The worldwide burden of kidney disease is rising, but public awareness remains limited, underscoring the need for more effective communication by stakeholders in the kidney health community. Despite this need for clarity, the nomenclature for describing kidney function and disease lacks uniformity. In June 2019, Kidney Disease: Improving Global Outcomes (KDIGO) convened a Consensus Conference with the goal of standardizing and refining the nomenclature used in the English language to describe kidney function and disease, and of developing a glossary that could be used in scientific publications. Guiding principles of the conference were that the revised nomenclature should be patient-centered, precise, and consistent with nomenclature used in the KDIGO guidelines. Conference attendees reached general consensus on the following recommendations: (i) to use “kidney” rather than “renal” or “nephro-” when referring to kidney disease and kidney function; (ii) to use “kidney failure” with appropriate descriptions of presence or absence of symptoms, signs, and treatment, rather than “end-stage kidney disease”; (iii) to use the KDIGO definition and classification of acute kidney diseases and disorders (AKD) and acute kidney injury (AKI), rather than alternative descriptions, to define and classify severity of AKD and AKI; (iv) to use the KDIGO definition and classification of chronic kidney disease (CKD) rather than alternative descriptions to define and classify severity of CKD; and (v) to use specific kidney measures, such as albuminuria or decreased glomerular filtration rate (GFR), rather than “abnormal” or “reduced” kidney function to describe alterations in kidney structure and function. A proposed 5-part glossary contains specific items for which there was general agreement. Conference attendees acknowledged limitations of the recommendations and glossary, but they considered standardization of scientific nomenclature to be essential for improving communication.

Hereditary kidney disease is a major cause of chronic kidney disease in childhood. Diagnosis of inherited kidney diseases in clinics is often complicated by the genetic heterogeneity of the pathology and clinical polymorphism of manifestations. Mass parallel sequencing with modern sequencing methods has been used in clinical practice over recent years. Up-to-date genetic testing has improved the diagnosis of various inherited diseases, which contributed to significant progress in the understanding of pathogenetic mechanisms, the identification of previously unrecognized phenotypes, and the reclassification of a number of kidney diseases, including COL4A-associated glomerulopathy and autosomal dominant tubulointerstitial diseases. The review presents various types of inheritance of monogenic diseases using the example of kidney pathology, grouped according to the OMIM medical database. The literature provides information concerning the up-to-date inherited of genetic and cytogenetic diagnostic, including Sanger sequencing, targeted multigene panels, technologies for massively parallel sequencing of the exome and genome, as well as chromosomal microarray analysis. The advantages and limitations of the molecular genetic diagnostic methods are highlighted in a comparative aspect. The indications for genetic testing in the case of suspicion of a hereditary nature of kidney pathology are presented, attention is drawn to the need to interpret the data of genetic studies in accordance with international and Russian national recommendations of professional communities of medical geneticists. The review an algorithm for genetic diagnostics with examples of clinical application in nephrological practice, including reasonable diagnostic and therapeutic approaches. Clinical situations in which genetic testing may allow patients to avoid kidney biopsy or immunosuppressive therapy with potential side effects are presented. It is shown that the use of genetic methods in pediatric nephrology is a necessary diagnostic tool for finding the causes of hereditary diseases, choosing pharmacotherapy, predicting the course of the disease, as well as medical and genetic counseling of patients' families and prenatal diagnosis of hereditary diseases.

Background: hyperparathyroidism (HPT) occurs in one-third to half of patients with chronic kidney disease (CKD) who have undergone kidney transplantation and have an adverse effect on the transplant period, increasing the risk of kidney transplant loss, bone fractures, cardiovascular events and deaths. Objectives: this review analyzes of risk factors for the development of HPT in patients with CKD after kidney transplantation and the efficacy and safety of paricalcitol for its prevention and treatment. Search methods: a literature review was conducted using the PubMed search engine in the electronic databases Medline, Embase, Cochrane Library, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. for June 2020. Results: the most important risk factors for persistence and de novo development of HPT after kidney transplantation are the presence of secondary HPT in the preoperative period and a decrease in renal transplant function in the development of chronic transplant nephropathy. Paricalcitol demonstrated an effective and safe correction of HPT in the pre-transplant period - in patients with CKD G3-G4 and dialysis patients, providing a reliable reduction in blood PTH without a significant change in serum concentrations of calcium and phosphorus. A series of small observational studies and a prospective, randomized, open-label study of Amer N. et al. from Mayo Clinic (USA) in patients after kidney transplantation with HPT showed high efficacy of paricalcitol in suppressing the parathyroid glands and good tolerance and safety in terms of the development of hypercalcemia, hyperphosphatemia and renal transplant function. Conclusions: paricalcitol is a reliable means of preventing the persistence of HPT in patients after kidney transplantation and for correction of secondary HPT in patients with a renal transplant function corresponding to CKD G3-G4. Further studies with a longer follow-up period are needed to evaluate the spectrum of additional (pleiotropic) effects of paricalcitol on the body and the function of the transplanted kidney.

Obstructive uropathy (OU) as a broad supranosological concept is characterized by a structural or functional obstacle to normal outflow of urine, sometimes leading to impaired renal function (obstructive nephropathy). The cause of obstruction may not always be diagnosed in pregnant women due to inability to use radiation diagnostics during gestation. In this regard, there are difficulties with the choice of treatment tactics, leading to a decision on the feasibility and, if necessary, the choice of a method for restoring the passage of urine in the urinary tract (UT), as well as the duration of the presence of drainage systems in them. The variability of possible urological and/or obstetric complications dictates the need to improve the diagnosis and to optimize the treatment of OU in pregnant women. One of the dangerous complications of UT obstruction is acute obstructive pyelonephritis - a disease caused by an infectious agent in violation of urodynamics, which requires urgent drainage of the upper UT with subsequent antibacterial therapy, while drainage is a vital operation. A feature of acute OU in pregnant women is polyethologicity: several mutually aggravating factors may participate in its occurrence and development: some congenital malformations (CM) with which woman enters pregnancy (anatomical disorders, including strictures of the ureter-vesical or pelvic-ureteral joints, vasoureteral conflict), asymptomatic stones of the calyx-pelvic system of the kidney, whose displacement can lead to urgent situation, compression of UT by a growing uterus, and, less often, a tumor. Another feature of OU is the possibility of similar clinical and laboratory symptoms in urological and obstetric complications. Clarification of the diagnosis, determination of indications for drainage of the UT, the correct choice of method for restoring the passage of urine, prevention and adequate treatment of acute obstructive pyelonephritis, timely removal or replacement of drains - all these therapeutic measures in certain clinical situations are debatable and require consensus understanding.

Kidney damage in ankylosing spondylitis (AS) id observed rather often. The diagnostic value of traditional markers of renal damage is not high that often leads to delayed diagnosis. Therefore, an active search for alternative methods is desirable. The aim: to assess the state of tubulointerstitium in patients with ankylosing spondylitis by measuring the level of urinary excretion of trefoil factor-3 (TFF-3). Patients and methods: urine samples of 50 patients (male/female - 37/13) were evaluated. The requirements for patients providing samples were: confirmed diagnosis of AS, age 18 and over and the absence of intercurrent diseases. Median age of patients was 39 [34; 56] years, duration of articular syndrome was 10 [7; 18] years, glomerular filtration rate (GFR) was 105 [83; 119] ml/min/1.73 m2. Patients received nonsteroidal anti-inflammatory drugs (NSAIDs), Disease Modifying Anti-Rheumatic Drugs (DMARDs) and tumor necrosis factor alpha inhibitors (TNFα inhibitors). TFF-3 level was measured by enzyme-linked immunosorbent assay. Urinary excretion was expressed as nanograms per mmol of urinary creatinine. The results were compared with the results of the control group. Results: the level of TFF-3 in patients without chronic kidney disease (CKD) was higher than in the control group: 53.4 [20.8; 105.7] vs. 23.3 [1.9; 62.9] ng/mmol respectively (р=0.02). A correlation with disease activity was found for BASDAI (rs=0.3, р<0.05) and ASDAS (rs=0.3, р<0.05). Marker values in patients receiving NSAIDs were higher compared with other type of therapy: 89.5 [39.8; 118.9] and 32.6 [13.5; 88.2] ng/mmol respectively (р=0.04). The level of TFF-3 did not depend on sex, age and AS duration. It also did not correlate with GFR and albuminuria. Conclusions: TFF-3 urinary excretion was higher in patients with AS compared with healthy individuals, as well as in patients receiving NSAIDs compared with TNFα inhibitors. Thus, the marker may be of interest for diagnosis in patients with pre-clinical tubulointerstitial damage, including those associated with the NSAIDs toxicity.

Background and Aims. The low dialysate sodium (NaD) reduces intradialytic weight gain (IDWG) and BP, which are associated with improved outcomes. However, the intervention also increases intradialytic hypotension (IDH) and reduces serum sodium (NaS), that are associated with increased mortality risk, so NaD should be individualized and brought closer to NaS. Predialysis NaS in HD-patients is considered constant but some observations contradict this statement. Method. Among 45 HD patients we monitored the following parameters: NaS, NaD, IDWG, intradialysis hyper- and hypotension and seizures, peri- and intradialysis blood pressure (BP), home BP estimated, estimated dry weight, UF, and HD frequency/duration for 24 months. Results. In 45 patients of 60 (34÷83) years old, median HD vintage 63 (29÷93) months the average NaS in 1048 probes was 137.1±2.8 mmol/l. Intra-individual NaS mean varied 132-141 mmol/l, CV median was 1.4%. The decreasing NaD trend (-0.12 mmol/l/year) was accompanied by more prominent trends in systolic BP (-3.3 mm Hg/year) and diastolic BP (-1.6 mm Hg/year); the IDH increased by 1.6 episodes/100HD/year (2.3±0.6 after excluding the trend). 73% of patients had no significant individual trend in NaS (<1 mmol/l/year), 18% had decreasing trend (-1.5 mmol/l/year); 9% - increasing trend (mean +1.6 mmol/l per year). Intraindividual variations in NaS had no link with mean NaS or mean NaS to dialysate gradient (NaG). We observed a significant variations in NaS only in patients with large variations of predialysis weight. Overall mean NaG was slightly positive (+0.15±3.0 mmol/l) while 58% of patients had negative or neutral NaG. The latter had lesser IDWG but no difference in IDH frequency. We evaluated the number of consecutive monthly predialysis NaS need to get acceptable estimation of mean two-year predialysis NaS: five values gave 96% hit in range ±1%. Conclusion. Serum sodium is stable over time in HD patients with the only exception of patients with large intraindividual predialysis weight variation and may be used for individualizing NaD.

Relevance: there is no consensus on which strategy of using intravenous iron for patients with CKD 5D is optimal in terms of the balance of benefit (achieving the target hemoglobin) and safety, and what is the role of serum ferritin in making decision to use iron. Aim: to assess the iron homeostasis in patients of the hemodialysis (HD) population of Saint Petersburg in the period 01.01.2017-01.01.2018; to investigate the association between high ferritin level and 1-year survival; to estimate changes in iron metabolism in 2017 vs. 2004. Methods: we studied the characteristics of 843 patients who received HD in 9 renal replacement therapy centers (RRT). The association of high ferritin and survival was evaluated using the Kaplan-Meier method. To compare the markers of the iron homeostasis in the HD patients in year 2017 versus 2004, we used our data published in 2005. Results: median ferritin was 351 [166; 634] µg/l, median annual iron dose was 1300 mg/year [400; 2400]; 34% of patients were in the target ferritin range 200-500 µg/l; 16% had ferritin >800. However, in some centers, the proportion of patients with ferritin >800 µg/l reached 38%, and those with >1200 ranged from 0 to 20.2%. Ferritin level did correlate with the Hb concentration. The survival rate tended to decrease with ferritin >800 µg/l (р=0.063, Wilcoxon-Breslow criterion), was lower for Hb <100 g/l vs. >100 (р<0.001), for CRP ≥10 mg/l vs. ≤4 (р<0.05), for albumin ≤37 g/l vs. >43 (р=0.001). In 2017, ferritin level increased slightly compared to 2004 (р=0.2). The median Hb was 110 [105; 115] g/l in 2017, compared to 95 [86; 106; р<0.001] in 2004. Conclusions: markers of the iron homeostasis in patients receiving HD in the RRT centers of St. Petersburg generally demonstrate a balanced approach to the use of intravenous iron. Aggressive tactics, aimed at ferritin levels >800 µg/l, should be avoided. There is a tendency of decreased survival rate for patients with ferritin >800 µg/l, and the dependence of survival rate on the level of Hb, C-reactive protein, and albumin. Comparison of the iron homeostasis markers in 2017 and 2004 showed a slight increase in ferritin level, higher proportion of patients reaching the target hemoglobin levels.

Aim: to conduct multivariate analysis of the risk factors for the development of postoperative acute kidney injury (AKI) after surgery for primary hyperparathyroidism (PHPT). Materials and methods: we performed a retrospective cohort study of 290 patients who underwent successful selective parathyroidectomy (PTx) for PHPT for the first time. AKI was defined according to KDIGO 2012 criteria. Results: the incidence of AKI in our cohort was 36.6%. We have grouped the risk factors as follows. Among the comorbid conditions, significant risk factors were age (ОR 1.05 [95%CI 1.02; 1.08] per a year, р=0.002), BMI (ОR 1.07 [95%CI 1.02; 1.13] per each kg/m2, р=0.005), anemia (yes/no ОR 3.38 [95%CI 1.38; 8.2], р=0.008), but not diabetes (yes/no ОR 0.96 [95%CI 0.42; 2.2], р=0.959), hypertension (yes/no ОR 1.29 [95%CI 0.62; 2.69], р=0.492), chronic kidney disease (yes/no ОR 1.06 [95%CI 0.5; 2.23], р=0.88). Among the PHPT-associated conditions, significant factors were: a history of fractures (yes/no ОR 5.6 [95%CI 1.4; 22.4], р=0.0015), bone mineral density value (BMD) (ОR 1.9 [95%CI 1.19; 3.03] per each SD, р=0.007). Among the "renal" risk factors - proteinuria (yes/no ОR 4.31 [95%CI 1.64; 11.35], р=0.003), eGFR (ОR 1.02 [95%CI 1.0; 1.03] per each ml/min/1.73 m2, р=0.042), use of ACE inhibitors/ARBs (ОR 2.84 [95%CI 1.58; 5.12], р=0.001), use of diuretics (ОR 2.23 [95%CI 1.11; 4.44], р=0.023), but not calcium channel blockers (ОR 1.75 [95%CI 0.88; 3.48], р=0.11), significantly increased risk of AKI. Intraoperative hypotension, minimal mean arterial pressure and hypotension duration did not increase the risk of AKI (р=0.945, 0.883 and 0.865, respectively). Among the specific PHPT-associated risk factors, significant were preoperative PTH level (ОR 1.03 [95%CI 1.01; 1.05] per each pmol/l, р=0.002), ∆ PTH (ОR 1.03 [95%CI 1.01; 1.06] per each pmol/l, р=0.003), but not preoperative serum ionized calcium level (ОR 0.4 [95%CI 0.06; 2.56] per each mmol/l, р=0.337) as well as the severity of its decrease (ОR 0.35 [95%CI 0.04; 3.53] per each mmol/l, р=0.352). Conclusions: the high risk of AKI after PTx for PHPT should be taken into account, risk factors of this complication should be identified and considered when planning PTx, special attention should be paid to modifiable risk factors: BMI, anemia, use of ACE inhibitors/ARBs, preoperative PTH level.

Drug-induced kidney injury represents a huge variety of conditions, directly or indirectly associated with drug toxicity and other drug adverse events. In this setting both acute kidney injury and chronic kidney disease, and acute injury on the top of chronic disease is common. Drug-induced kidney injury may result from the damage of all nephron segments: vasculature, glomeruli, tubules and interstitial space. Anti-cancer drugs include conventional, targeted (biological), and immunotherapy groups. The mechanisms of kidney injury associated with the anti-cancer drugs exposure include: 1) kidney hypoperfusion due to the gastrointestinal losses and volume depletion, resulting from the drug adverse events without direct nephrotoxicity; 2) endothelial dysfunction of kidney microvasculature, caused by anticancer-drugs adverse effects; 3) direct toxic tubular and glomerular endothelial damage; 4) anticancer-drug metabolites crystals intratubular deposition with tubular obstruction; 5) interstitial inflammation as a result of hypersensitivity drug reactions; and 6) immune-mediated glomerular and interstitial damage. Of note, the same anti-cancer drug may cause the damage of more than one segment of nephron, and the mechanisms of injury may interfere. Since novel biological target drugs and immunotherapy became widely implemented, and survival of patients with malignancies improved, anti-cancer drugs adverse kidney effects more and more influence long-term outcomes, and the knowledge of these effects turned to be mandatory. Recently emerged field of onco-nephrology, among other issues, study the anti-cancer drugs influence on the kidney health. In this review, we collected information about all classes of anti-cancer drugs in use, including novel target and immunotherapy agents, and highlighted pathogenesis, clinical and pathology presentation of different types of kidney injury, associated with different classes, groups, and particular anti-cancer drugs, and summarize the main data in the tables.

Atypical parathyroid adenoma is a rare cause of primary hyperparathyroidism (HPT). It can be diagnosed by morphological examination of the removed gland. In the published literature, We could not find any description of the primary HPT caused by atypical parathyroid adenoma in chronic kidney disease (CKD) in literature. Here we present a clinical observation of a young woman whose disease debuted with a hypertension (BP 210/130 mm Hg), proteinuria and high blood creatinine level (169 μmol/l, eGFR - 37 ml/min). Nephrobiopsy revealed focal global and segmental glomerulosclerosis. CKD stage 3 has been diagnosed, nephroprotective therapy was recommended. Blood biochemical examination after 8 years (before pregnancy): creatinine level - 156 μmol/l (eGFR 40 ml/min), ionized calcium and phosphorus 1.37 and 1.01 mmol/l, parathyroid hormone (PTH) 91 pg/ml. Neck ultrasound revealed no additional mass in the projection of the parathyroid glands (PG). After another year during pregnancy, creatinine was 137 μmol/l, total calcium corrected for serum albumin - 2.89 mmol/l, PTH - 47 pg/ml. CKD progressed after successful delivery, patient started of peritoneal dialysis treatment. PTH was 1613 pg/ml, calcium - 2.92-2.67 mmol/l, phosphorus - 2.12 mmol/l, alkaline phosphatase activity - 857 U/l (normal 3-258). Neck ultrasound a mass (26×15×13 mm) in the right lower PG. Selective parathyroidectomy was performed. Morphological study: a tumor node from the main cells with trabecular and perivascular rosette-like structures; a thick fibrous capsule with foci of tumor complexes; increased mitotic activity. Diffuse intense expression of PTH and proliferation index Ki-67=10% found in the immunohystochemical study. Conclusion: atypical parathyroid adenoma (pTisNx in accordance with American Joint Committee on Cancer, 2017). The protracted «hunger bone» syndrome was observed in the postoperative period. A brief clinical, biochemical and morphological characteristics of the atypical parathyroid adenoma are presented.

Kidney damage in patients with arthritis is one of the most formidable viscerites. Nephropathy in rheumatological diseases is diverse and can be a component of the main disease (for example, lupus nephritis in patients with systemic lupus erythematosus), and its complication (AA-amyloidosis in patients with rheumatoid arthritis) or a consequence of the use of drugs for treatment of rheumatological conditions. Kidney damage in patients with arthritis can include the glomerular and tubular compartments of the kidney, or both. Despite the importance of early diagnosis of kidney damage in patients with arthritis, this issue is not well understood. A possible reason for this is a small number of kidney biopsies in patients with these diseases. The presence of proteinuria or an increase of serum creatinine level often automatically considered as AA-amyloidosis, while other possible morphological variants are not considered. This leads to the detection of nephropathy in the later stages, which increases the risk of developing of chronic kidney disease (CKD) and worsens the overall prognosis in patients with arthritis. The management of such patients depends on the pathology pattern of nephropathy. In this regards, early screening of nephropathy and determination of indications for kidney biopsy recommended in such clinical situations. Treatment of such patients should be carried out by a multidisciplinary team of internists, nephrologists, and rheumatologists. We present description of two cases of nephropathy in patients with rheumatoid arthritis and ankylosing spondylitis, illustrated by kidney pathology; histological nuances and clinical features are discussed.