Pediatric Bilateral Hypoplastic Kidney Complicated With C1q Nephropathy: A Case Report.

Progressive kidney dysfunction is often observed in children with bilateral hypoplastic kidneys. While glomerulopathy can exacerbate hypoplastic kidney progression, only IgA nephropathy and post-streptococcal acute glomerulonephritis have been noted in such cases. Herein, we present a case of a four-year-old female patient with bilateral hypoplastic kidney, kidney dysfunction, and significant proteinuria (urinary protein/creatinine ratio > 1 g/gCr), prompting referral owing to persistent hematuria since two years of age. Enalapril was initiated; however, urinary findings exhibited no improvement despite stable symptoms and kidney function. Subsequently, a kidney biopsy was performed at six years of age, and C1q nephropathy was diagnosed. Given the presence of only mild mesangial proliferation, steroids were not administered; enalapril treatment was continued. By seven years of age, the patient's hematuria had resolved, and proteinuria levels had decreased. On the latest follow-up at 12 years of age, kidney function was preserved with only mild proteinuria. This case report highlights the favorable prognosis of asymptomatic C1q nephropathy characterized by mild mesangial proliferation, even in patients with hypoplastic kidneys, renal dysfunction, and significant proteinuria. It emphasizes the significance of timely pathological evaluation for guiding appropriate interventions in such patients.

[Clinical and morphological correlations in patients with lupus nephritis: a retrospective study].

AIM: To analyze associations between clinical and morphological features of kidney involvement in patients with systemic lupus erythematosus. MATERIALS AND METHODS: In the retrospective cohort study, we enrolled adult (≥18 years) patients with morphologically proven lupus nephritis (LN) stratified according to the ISN/RPS classification. Systemic lupus erythematosus was classified in accordance with ACR/EULAR classification criteria (2019). Antiphospholipid syndrome was diagnosed according to the 2006 classification criteria. Disease activity was assessed with SELENA-SLEDAI score. RESULTS: We enrolled 62 patients with LN, among them 84% were females. Median age of SLE onset was 23 (16,3; 30,8) years. In all cases kidney involvement was accompanied by extrarenal manifestations, among which joint (82%), skin (57%) and hematological involvement (68%) was the most common. LN class I was proven in one patient, class II - in three patients, class III - in 24, including III+V in seven, class IV - in 18, including IV+V in two, class V - in 13, class VI - in three patients. APS nephropathy was diagnosed in 4 (6.5%) of patients with LN. The most common clinical manifestation was proteinuria (85%), however its prevalence, level and the frequency of nephrotic syndrome showed no significant differences between the LN classes. LN III/IV±V was characterized by the highest levels of serum creatinine (and the lowest eGFR) at the time of biopsy. CONCLUSION: LN is characterized by the high heterogeneity of the clinical and morphological manifestations, which makes LN class prediction impossible without kidney biopsy.

A case report of dipeptidyl peptidase 4 inhibitor-related kidney disease combined with renal cancer.

A kidney biopsy was performed in a 64-year-old woman with type 2 diabetes mellitus and less than 1 g of proteinuria who rapidly progressed to end-stage renal failure after approximately 2 years of treatment with two dipeptidyl peptidase 4 (DPP-4) inhibitors for type 2 diabetes mellitus. The biopsy revealed not only a coincidental diagnosis of renal cell carcinoma, which was not evident on pre-biopsy computed tomography, but also severe thrombotic microangiopathy (TMA)-like glomerular endothelial cell damage in the noncancerous areas. These results suggest that DPP4 inhibitors may have been involved in two kidney diseases.

Role of Desmopressin Acetate before Percutaneous Ultrasound-Guided Kidney Biopsy in Patients with Kidney Dysfunction.

Background: The most common complication of percutaneous kidney biopsy is bleeding, which can be seen in up to one-third of cases. The aim of this study was to evaluate the effect of prebiopsy administration of intranasal desmopressin acetate in reducing the incidence of biopsy-related bleeding complications. Materials and Methods: This was a prospective randomized double-blind pilot study conducted at our center from January 2021 to September 2022. Consecutive adult patients who underwent native percutaneous kidney biopsy with an estimated glomerular filtration rate (eGFR) ≤45 ml/min/1.73 m2 were randomized into a placebo (saline intranasal spray) group versus intranasal desmopressin group. The bleeding complications were compared between the two groups. Results: A total of 80 patients who underwent kidney biopsy at our center from January 2021 to September 2022 with eGFR ≤45 ml/min/1.73 m2 were included (40 patients in desmopressin group and 40 patients in non-desmopressin group) in the study. The mean age of the patients was 44 ± 12 years with a mean eGFR of 20.82 ± 12.64 ml/min/1.73 m2. Intranasal desmopressin administration before kidney biopsy was associated with a significantly higher number of minor bleeding complications (P = 0.02) and no significant reduction in major complications (P = 0.15) when compared with a group that did not receive desmopressin. Other complications like hypotension, flushing, and vasovagal syncope were not statistically significantly associated with the use of desmopressin. Conclusion: Our study did not find any utility of prophylactic desmopressin use before kidney biopsy in patients with kidney dysfunction.

Proposal of a novel cardiovascular risk prediction score in lupus nephritis.

Introduction: Patients with systemic lupus erythematosus are prone to develop cardiovascular disease (CVD), and have increased morbidity and mortality. Methods: We conducted a retrospective analysis on lupus nephritis patients to assess the occurrence and predictors of major adverse cardiovascular events (MACE). Data were collected from patients who underwent kidney biopsy between 2005 and 2020. Statistical analysis was performed to unveil correlations. Results: 91 patients were analyzed in this period, with a mean age of 37.3 ± 12.3 years and 86% being female. The mean follow-up time was 62 ± 48 months. 15.38% of the patients underwent at least one MACE. Two patients deceased of CVD. Increased age (35.81 ± 11.14 vs 45.5 ± 15.11 years, p=0.012) entailed a higher occurrence of MACEs. Neutrophil count (5.15 ± 2.83 vs 7.3 ± 2.99 Giga/L, p=0.001) was higher, whereas diastolic blood pressure (DBP) was lower (89.51 ± 10.96 vs 78.43 ± 6.9 mmHg, p<0.001) at the time of the biopsy in patients with MACE. Age, neutrophil count, and DBP proved to be independent predictors of MACEs. We propose a new model (CANDE - Cardiovascular risk based on Age, Neutrophil count, and Diastolic blood pressure Estimation score) calculated from these variables, which predicts the probability of MACE occurrence. Conclusion: This study underscores the importance of actively screening for cardiovascular risks in this vulnerable patient population. Age, neutrophil count, and diastolic blood pressure have been established as independent risk factors for MACE in lupus nephritis. The CANDE score derived from these parameters may serve as a prompt, cost-effective, and easily accessible estimation tool for assessing the likelihood of major adverse cardiovascular risk. These findings emphasize the necessity for comprehensive management strategies addressing both immune dysregulation and cardiovascular risk factors in systemic lupus erythematosus to mitigate adverse outcomes.

The validity of pathology codes for biopsy-confirmed kidney disease in the Danish National Patobank.

Background: This study validates the application of Systematized Nomenclature of Medicine second edition (SNOMED II) codes used to describe medical kidney biopsies in Denmark in encoded form, aiming to support robust epidemiological research on the causes, treatments and prognosis of kidney diseases. Methods: Kidney biopsy reports from 1 January 1998 to 31 December 2018 were randomly extracted from the Danish National Patobank, using SNOMED codes. A 5% sample was selected, and nephrologists assessed the corresponding medical records, assigning each case the applied clinical diagnoses. Sensitivity, specificity, positive predictive values (PPV), negative predictive values and Cohen's kappa coefficient for the retrieved SNOMED codes were calculated. Results: A total of 613 kidney biopsies were included. The primary clinical disease groups were glomerular disease (n = 368), tubulointerstitial disease (n = 67), renal vascular disease (n = 51), diabetic nephropathy (n = 51) and various renal disorders (n = 40). Several SNOMED codes were used to describe each clinical disease group and PPV for the combined SNOMED codes were high for glomerular disease (94%), diabetic nephropathy (85%) and systemic diseases affecting the kidney (96%). Conversely, tubulointerstitial disease (62%), renal vascular disease (60%) and other renal disorders (17%) showed lower PPV. Conclusions: SNOMED codes have a high PPV for glomerular diseases, diabetic nephropathy and systemic diseases affecting the kidney, in which they could be applied for future epidemiological research.

Monoclonal gammopathy of renal significance from the perspective of nephrologists.

Kidney disease is a frequent complication of multiple myeloma and other malignancies associated with monoclonal gammopathies. Additionally, dysproteinemia-related kidney disease can occur independently of overt multiple myeloma or hematologic malignancies. Monoclonal gammopathy of renal significance (MGRS) is a spectrum of disorders in which a monoclonal immunoglobulin produced by a benign or premalignant B-cell or plasma cell clone causes kidney damage. MGRS-associated renal disease manifests in various forms, including immunoglobulin-associated amyloidosis, monoclonal immunoglobulin deposition diseases (light chain, heavy chain, and combined light and heavy chain deposition diseases), proliferative glomerulonephritis with monoclonal immunoglobulin deposits, C3 glomerulopathy with monoclonal gammopathy, and light chain proximal tubulopathy. Although MGRS is a nonmalignant or premalignant hematologic condition, it has significant renal implications that often lead to progressive kidney damage and, eventually, end-stage kidney disease. This review discusses the epidemiology, pathogenesis, and management of MGRS and focuses on the perspective of nephrologists.

Lupus nephritis kidney biopsy characteristics and preterm birth.

Individuals with lupus nephritis (LN) are at high risk of adverse maternal and fetal outcomes in pregnancy. Outside of pregnancy, proliferative lesions on kidney biopsies are associated with disease progression, but these have not been consistently associated with increased risk in pregnancy. This retrospective, single-center study examines how histologic findings, the timing from kidney biopsy to pregnancy, and the clinical features in the first trimester are associated with preterm birth among individuals with LN. Among 35 deliveries in 31 women, the mean gestational age at delivery was 33.8 weeks. The presence of a urine protein-to-creatinine ratio >0.5 g/g in the first trimester was associated with preterm delivery (81% vs. 36%, p = 0.04). Preterm birth was more common in individuals with glomerular crescents on biopsy (89% in those with >20% crescents vs. 50% in those with <20%, p = 0.06). A pregnancy occurring within 2 years after a kidney biopsy was more likely to result in preterm birth than if the biopsy was performed more than 2 years prior to conception (82% vs. 23%, p = 0.01). The time from diagnostic biopsy may be a surrogate for disease activity, and a 2-year delay from biopsy might allow sufficient time to achieve disease remission. Overall, these data could aid family planning discussions and promote preconception disease optimization for patients and their providers.

Straightforward and immediate ultrasound-guided kidney biopsy using a guide needle technique to get adequate tissue with reduced procedural time.

BACKGROUND: A streamlined and effective renal biopsy technique is essential for all nephrologists, particularly those who are less experienced, such as residents. Herein, we report the efficacy of a Straightforward and Immediate ultrasound-guided kidney biopsy using a Guide Needle (SIGN) technique, which allows operators to insert a biopsy gun through a guide needle placed into the fascia of the posterior abdominal wall. METHODS: A retrospective cross-sectional study was conducted at a nephrology training institution to compare the time spent on the procedure and the number of glomeruli obtained between a group using the SIGN (n = 81) and a group using the conventional ultrasound-guided kidney biopsy technique with a needle guide device (n = 143). RESULTS: The median procedure time in the SIGN group (2 min, interquartile range [IQR]: 1-3 min) was significantly shorter than that in the conventional group (3 min, IQR: 2-4 min) (P < 0.001). Multivariable linear regression and logistic regression analyses adjusted for covariates, including operators (board-certificated nephrologists or nephrology residents), showed that the use of the SIGN technique was independently associated with a high number of glomeruli obtained and a procedure time above 2 min as the median value (odds ratio: 0.17, 95% confidence interval CI 0.09-0.34). The prevalence of complications was comparable between the two groups (P = 0.681). CONCLUSION: The SIGN technique reduces the procedure time and obtains adequate biopsy tissue regardless of the operator's experience. SIGN can be applied in nephrology training programs and used as a standard biopsy technique.

Long-term clinicopathological characteristics of TAFRO syndrome and its relapse: a case series study.

Introduction: This study aimed to analyze the clinical course of TAFRO syndrome in patients through extended follow-up, focusing on recurrent cases and long-term remission. Methods: This was a retrospective case series study. We assessed the clinical course of patients diagnosed with TAFRO syndrome between January 2012 and September 2022 at Toranomon Hospital or Toranomon Hospital Kajigaya, excluding those patients who died during the initial hospitalization. Results: Twelve patients were included. Baseline characteristics, laboratory findings, treatment modalities, and outcomes were assessed. During the median follow-up period of 1474 days, two patients experienced recurrence following a reduction in tocilizumab (TCZ) dose, whereas two achieved remission for >400 days without TCZ treatment. The remaining eight patients maintained remission under the continued TCZ therapy. Recurrence diagnosis was complicated by the non-simultaneous presentation of the five manifestations of TAFRO syndrome. The patients who experienced recurrence showed milder manifestations and faster recovery than the initial onset. Glomerular endotheliopathy was evident in kidney biopsies during recurrence, which was similar to the initial presentation. In a case where only inflammation preceded other manifestation, a kidney biopsy was pivotal in distinguishing TAFRO syndrome relapse from other inflammatory conditions such as infection. Pretreatment serum IL-6 levels were within the reference range only in patients who experienced long-term remission without TCZ treatment. Conclusions: This is the first study to perform kidney biopsies on recurrent TAFRO cases, highlighting recurrence after TCZ dosage reduction, non-simultaneous manifestation of symptoms, the utility of kidney biopsies in recurrence diagnosis, and potential non-IL-6 pathogenesis factors. Pretreatment serum IL-6 levels may help identify patients suitable for maintenance therapy without TCZ. Further investigation is warranted to identify stratified treatment approaches based on individual etiologic factors.

Renal arterial resistive index as a prognostic marker in lupus nephritis patients.

INTRODUCTION: Lupus nephritis (LN) is known to be one of the most serious complications of SLE and it is a major predictor of poor prognosis. Despite the improvement in understanding the pathophysiology of lupus nephritis and greater improvement in diagnostic approaches, lupus nephritis patients have poorer outcomes. OBJECTIVES: Study the relation between renal resistive index (RRI) and renal function and histopathological parameters in lupus nephritis (LN) patients. Also to investigate the usefulness of RRI in predicting response to treatment. PATIENTS AND METHODS: This study included 126 patients who were split into two groups (group 1: 101 LN patients and group 2: 25 SLE patients without renal affection); and 100 healthy controls (group 3). The RRI was measured for all participants through a colored Doppler ultrasound examination. LN patients underwent renal biopsy and received their therapy and were followed up for 6 months. RESULTS: The RRI was significantly greater in the LN group (mean±SD; 0.64±0.07) than in SLE patients without nephritis (0.5884±0.04) (P<0.0001). The RRI was greater in LN class IV (P<0.0001). RRI significantly correlated with the chronicity index (r=0.704, P<0.0001), activity index (r=0.310, P=0.002), and serum creatinine (r=0.607, P<0.0001) and negatively correlated with eGFR (r=-0.719, P<0.0001). Almost eighty-five percent (84.8%) of LN patients responded to induction therapy. RRI was significantly greater in the nonresponder group (mean±SD, 0.73±0.02) than that in the responder group (0.63±.07) (P<0.0001). All non-responders to induction therapy while only 29.8% of responders had an RRI of ˃0.7. RRI, according to regression analysis was a significant predictor of response to treatment in LN patients. CONCLUSION: RRI was significantly greater in the LN group and significantly correlated with kidney function and histopathological parameters. RRI can predict response to induction therapy in LN patients.

Smartphone-based machine learning model for real-time assessment of medical kidney biopsy.

Background: Kidney biopsy is the gold-standard for diagnosing medical renal diseases, but the accuracy of the diagnosis greatly depends on the quality of the biopsy specimen, particularly the amount of renal cortex obtained. Inadequate biopsies, characterized by insufficient cortex or predominant medulla, can lead to inconclusive or incorrect diagnoses, and repeat biopsy. Unfortunately, there has been a concerning increase in the rate of inadequate kidney biopsies, and not all medical centers have access to trained professionals who can assess biopsy adequacy in real time. In response to this challenge, we aimed to develop a machine learning model capable of assessing the percentage cortex of each biopsy pass using smartphone images of the kidney biopsy tissue at the time of biopsy. Methods: 747 kidney biopsy cores and corresponding smartphone macro images were collected from five unused deceased donor kidneys. Each core was imaged, formalin-fixed, sectioned, and stained with Periodic acid-Schiff (PAS) to determine cortex percentage. The fresh unfixed core images were captured using the macro camera on an iPhone 13 Pro. Two experienced renal pathologists independently reviewed the PAS-stained sections to determine the cortex percentage. For the purpose of this study, the biopsies with less than 30% cortex were labeled as inadequate, while those with 30% or more cortex were classified as adequate. The dataset was divided into training (n=643), validation (n=30), and test (n=74) sets. Preprocessing steps involved converting High-Efficiency Image Container iPhone format images to JPEG, normalization, and renal tissue segmentation using a U-Net deep learning model. Subsequently, a classification deep learning model was trained on the renal tissue region of interest and corresponding class label. Results: The deep learning model achieved an accuracy of 85% on the training data. On the independent test dataset, the model exhibited an accuracy of 81%. For inadequate samples in the test dataset, the model showed a sensitivity of 71%, suggesting its capability to identify cases with inadequate cortical representation. The area under the receiver-operating curve (AUC-ROC) on the test dataset was 0.80. Conclusion: We successfully developed and tested a machine learning model for classifying smartphone images of kidney biopsies as either adequate or inadequate, based on the amount of cortex determined by expert renal pathologists. The model's promising results suggest its potential as a smartphone application to assist real-time assessment of kidney biopsy tissue, particularly in settings with limited access to trained personnel. Further refinements and validations are warranted to optimize the model's performance.

Overlap of membranous nephropathy and IgA nephropathy in a patient with Kimura's disease: a case report and literature review.

Introduction: Kimura's disease (KD) is a rare chronic inflammatory disorder characterized by subcutaneous lymphoid hyperplasia with peripheral eosinophilia. Kidney involvement is reported in 15%-18% of adult patients with KD, in many cases as nephrotic syndrome. We present a case of overlapping membranous nephropathy and IgA nephropathy associated with KD. Case report: A 27-year-old man was admitted with a history of bilateral leg edema for the last 2 months and concomitant progressive increase of cervical mass and fever. Laboratory findings were as follows: peripheral leukocyte count, 10,080/mm³; eosinophils, 3,200/mm³ (31.7%); serum creatinine, 0.83 mg/dL; and eGFR: 140 mL/min per 1.73 m2. Urinalysis revealed the presence of hematuria and proteinuria and the following results: 24-h proteinuria, 12.9 g; serum albumin, 1.3 g/dL; and elevated IgE level, 750 kU/L. Serologies for hepatitis B, hepatitis C, HIV, and VDRL were all negative. Complement C3 and C4 levels were normal. No monoclonal protein was detected in blood and urine. Parasite infestation was discarded. A biopsy of the cervical lymph node revealed eosinophilic lymphoid hyperplasia, suggesting KD. A kidney biopsy revealed findings consistent with the overlapping of membranous nephropathy with IgA nephropathy. The patient was treated for KD with prednisone 1 mg/kg/d with progressive dose tapering and posterior association of methotrexate 15 mg/week. A renin-angiotensin system inhibitor was prescribed for nephrotic syndrome. The cervical mass regressed, and proteinuria achieved partial remission, with an increase in serum albumin level and normalization of eosinophils and IgE levels. Conclusion: Although uncommon, kidney involvement must be considered in patients with KD. Glomerular diseases are the most frequent form of kidney injury.

Rare case of aspergillosis with solitary renal involvement: micro-fungus ball in graft kidney.

Kidney transplant recipients are at an increased risk of various infections due to immunosuppressive medications. Among them, fungal infections are associated with high mortality and morbidity. This report presents the case of a 54-year-old kidney-transplant recipient who was diagnosed with aspergillosis with solitary renal involvement. He was diagnosed by kidney biopsy with the micro-fungus ball. In the biopsy sample, consisting mostly of the medulla, a small focus consisting of an aggregate of fungal microorganisms was identified. The micro-fungus ball, which was also present in serial sections, was characterized by slight pigmentation and septate hyphae with acute angle branching, highlighted by the silver stains. The patient was examined for invasive fungal infection. In CT scans, there were no signs of invasive fungal infection. Due to the unexpected kidney biopsy finding, the patient underwent a repeat allograft biopsy from which a culture was sent. Aspergillus fumigatus complex was detected in tissue fungal culture of this repeat biopsy. The patient was started on voriconazole treatment and was successfully treated. It should be kept in mind that fungal infections with isolated subtle renal involvement may be possible in KTR under immunosuppressive treatment without an obvious fungal focus being demonstrated by imaging methods.

Controversy between biopsy and risk in children with proteinuria: is there a paradigm war?

BACKGROUND: Proteinuria is a prevalent symptom of pediatric nephrology, while kidney biopsy remains the gold standard for kidney tissue analysis, and it is currently controversial. We report the rare case that the mutation in the AMN gene was considered to cause chronically isolated proteinuria and also suggest that renal biopsy should be chosen with caution in children with chronic isolated non-nephrotic levels of proteinuria and that genetic testing may be feasible for the early precise diagnosis. CASE PRESENTATION: A 35-month-old boy presented with excessive urine foaming for more than half a month; his proteinuria was considered non-nephrotic range and urine protein electrophoresis was suggestive of mixed proteinuria; other than that, the investigations are non-specific. Given the child's chronic isolated proteinuria and good renal function, we chose to refine the genetic test rather than a renal biopsy; a compound heterozygous variant was found in the AMN gene of this child which was caused by a point mutation in the father, and a partial chromosomal deletion in the mother. CONCLUSIONS: Cubilin(encoded by CUBN), amnionless(encoded by AMN), and megalin form a multiligand receptor complex; CUBN or AMN gene variants have been implicated as a hereditary cause of megaloblastic anemia, proteinuria, and neurological impairment. In the past few decades, chronic isolated proteinuria caused by CUBN gene variants is benign, non-progressive, and has normal renal function. However, the child is the first reported case of isolated proteinuria of AMN gene mutation, indicating that the earlier diagnostic genetic sequencing in an otherwise well, not nephrotic proteinuria child may be a convenient, cost-effective, and harmless option, challenging the traditional paradigm.

Infection-Related Glomerulonephritis Due to Subacute Bacterial Endocarditis in the Aortic Valve: A Case Report.

Infection-related glomerulonephritis (IRGN) is a rare but severe complication of bacterial infections, including subacute bacterial endocarditis (SBE). We present a case of a 15-year-old male with bilateral lower limb swelling, facial puffiness, frothy urine, and dyspnea. Laboratory investigations revealed abnormal kidney function tests and imaging studies confirmed infective endocarditis. Blood cultures isolated Burkholderia cepacia and methicillin-resistant coagulase-negative Staphylococcus. Kidney biopsy confirmed immune complex-mediated glomerulonephritis. The patient received multidisciplinary care, including respiratory support, hemodialysis, antibiotics, and blood transfusion. This case highlights the importance of recognizing and promptly managing IRGN secondary to SBE to prevent irreversible renal damage and systemic complications.

A preliminary probabilistic nomogram model for predicting renal arteriolar damage in IgA nephropathy from clinical parameters.

Background: IgA nephropathy (IgAN) is a significant contributor to chronic kidney disease (CKD). Renal arteriolar damage is associated with IgAN prognosis. However, simple tools for predicting arteriolar damage of IgAN remain limited. We aim to develop and validate a nomogram model for predicting renal arteriolar damage in IgAN patients. Methods: We retrospectively analyzed 547 cases of biopsy-proven IgAN patients. Least absolute shrinkage and selection operator (LASSO) regression and logistic regression were applied to screen for factors associated with renal arteriolar damage in patients with IgAN. A nomogram was developed to evaluate the renal arteriolar damage in patients with IgAN. The performance of the proposed nomogram was evaluated based on a calibration plot, ROC curve (AUC) and Harrell's concordance index (C-index). Results: In this study, patients in the arteriolar damage group had higher levels of age, mean arterial pressure (MAP), serum creatinine, serum urea nitrogen, serum uric acid, triglycerides, proteinuria, tubular atrophy/interstitial fibrosis (T1-2) and decreased eGFR than those without arteriolar damage. Predictors contained in the prediction nomogram included age, MAP, eGFR and serum uric acid. Then, a nomogram model for predicting renal arteriolar damage was established combining the above indicators. Our model achieved well-fitted calibration curves and the C-indices of this model were 0.722 (95%CI 0.670-0.774) and 0.784 (95%CI 0.716-0.852) in the development and validation groups, respectively. Conclusion: With excellent predictive abilities, the nomogram may be a simple and reliable tool to predict the risk of renal arteriolar damage in patients with IgAN.