January 2013 to February 2015, we prospectively performed 32 (18) F-FDG PET/CT scans in 31 adult KTRs with suspected AR who underwent transplant biopsy. Biopsies were categorized into four groups: normal (n = 8), borderline (n = 10), AR (n = 8), or other (n = 6, including 3 with polyoma BK nephropathy). Estimated GFR was comparable in all groups. PET/CT was performed 201 ± 18 minutes after administration of 3.2 ± 0.2 MBq/kg of (18) F-FDG, before any immunosuppression change. Mean standard uptake values (SUVs) of both upper and lower renal poles were measured. Mean SUVs reached 1.5 ± 0.2, 1.6 ± 0.3, 2.9 ± 0.8, and 2.2 ± 1.2 for the normal, borderline, AR, and other groups, respectively. One-way analysis of variance demonstrated a significant difference of mean SUVs among groups. A positive correlation between mean SUV and acute composite Banff score was found, with r(2)  = 0.49. The area under the receiver operating characteristic curve was 0.93, with 100% sensitivity and 50% specificity using a mean SUV threshold of 1.6. In conclusion, (18) F-FDG PET/CT may help noninvasively prevent avoidable transplant biopsies in KTRs with suspected AR.

Treatment of a nephrotic syndrome by endoscopic removal of a villous adenoma of the duodenum

We report the case of a patient diagnosed with a villous adenoma of the duodenum showing high degree dysplasia who developed a nephrotic syndrome (NS) due to a membranous nephropathy (MN), demonstrated by renal biopsy. Only the endoscopic resection of the duodenal adenoma could control the NS. The first manifestation of a MN is often the development of a NS. Up to 20% of patients older than 65 years who develop a MN have cancer. Tumours most often identified are those of lung, prostate and digestive tract. A renal biopsy is required to identify this type of nephropathy. If a diagnosis of MN is made, an associated tumour should be looked for.

[A rare cause of acute renal failure, acute tubulo-interstitial nephritis]

We report the case of an acute renal failure due to an acute interstitial nephropathy (ATIN) induced by non steroidal anti-inflammatory drugs (NSAID). Even though this pathology is a rare cause of acute renal failure, it still requires special attention in view of the fact that it induces a high risk of acute morbidity but it also can evolve into chronic renal failure. Its differential diagnosis with other causes of acute renal failure becomes essential because of the different therapeutic care. In this article, we are going to briefly sum up the reasoning to adopt in order to diagnose an acute renal failure.

[Dapsone: an opportunity to spare corticoid use for Henoch-Schönlein treatment? A case report]

Dapsone is a sulfone essentially used to treat leprae. We describe, here, a somewhat rare indication of dapsone: corticoid sparing in the treatment of particular forms of Henoch-Schönlein.

[Benefits of mycophenolate mofetil in non-transplant kidney diseases]

Glomerular diseases remain frequent causes of end-stage renal failure. Immunosuppressive drugs in association with corticosteroids induce remission of proteinuria and stabilize renal function, as well as prevent relapses, but are responsible for severe potential side-effects: infections, secondary malignancies, sterility and alopecia, and even nephrotoxicity. Mycophenolate mofetil (MMF), a well-known drug in transplantation, presents interesting characteristics potentially useful in the treatment of glomerulopathies. Moreover, its side-effect profile is safer. The present review of the literature suggests that MMF is efficient for the treatment of glomerular disease, even if the results of the different studies remain limited and require further confirmation.

[Hypertension due to primary aldosteronism]

Primary aldosteronism is a rare cause of hypertension. However, its incidence seems to be underestimated. It is important to identify this syndrom since the disease is potentially curable. In the present paper, we depict different forms of primary aldosteronism as well as the diagnostic procedures. When the diagnosis is suspected (hypertension associated to spontaneous or diuretic-induced hypokaliemia), the more efficient screening test is the determination of the aldosteron/renin ratio. Saline infusion or posture tests can thereafter confirm the diagnosis. Differential diagnosis between bilateral and unilateral forms of primary aldosteronism can be made by CT-scanner and the response of aldosterone to the posture test. Such a complex assessment leads to the identification of patients who can be surgically treated. This treatment consists in a unilateral adrenalectomy which can be realised by laparoscopy.

Primary amyloidosis (AL) as a cause of nephrotic syndrome

AL amyloidosis is a rare systemic disease resulting from tissue accumulation of amyloid fibrils derived from monoclonal immunoglobulin light chains. It can disrupt the tissue architecture and consequently cause organ dysfunction. The prognosis is poor with a median survival of 13 months in untreated patients. By illustrating the case of a patient whose AL amyloidosis was detected after presenting a nephrotic syndrome, the characteristics of the disease are reviewed as well as diagnostic criteria and current available therapeutics.

Factors determining the percentage of hypochromic red blood cells in hemodialysis patients

Factors determining the percentage of hypochromic red blood cells determines iron status in hemodialysis patients.

BACKGROUND

Determination of the percentage of hypochromic red blood cells (RBC; %HYPO) has been advocated as a sensitive index of functional iron deficiency during erythropoietin (EPO) therapy in hemodialyzed patients.

METHODS

The significance of %HYPO in chronic renal failure was evaluated in 64 chronically hemodialyzed patients. The linear correlation was determined between %HYPO and 13 variables, including age, sex, weight, C-reactive protein (CRP), ferritin, transferrin (Tf), Tf saturation, soluble Tf receptor (sTfR), serum iron (SI), urea, parathormone, dialysis dose (Kt/V), dose of EPO administered (EPO), and absolute reticulocyte count. Multiple regression analyses were then performed to select the parameters that jointly provide the best prediction of %HYPO.

RESULTS

Univariate analysis showed significant correlations between %HYPO and iron parameters (sTfR, Tf saturation, SI, and ferritin, in decreasing order), EPO, reticulocyte count, and CRP. Multivariate analysis yielded an equation showing that the variation of %HYPO is essentially associated with the combined changes in sTfR, CRP, and EPO dosage.

CONCLUSIONS

%HYPO is a meaningful and inexpensive parameter that reflects the integrated effects of iron stores, inflammation, and erythropoietic stimulation on iron availability in hemodialyzed patients. Among iron exchange parameters, sTfR is the best predictor of %HYPO, followed by Tf saturation, SI, and ferritin.