Reversible renal failure in the nephrotic syndrome

Successful treatment of peritoneal dialysis for two patients with refractory nephrotic syndrome and acute kidney injury: a case report

Two patients with refractory nephrotic syndrome were treated with peritoneal dialysis (PD) for diuretic resistance, anasarca and acute kidney injury. Following PD, their fluid overload was promptly alleviated, accompanied by an increase in urine volume and an improvement in renal function. PD as an adjuvant approach enabled them to resume corticosteroids and immunosuppressive agents. Eventually, both patients could be withdrawn from PD and achieved remission of proteinuria.

Serum free fatty acid elevation is related to acute kidney injury in primary nephrotic syndrome

The aim of this research was to examine the clinical characteristics of acute kidney injury (AKI) in primary nephrotic syndrome (NS) and discuss the relationship between serum lipids and AKI. A total of 1028 patients diagnosed with primary NS with renal biopsy results were enrolled in this study. The patients were divided into AKI (n = 81) and non-AKI (n = 947) groups, and their characteristics were compared using a propensity score analysis for the best matching. Serum free fatty acid (FFA) was an independent predictor for AKI in the postmatch samples (p = 0.011). No significant difference in FFA levels was observed among AKI stages or different pathological types in the AKI and non-AKI groups. The AUC (area under the ROC curve) was 0.63 for FFA levels to distinguish AKI. In primary NS, elevated FFA levels tend to be related to a high risk of AKI. FFAs have diagnostic value and may serve as biomarkers for AKI in NS.

Prediction model of renal function recovery for primary membranous nephropathy with acute kidney injury

Background and objectives

The clinical and pathological impact factors for renal function recovery in acute kidney injury (AKI) on the progression of renal function in primary membranous nephropathy (PMN) with AKI patients have not yet been reported, we sought to investigate the factors that may influence renal function recovery and develop a nomogram model for predicting renal function recovery in PMN with AKI patients.

Methods

Two PMN with AKI cohorts from the Nephrology Department, the First Affiliated Hospital of Wenzhou Medical University during 2012–2018 and 2019–2020 were included, i.e., a derivation cohort during 2012–2018 and a validation cohort during 2019–2020. Clinical characteristics and renal pathological features were obtained. The outcome measurement was the recovery of renal function within 12 months. Lasso regression was used for clinical and pathological features selection. Prediction model was built and nomogram was plotted. Model evaluations including calibration curves were performed.

Result

Renal function recovery was found in 72 of 124 (58.1%) patients and 41 of 72 (56.9%) patients in the derivation and validation cohorts, respectively. The prognostic nomogram model included determinants of sex, age, the comorbidity of hypertensive nephropathy, the stage of glomerular basement membrane and diuretic treatment with a reasonable concordance index of 0.773 (95%CI,0.716–0.830) in the derivation cohort and 0.773 (95%CI, 0.693–0.853) in the validation cohort. Diuretic use was a significant impact factor with decrease of renal function recovery in PMN with AKI patients.

Conclusion

The predictive nomogram model provides useful prognostic tool for renal function recovery in PMN patients with AKI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02882-9.

Disease-Associated Systemic Complications in Childhood Nephrotic Syndrome: A Systematic Review

Introduction

Nephrotic syndrome (NS) is one of the most common childhood kidney diseases. During the active phase, the disease pathogenesis affects various biological functions linked to loss of proteins negatively, which can result in systemic complications. Complications of childhood NS are divided into two categories: disease-associated complications and drug-associated complications. However, complications in pediatric patients with NS, especially disease-associated complications are still limited. Although reported in the literature, information is not comprehensive and needs to be updated. This study aimed to systematically assess systemic complications in children with NS, especially disease-associated complications, to better understand how they impact outcomes.

Methods

We conducted a systematic search of several databases: BioMed Central Pediatrics, PubMed, Google Scholar, the National Library of Medicine, Cochrane Library, CINAHL/EBSCO, British Medical Journal, Science Direct, Scopus, and Elsevier’s ClinicalKey. We followed the PRISMA guidelines to plan, conduct, and report this review. We used the Joanna Briggs Institute’s critical appraisal tools for assuring the quality of the journal articles that were chosen.

Results

Eleven articles concerning complications in childhood NS were analyzed. Systemic disease-associated complications in covered were cardiovascular complications, infections, thyroid-hormone complication, kidney complications, and oral health complications.

Conclusion

NS is marked by heavy proteinuria, hypoalbuminemia, edema, and hyperlipidemia, which can result in systemic disease-associated complications. Cardiovascular complications, infections, thyroid-hormone complications, kidney complications, and oral health complications are the main systemic complications in childhood NS. It is essential that health-care providers prevent these complications for proper maintenance of patients’ health.

Effectiveness and safety of rehabilitation on minimal change nephrotic syndrome in remission for elderly patients with low activity of daily living: a case report

There are few reports on the rehabilitation of elderly patients with minimal change nephrotic syndrome (MCNS). The purpose of this case study was to evaluate the efficacy and safety of rehabilitation for an elderly patient with MCNS in remission. The patient was an 86-year-old woman. She was admitted to the hospital with a diagnosis of MCNS, and steroid treatment was initiated. She was weaned from dialysis 2 weeks later; however, her activities of daily living (ADL) decreased, and she developed disuse syndrome. After rehabilitation, the patient's ADL, maximum hand grip strength, and gait function improved. There was no recurrence of weight gain or increased proteinuria during rehabilitation, but the estimated glomerular filtration rate decreased. This case suggests that rehabilitation for elderly patients with MCNS in remission can be effective for physical and ADL functions without relapse of MCNS. The effect of exercise therapy on the relationship between exercise therapy and renal function needs to be further investigated by collecting more cases.

Clinical features of acute kidney injury in patients with nephrotic syndrome and minimal change disease: a retrospective, cross-sectional study

Background:

Minimal change nephropathy (MCD) is a common pathological type of nephrotic syndrome and is often associated with acute kidney injury (AKI). This study aimed to investigate the clinical characteristics and related factors of AKI in patients with MCD and nephrotic syndrome.

Methods:

Patients from Chinese People's Liberation Army General Hospital who were diagnosed with pathological renal MCD with clinical manifestations of nephrotic syndrome were included from January 1, 2013 to December 31, 2017. Patients diagnosed with membranous nephropathy (MN) by renal biopsy from January 1, 2013 to December 31, 2017 are included as a control population. We retrospectively analyzed the clinical and pathological characteristics of patients as well as the percentages and clinical characteristics of AKI in different age groups. We assessed the correlation of pathological characteristics with serum creatinine using multivariate linear regression analysis.

Results:

A total of 367 patients with MCD were included in the analysis, with a sex ratio of 1.46: 1 (male: female) and an age range of 6 to 77 years. Among all the patients, 109 developed AKI (29.7%), and of these patients, 85 were male (78.0%). In the 586 patients with MN, 27 (4.6%) patients developed AKI. The percentage of AKI in MCD patients was significantly higher than that in MN patients (χ² = 41.063, P < 0.001). The percentage of AKI increased with age in the MCD patients. The percentage of AKI in patients aged 50 years or older was 52.9% (46/87), which was significantly higher than that [22.5% (63/280)] in patients under 50 years (χ² = 6.347, P = 0.013). We observed statistically significant differences in age (43 [27, 59] years vs. 28 [20, 44] years, Z = 5.487, P < 0.001), male (78.0% vs. 51.4%, χ² = 22.470, P < 0.001), serum albumin (19.9 ± 6.1 g/L vs. 21.5 ± 5.7 g/L, t = 2.376, P = 0.018), serum creatinine (129.5 [105.7, 171.1] μmol/L vs. 69.7 [57.7, 81.9] μmol/L, Z = 14.190, P < 0.001), serum urea (10.1 [6.2, 15.8] mmol/L vs. 4.7 [3.6, 6.4] mmol/L, Z = 10.545, P < 0.001), IgE (266.0 [86.7, 963.0] IU/ml vs. 142.0 [35.3, 516.5] IU/ml, Z = 2.742, P = 0.007), history of diabetes (6.4% vs. 1.2%, P = 0.009), and history of hypertension (23.9% vs. 5.1%, χ² = 28.238, P < 0.001) between the AKI group and the non-AKI group. According to multivariate linear regression analysis, among the renal pathological features analyzed, renal tubular epithelial cell damage (β = 178.010, 95% CI: 147.888−208.132, P < 0.001) and renal interstitial edema (β = 28.833, 95% CI: 11.966−45.700, P = 0.001) correlated with serum creatinine values.

Conclusions:

The percentage of AKI in MCD patients is significantly higher than that in MN patients. Patients over 50 years old are more likely to develop AKI. Renal tubular epithelial cell injury and renal interstitial edema may be the main pathological lesions that are associated with elevated serum creatinine in patients with MCD.

Comparison of treatment options in adults with frequently relapsing or steroid-dependent minimal change disease

Background

Studies comparing all treatment options for frequently-relapsing/steroid-dependent (FR/SD) minimal change disease (MCD) in adults are lacking.

Methods

Medical records of 76 adults with FR/SD MCD who were treated with corticosteroids as the first-line therapy were reviewed. Treatment options were compared for the time to relapse, change of therapy and progression (relapse on full-dose treatment).

Results

Second-line treatments included rituximab (RTX; n = 13), mycophenolate mofetil (MMF; n = 12), calcineurin inhibitors (CNI; n = 26) and cyclophosphamide (CTX; n = 16). During the second-line treatments, 48 (71.6%) patients relapsed at median 17 (range 2–100)  months. The majority of relapses occurred during dose tapering or off drug. Twenty of 65 (30.8%) changed therapy after the first relapse. The median time to relapse after the second line was 66 versus 28 months in RTX versus non-RTX groups (P = 0.170). The median time to change of treatment was 66 and 44 months, respectively (P = 0.060). Last-line treatment options included RTX (n = 8), MMF (n = 4), CNI (n = 3) and CTX (n = 2). Seven (41.2%) patients had a relapse during the last-line treatment at median 39 (range 5–112)  months. The median time to relapse was 48 versus 34 months in the RTX versus non-RTX groups (P = 0.727). One patient in the RTX group died presumably of heart failure. No major adverse event was observed. During the median follow-up of 81 (range 9–355)  months, no patients developed end-stage renal disease.

Conclusions

Relapse is frequent in MCD in adults. Patients treated with RTX may be less likely to require a change of therapy and more likely to come off immunosuppressive drugs.

A case of immune complex mediated tubulointerstitial disease and nephrotic syndrome: anti LRP-2 Nephropathy with diffuse podocyte effacement

Anti-LDL Receptor-Related Protein 2 (Anti-LRP2) nephropathy is a rare form of kidney disease that affects the older patients and is characterized with acute kidney injury (AKI) and progressive renal tubular injury associated with IgG immune complex deposits along the basement membrane of proximal tubules, and circulating autoantibodies to the proximal tubule brush border protein LRP2 (megalin). We present the case of a 79-year-old man who was hospitalized for worsening malaise, abdominal distention and bilateral lower extremity edema, diagnosed with AKI and had nephrotic range proteinuria. Percutaneous kidney biopsy revealed tubulointerstitial nephritis with IgG immune complex deposits along the basement membrane of proximal tubules and brush borders. Immunofluorescence staining for LRP2 (megalin) showed similar granular tubular basement membrane deposits along the proximal tubules and proximal tubule brush borders. Electron microscopy revealed global podocyte foot process effacement. The patient was started on oral prednisolone 1 mg/kg and rituximab at a dose of 375 mg/m² once weekly for 4 weeks with gradual tapering of prednisone. This case with AKI and nephrotic syndrome highlights the significant morphologic overlap with minimal change disease and anti-LRP2 nephropathy, which is associated with autoantibodies to the tubular brush border protein LRP2/megalin.

Acute Kidney Injury Associated with Minimal Change Nephrotic Syndrome in an Elderly Patient Successfully Treated with both Fluid Management and Specific Therapy Based on Kidney Biopsy Findings

Oliguric acute kidney injury (AKI) with minimal change nephrotic syndrome (MCNS) has long been recognized. Several mechanisms such as hypovolemia due to hypoalbuminemia and the nephrosarca hypothesis have been proposed. However, the precise mechanism by which MCNS causes AKI has not been fully elucidated. Herein, we describe an elderly patient with AKI caused by MCNS who fully recovered after aggressive volume withdrawal by hemodialysis and administration of a glucocorticoid. A 75-year-old woman presented with diarrhea and oliguria, and laboratory examination revealed nephrotic syndrome (NS) and severe azotemia. Fluid administration had no effect on renal dysfunction, and hemodialysis was initiated. Her renal function improved upon aggressive fluid removal through hemodialysis. Renal pathological findings revealed minimal change disease with faint mesangial deposits of IgA. After administration of methylprednisolone pulse therapy followed by oral prednisolone, she achieved complete remission from NS. The clinical course of this case supports the nephrosarca hypothesis regarding the mechanism of AKI caused by MCNS. Furthermore, appropriate fluid management and kidney biopsy are also important in elderly patients with AKI caused by NS.

[Kidney disease care for the elderly]

In our aging population, kidney disease management needs to take into account the frailty of the elderly. Standardized geriatric assessments can be proposed to help clinicians apprehend this dimension in their daily practice. These tools allow to better identify frail patients and offer them more personalized and harmless treatments. This article aims to focus on the kidney diseases commonly observed in elderly patients and analyze their specific nephrogeriatric care modalities. It should be noticed that all known kidney diseases can be also observed in the elderly, most often with a quite similar clinical presentation. This review is thus focused on the diseases most frequently and most specifically observed in elderly patients (except for monoclonal gammopathy associated nephropathies, out of the scope of this work), as well as the peculiarities of old age nephrological care.

Acute kidney injury in hospitalized patients who underwent percutaneous kidney biopsy for histological diagnosis of their renal disease

BACKGROUND

Performing a kidney biopsy is necessary to accurately diagnose diseases such as glomerulonephritis and tubulointerstitial nephritis, among other such conditions. These conditions predispose patients to chronic kidney disease, as well as acute kidney injury (AKI). Notably, most epidemiological studies describing AKI have not investigated this patient population.

METHODS

Included patients admitted to the nephrology ward of a tertiary hospital who underwent percutaneous kidney biopsy. AKI was diagnosed based on the Kidney Disease: Improving Global Outcomes criteria.

RESULTS

Of the 223 patients investigated, 140 (62.8%) showed AKI. Of these, 91 (65%), 19 (13.6%), and 30 (21.4%) presented with AKI classified as stages 1, 2, and 3, respectively. The primary indication for performing biopsy was nephrotic syndrome or nephrotic proteinuria (73 [52.1%] in the AKI vs. 51 [61.4%] in the non-AKI group, p = 0.048). Focal segmental glomerulosclerosis was the most prevalent primary disease (24 [17.1%] in the AKI vs. 15 [18.0%] in the non-AKI group, p = 0.150). Multivariate analysis of risk factors associated with AKI showed hemoglobin levels (odds ratio [OR] 0.805, 95% confidence interval [CI] 0.681-0.951, p = 0.011), serum high-density lipoprotein cholesterol levels (HDL-c, OR 0.970, 95% CI 0.949-0.992, p = 0.008), and baseline serum creatinine levels (OR 2.703, 95% CI 1.471-4.968, p = 0.001) were significantly associated with AKI.

CONCLUSIONS

We observed a high prevalence of AKI in hospitalized patients who underwent kidney biopsy to investigate their renal disease, particularly glomerulonephritis. Higher levels of hemoglobin and serum HDL-c were associated with a lower risk of AKI.

Verification of serum albumin elevating effect of cell-free and concentrated ascites reinfusion therapy for ascites patients: a retrospective controlled cohort study

Cell-free and concentrated ascites reinfusion therapy (CART) is frequently used to treat refractory ascites in Japan. However, its efficacy remains unclear. This controlled cohort study verified the serum albumin elevating effect of CART by comparisons with simple paracentesis. Ascites patients receiving CART (N = 88) or paracentesis (N = 108) at our hospital were assessed for the primary outcome of change in serum albumin level within 3 days before and after treatment. A significantly larger volume of ascites was drained in the CART group. The change in serum albumin level was +0.08 ± 0.25 g/dL in the CART group and −0.10 ± 0.30 g/dL in the paracentesis group (P < 0.001). The CART – paracentesis difference was +0.26 g/dL (95%CI +0.18 to +0.33, P < 0.001) after adjusting for potential confounders by multivariate analysis. The adjusted difference increased with drainage volume. In the CART group, serum total protein, dietary intake, and urine volume were significantly increased, while hemoglobin and body weight was significantly decreased, versus paracentesis. More frequent adverse events, particularly fever, were recorded for CART, although the period until re-drainage was significantly longer. This study is the first demonstrating that CART can significantly increase serum albumin level as compared with simple paracentesis. CART represents a useful strategy to manage patients requiring ascites drainage.

Pathogenesis and Management of Acute Kidney Injury in Patients with Nephrotic Syndrome Due to Primary Glomerulopathies

Acute kidney injury in the context of nephrotic syndrome is a serious and alarming clinical problem. Largely, acute kidney injury is a relatively frequent complication among patients with comorbidities while it has been independently associated with an increased risk of adverse outcomes, including death and chronic kidney disease. Nephrotic syndrome, without hematuria or with minimal hematuria, includes a list of certain glomerulopathies; minimal change disease, focal segmental glomerulosclerosis and membranous nephropathy. In the light of primary nephrotic syndrome, pathophysiology of acute kidney injury is differentiated by the nature of the primary disease and the severity of the nephrotic state. This review aims to explore the clinical circumstances and pathogenetic mechanisms of acute kidney injury in patients with nephrotic syndrome due to primary glomerulopathies, focusing on newer perceptions regarding the pathogenesis and management of this complicated condition, for the prompt recognition and timely initiation of appropriate treatment in order to restore renal function to its baseline level. Prompt recognition of the precise cause of acute kidney injury is crucial for renal recovery. Clinical characteristics, laboratory and serological findings along with histopathological findings, if required, will reveal the implicated pathway leading to individualized approach and management.

Clinical features and outcomes of kidney transplant recipients with focal segmental glomerulosclerosis recurrence

AIM

Focal segmental glomerulosclerosis recurs in up to 30% and up to 80% of adult and pediatric kidney transplant recipients, respectively. There is no standard of care treatment. The purpose of this study was to evaluate clinical characteristics, treatments and outcomes of patients with focal segmental glomerulosclerosis recurrence (FSGSr).

METHODS

This was a retrospective single-center cohort study including FSGSr patients treated with plasmapheresis (PP) and combinations of high dose steroids, cyclosporine and rituximab.

RESULTS

Among 61 patients included in this analysis the median time to diagnosis was 19 days. The incidence of first biopsy-confirmed FSGSr was 18% reaching 52.4% with follow-up biopsies. During PP treatment 54% of the patients developed infectious complications. PP was discontinued in 37% of patients due to treatment failure (no remission or graft loss) and in 26% due to an adverse event. All patients who discontinued PP due to adverse event did not show clinical response or lost the allograft. The incidence of acute rejection was 34.4%. The incidences of partial and complete remissions were 16.4% and 27.8%, respectively. Overall 6-years patient and graft survivals were 90.7% and 64.5%, respectively.

CONCLUSION

This analysis confirms the low, variable and unpredictable rate of FSGSr remission, inconsistencies among available therapeutic options and its high rate of adverse events, and the negative impact on graft survival.

Evaluation of kidney biopsies in elderly patients

OBJECTIVE

The renal parenchymal disease spectrum in geriatric patients is similar to that in younger patients and can be controlled by appropriate treatment. We evaluated the clinicopathological features of kidney biopsies from geriatric patients.

MATERIALS AND METHODS

One hundred nine native kidney biopsies from older patients (> 65 years old) obtained from 2005 to 2014 were evaluated retrospectively. The specimens were inspected by the same pathologist in the same laboratory by light microscopy and immunofluorescence.

RESULTS

The mean age of the patients was 72.4 ± 7.8 years (range 65-90 years), and 51.3% were female. The most frequent indication for kidney biopsy was proteinuria at the nephrotic level (56.8%). The most frequent histopathological diagnoses were focal segmental glomerulosclerosis in primary glomerulonephritis and secondary amyloidosis in secondary glomerulonephritis. The rate of major complications due to kidney biopsy was < 1%.

RESULT

Kidney biopsy is an effective and safe method of evaluating renal parenchymal diseases in older patients.

Acute kidney injury in childhood-onset nephrotic syndrome: Incidence and risk factors in hospitalized patients

Background

Nephrotic syndrome (NS) is the most common glomerulopathy in children. Acute kidney injury (AKI) is a common complication of NS, caused by severe intravascular volume depletion, acute tubular necrosis, interstitial nephritis, or progression of NS. However, the incidence and risk factors of childhood-onset NS in Korea are unclear. Therefore, we studied the incidence, causes, and risk factors of AKI in hospitalized Korean patients with childhood-onset NS.

Methods

We conducted a retrospective review of patients with childhood-onset NS who were admitted to our center from January 2015 to July 2017. Patients with decreased renal function or hereditary/secondary NS, as well as those admitted for management of other conditions unrelated to NS, were excluded.

Results

During the study period, 65 patients with idiopathic, childhood-onset NS were hospitalized 90 times for management of NS or its complications. Of these 90 cases, 29 met the Kidney Disease Improving Global Outcomes criteria for AKI (32.2%). They developed AKI in association with infection (n = 12), NS aggravation (n = 11), dehydration (n = 3), and intravenous methylprednisolone administration (n = 3). Age ≥ 9 years at admission and combined use of cyclosporine and renin-angiotensin system inhibitors were risk factors for AKI.

Conclusion

AKI occurred in one-third of the total hospitalizations related to childhood-onset NS, owing to infection, aggravation of NS, dehydration, and possibly high-dose methylprednisolone treatment. Age at admission and use of nephrotoxic agents were associated with AKI. As the AKI incidence is high, AKI should be considered during management of high-risk patients.

Acute kidney injury complicating nephrotic syndrome of minimal change disease

Minimal change disease accounts for 70% to 90% of cases of nephrotic syndrome in children. It also causes nephrotic syndrome in adults, including patients older than age 60. Renal function is altered moderately in approximately 20% to 30% of patients because foot-process fusion impairs filtration of water and solutes. The glomerular filtration rate is reduced by approximately 20% to 30% and returns to baseline with remission of proteinuria. Over the past 50 years, a number of publications have reported cases of acute kidney injury occurring in approximately one-fifth to one-third of adult cases in the absence of prior or concomitant renal disease. Clinical attributes point to a male predominance, age >50, massive proteinuria, severe hypoalbuminemia, a background of hypertension and vascular lesions on kidney biopsy, along with ischemic tubular necrosis. Acute kidney injury may require dialysis for weeks or months until remission of proteinuria allows resolution of oliguria. In some cases, renal function does not recover. An effect of endothelin-1-induced vasoconstriction at the onset of proteinuria has been proposed to explain tubular cell ischemic necrosis. The main factors causing acute kidney injury in patients with minimal change disease are diuretic-induced hypovolemia and nephrotoxic agents. Acute kidney injury is uncommon in children in the absence of intercurrent complications. Infection, nephrotoxic medication, and steroid resistance represent the main risk factors. In all patients, the goal of supportive therapy is essentially to buy time until glucocorticoids obtain remission of proteinuria, which allows resolution of renal failure.

Minimal change disease related to rifampicin presenting with acute renal failure during treatment for latent tuberculosis infection: A case report

RATIONALE

The standard drugs used to treat tuberculosis are rifampicin and isoniazid. These agents are usually safe and inexpensive for short-term use in treatment of latent tuberculosis infection, but sometimes cause adverse renal effects, including minimal change disease (MCD).

PATIENT CONCERNS

Here, we report a 51-year-old woman with latent tuberculosis infection who developed nephrotic syndrome during treatment with rifampicin and isoniazid for 25 days.

DIAGNOSES

Renal biopsy findings were compatible with MCD, and she had no relevant medical history and was not taking other medications. A diagnosis of anti-tuberculosis drug- induced MCD was made. This is the first report of acute renal failure due to rifampicin and/or isoniazid-induced MCD.

INTERVENTIONS

After cessation of rifampicin and isoniazid, however, acute renal failure progressed and she was treated with temporary dialysis and oral prednisolone.

OUTCOMES

The patient achieved complete remission after cessation of rifampicin and isoniazid with steroid therapy.

LESSONS

This case demonstrates that rifampicin and/or isoniazid can cause nephrotic syndrome with acute renal failure during the first months of continuous latent tuberculosis therapy. Therefore, renal function and proteinuria should be monitored carefully in all patients taking rifampicin and isoniazid, especially during the first few months of therapy.

Acute Kidney Injury in Nephrotic Syndrome

Nephrotic syndrome (NS) is one of the commonest kidney diseases seen in childhood and is characterized by a relapsing remitting course. Various complications have been reported in children with NS, including infections, thromboembolism, hypovolemia, and acute kidney injury (AKI). There is often a modest decrease in renal function in patients with active proteinuria due to decreased glomerular permeability that improves when they go into remission. However, more pronounced AKI in NS is multifactorial in origin. It is most often secondary to hypovolemia, nephrotoxic medications, and infections, although other reasons may also be seen. Recent years have seen an increase in the incidence of AKI in NS. There is limited data on the correlation between AKI in pediatric NS and long-term outcomes. A better understanding of this increasingly common condition will help improve patient outcomes.

Unique proximal tubular cell injury and the development of acute kidney injury in adult patients with minimal change nephrotic syndrome

Background

Adult patients with minimal change nephrotic syndrome (MCNS) are often associated with acute kidney injury (AKI). To assess the mechanisms of AKI, we examined whether tubular cell injuries unique to MCNS patients exist.

Methods

We performed a retrospective analysis of clinical data and tubular cell changes using the immunohistochemical expression of vimentin as a marker of tubular injury and dedifferentiation at kidney biopsy in 37 adult MCNS patients. AKI was defined by the criteria of the Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guidelines for AKI.

Results

Thirteen patients (35.1%) were designated with AKI at kidney biopsy. No significant differences in age, history of hypertension, chronic kidney disease, diuretics use, proteinuria, and serum albumin were noted between the AKI and non-AKI groups. Urinary N-acetyl-β-D-glucosaminidase (uNAG) and urinary alpha1-microglobulin (uA1MG) as markers of tubular injury were increased in both groups, but the levels were significantly increased in the AKI group compared with the non-AKI group. The incidence of vimentin-positive tubules was comparable between AKI (84.6%) and non-AKI (58.3%) groups, but vimentin-positive tubular area per interstitial area was significantly increased in the AKI group (19.8%) compared with the non-AKI group (6.8%) (p = 0.011). Vimentin-positive injured tubules with tubular simplification (loss of brush-border of the proximal tubule/dilated tubule with flattening of tubular epithelium) were observed in the vicinity of glomeruli in both groups, suggesting that the proximal convoluted tubules were specifically injured. Two patients exhibited relatively severe tubular injuries with vimentin positivity and required dialysis within 2 weeks after kidney biopsy. The percentage of the vimentin-positive tubular area was positively correlated with uNAG but not with uA1MG in the non-AKI group.

Conclusions

Proximal tubular injuries with increased uNAG exist in MCNS patients without renal dysfunction and were more severe in the AKI group than they were in the non-AKI group. The unique tubular injuries probably due to massive proteinuria might be a predisposing factor for the development of severe AKI in adult MCNS patients.

The level of urinary semaphorin3A is associated with disease activity in patients with minimal change nephrotic syndrome

Semaphorin3A is a secreted protein known to be involved in organogenesis, immune responses and cancer. In the kidney, semaphorin3A is expressed in the glomerular podocytes, distal tubules and collecting tubules, and believed to play a role in the regulation of the kidney development and function. We examined the serum and urinary semaphorin3A levels in 72 patients with renal disease and 5 healthy volunteers. The patients had been diagnosed with thin basement membrane disease (n=4), minimal change nephrotic syndrome (MCNS; n=22), IgA nephritis (n=21), membranous nephropathy (n=16) and focal segmental glomerular sclerosis (n=9). The level of urinary semaphorin3A in MCNS patients tended to be relatively high among all disease groups. We also investigated the urinary semaphorin3A level in 7 patients with MCNS from disease onset to remission during the drug therapy. MCNS patients in pre-remission states had higher urinary semaphorin3A levels than those in post-remission states receiving immunosuppressive therapies. These results suggested that the urinary semaphorin3A level correlates with the MCNS activity. Semaphorin3A has the potential as a biomarker for MCNS to clarify the reactivity for therapy and may be useful in examining other glomerular diseases with proteinuria as well.

Single low-dose rituximab for the treatment of steroid-resistant nephrotic syndrome with acute kidney injury

The efficacy of rituximab for kidney disease, such as frequent relapsing nephrotic syndrome, has been reported recently. Herein, we report a case of a patient with acute kidney injury that was steroid-resistant nephrotic syndrome who responded to a single administration of low-dose rituximab. An 86-year-old Japanese woman with hypertension presented with severe peripheral edema within several days after onset. Due to the patient's age, renal biopsy was not performed, nephrotic syndrome was diagnosed and prednisolone was administered at 40 mg/day on the day after admission. However, anuria developed and hemodialysis was inevitably initiated on the 5th hospital day. The renal function did not recover, and the general condition gradually became aggravated. On the 50th hospital day, 100 mg rituximab was administered, which led to immediate depletion of CD20-positive cells. The urine volume gradually increased from 2-3 weeks after the rituximab administration, and the renal function recovered slightly. After 5 weeks, it became possible to wean the patient from dialysis, which had been applied for 3 months. Rituximab might be an option for the treatment of acute kidney injury due to steroid-resistant nephrotic syndrome.

Acute kidney injury in idiopathic nephrotic syndrome of childhood is a major risk factor for the development of chronic kidney disease

Background: Acute kidney injury (AKI) is an important complication of idiopathic nephrotic syndrome (INS) and is associated with adverse outcomes, especially the development of chronic kidney disease (CKD). We aimed to determine the clinical profile of children with INS who developed AKI and its short-term outcome.

Material and methods: This prospective study was conducted from March 2014 to October 2015. A total of 119 children of INS (age: 2–18 years) fulfilling the pediatric RIFLE criteria for the diagnosis of AKI were enrolled and followed up for 3 months to determine the outcome. Factors predisposing to CKD were studied.

Results: The mean age at presentation was 8.8 ± 3.59 years and males were 74 (62.2%). At presentation, 61 (51.3%) children were in Risk category, 43 (36.1%) in Injury category, and 15 (12.6%) in Failure category. Most of them (41.2%) had steroid-resistant nephrotic syndrome (SRNS) and focal segmental glomerulosclerosis (FSGS) on histopathology (33.6%).

Infections were the major predisposing factor for AKI in 67 (56.3%) cases. Drug toxicity was the next common, found in 52 (43.7%) children. A total of 65 (54.6%) children recovered from AKI, while 54 (45.4%) did not. CKD developed in 49 (41.2%) non-recovered cases and 5 (4.2%) children succumbed to acute illness. SRNS, cyclosporine use, FSGS on histology, and drug toxicity were significant factors associated with the development of CKD.

Conclusion: AKI associated with INS is a reversible condition in most cases but it can progress to CKD, especially among those who have SRNS, FSGS, and drug toxicity.

Influence of acute kidney injury on the time to complete remission in adult minimal change nephrotic syndrome: a single-centre study

AIM

Acute kidney injury (AKI) is a common complication of minimal change nephrotic syndrome (MCNS), particularly in adults. We evaluated the prevalence of AKI at the onset of adult MCNS and analyzed the influence of AKI on the duration of achieving complete remission (CR).

METHODS

A retrospective, single-centre, dynamic cohort study was conducted with biopsy-proven, first-onset, adult MCNS patients treated with corticosteroids. Fifty-three consecutive patients diagnosed with MCNS from January 2000 to April 2014 were enrolled. Age, gender, daily urinary protein excretion, and serum creatinine levels were measured. To evaluate AKI during induction, we used the Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guidelines for AKI and judged AKI stage according to the fluctuations in serum creatinine levels during the first 4 weeks of starting corticosteroid therapy.

RESULTS

Twenty patients (37.7%) met the AKI criteria and all 53 patients achieved CR within 1 year. Kaplan-Meier analysis showed that the median time to CR was significantly longer in patients with AKI than in patients without AKI. Cox proportional hazard analysis showed that the hazard ratio (HR) associated with the presence of AKI for achieving CR within 4 weeks was 0.36 after adjustment for age, gender, serum albumin, daily urinary protein excretion, hypertension, administration of 25% albumin, and methylprednisolone pulse therapy. A graded association was also observed between AKI stage and HR for achieving CR.

CONCLUSIONS

The prevalence of AKI is high in adult patients with MCNS during induction therapy. AKI is an independent factor that delays the time to CR.

The Clinical Course of Minimal Change Nephrotic Syndrome With Onset in Adulthood or Late Adolescence: A Case Series

BACKGROUND

Few studies have examined the treatment and outcome of adult-onset minimal change nephrotic syndrome (MCNS). We retrospectively studied 125 patients who had MCNS with onset in either adulthood or late adolescence. Presenting characteristics, duration of initial treatment and response to treatment, relapse patterns, complications, and long-term outcome were studied.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

Patients with new-onset nephrotic syndrome 16 years or older and a histologic diagnosis of MCNS in 1985 to 2011 were identified from pathology records of 10 participating centers.

OUTCOMES

Partial and complete remission, treatment resistance, relapse, complications, renal survival.

RESULTS

Corticosteroids were given as initial treatment in 105 (84%) patients. After 16 weeks of corticosteroid treatment, 92 (88%) of these patients had reached remission. Median time to remission was 4 (IQR, 2-7) weeks. 7 (6%) patients initially received cyclophosphamide with or without corticosteroids, and all attained remission after a median of 4 (IQR, 3-11) weeks. 13 (10%) patients reached remission without immunosuppressive treatment. One or more relapses were observed in 57 (54%) patients who received initial corticosteroid treatment. Second-line cyclophosphamide resulted in stable remission in 57% of patients with relapsing MCNS. Acute kidney injury was observed in 50 (40%) patients. Recovery of kidney function occurred almost without exception. Arterial or venous thrombosis occurred in 11 (9%) patients. At the last follow-up, 113 (90%) patients were in remission and had preserved kidney function. 3 patients with steroid-resistant MCNS progressed to end-stage renal disease, which was associated with focal segmental glomerulosclerosis lesions on repeat biopsy.

LIMITATIONS

Retrospective design, variable treatment protocols.

CONCLUSIONS

The large majority of patients who had MCNS with onset in adulthood or late adolescence were treated with corticosteroids and reached remission, but many had relapses. Cyclophosphamide resulted in stable remission in many patients with relapses. Significant morbidity was observed due to acute kidney injury and other complications. Progression to end-stage renal disease occurred in a few patients and was explained by focal segmental glomerulosclerosis.

Adult Nephrotic Syndrome after Hematopoietic Stem Cell Transplantation: Renal Pathology is the Best Predictor of Response to Therapy

Nephrotic syndrome (NS) after allogeneic hematopoietic stem cell transplantation (HSCT) is a rare phenomenon usually associated with graft-versus-host disease (GVHD). This systematic review of post-HSCT NS cases reported in the literature aimed to identify risk factors and unique features of the disease in this clinical setting. One hundred sixteen cases of post-HSCT NS published in the English literature between 1988 and 2015 were revealed and analyzed. The median onset of NS was 20.5 months (range, 3 to 174) post-HSCT. NS development was associated with acute or chronic GVHD in 87.2% of cases. Membranous nephropathy (MGN) was the most frequent pathology (65.5%), followed by minimal change disease (MCD) (19%). Complete remission of the NS was achieved in 63.5% of patients (59.1% of MGN cases and 81.3% of MCD cases; P = .15). Patients presenting with MCD recovered at a median of 1.75 months (range, 1 to 12) and with MGN a median of 7 months (range, 1 to 53) (P = .001). NS was treated with corticosteroids alone in 16.8% of patients and with a combination of corticosteroids and other immunosuppressive agents in 73.5% of patients. Univariate analysis failed to identify a single predictive factor of response to therapy. In conclusion, post-HSCT NS usually develops concomitant to GVHD and is associated with high rates of response to therapy. Although most patients were treated with a combination of immunosuppressive drugs, single-agent therapy with steroids may be sufficient in some cases.

Primary glomerular diseases in the elderly

Primary glomerular diseases in the elderly population are a frustrating topic due to difficulties in both the diagnosis and decision making about treatment. The most frequent type of primary glomerular disease in elderly is membranous nephropathy; while its counterpart in younger population is IgA nephropathy. The most frequent cause of nephrotic syndrome in the elderly is also membranous nephropathy. Pauci-immune crescentic glomerulonephritis (GN) rate increases both in elderly and very elderly population. Pauci-immune crescentic GNs should be regarded as urgencies in elderly patients as in their younger counterparts due to potential for causing end-stage renal disease in case of delayed diagnosis and treatment, and also causing mortality due to alveolar hemorrhage in patients with pulmonary involvement. Renal biopsy is the inevitable diagnostic method in the elderly as in all other age groups. Renal biopsy prevents unnecessary treatments and provides prognostic data. So advanced age should not be the sole contraindication for renal biopsy. The course of primary glomerular diseases may differ in the elderly population. Acute kidney injury is more frequent in the course and renal functions may be worse at presentation. These patients are more prone to be hypertensive. The decision about adding immune suppressive therapies to conservative methods should be made considering many factors like co-morbidities, drug side effects and potential drug interactions, risk of infection, patient preference, life expectancy and renal functions at the time of diagnosis.

The spectrum of biopsy-proven kidney diseases in elderly Chinese patients

BACKGROUND

Studies on biopsy-proven renal disease in the elderly (age ≥65 years) are extremely limited in China. The aim of this study was to examine the spectrum of renal diseases and their clinical presentations in elderly patients undergoing renal biopsy.

METHODS

All native renal biopsies (n = 851) performed in patients aged ≥65 years from January 2003 to December 2012 were retrospectively analyzed. The results were compared with a control group of 28 574 patients aged 18-64 years undergoing renal biopsy over the same period.

RESULTS

These 851 patients included 549 males and 302 females. Primary glomerular diseases (53.94%) occurred more frequently than secondary glomerular diseases (36.49%). The clinical manifestations were nephrotic syndrome (NS) in 29.49% of the patients, chronic renal failure in 24.68%, proteinuria and hematuria in 13.28%, proteinuria in 10.93%, acute kidney injury (AKI) in 10.81% and AKI and NS in 8.93%. Membranous nephropathy (MN) was the most frequent diagnosis (28.79%), followed by diabetic nephropathy (DN, 9.75%), IgA nephropathy (IgAN, 9.64%) and vasculitis (6.82%). When compared with the control group, the results showed that MN (P < 0.0001), DN (P < 0.0001), vasculitis (P < 0.0001) and amyloidosis (P < 0.0001) occurred more frequently and IgAN (P < 0.0001), lupus nephritis (P < 0.0001) and minimal change disease (P < 0.0001) occurred less frequently in the elderly.

CONCLUSION

This study is the first and largest renal biopsy series to analyze patients aged ≥65 years in China, and the results obtained from this study may increase the knowledge of renal diseases in elderly patients.

Pathological patterns of primary nephrotic syndrome in Central China: a retrospective study of 627 cases

BACKGROUND

The pathological patterns underlying PNS in adult are poorly studied in Central China.

METHODS

This is a retrospective analysis of the clinical and pathologic data involving 627 adult patients with PNS who have been finished the renal biopsies from January 2009 to September 2012 in XiangYa 2nd Hospital of Central South University. Patients enrolled in our study were all from Central China.

RESULTS

There were 379 males and 248 females, formed the ratio of 1.53:1. There existed three main sorts of pathological patterns underlying PNS: membranous nephropathy (MN) 26.63%, minimal change disease (MCD) 23.60%, IgA nephropathy (IgAN) 23.39%. Among all biopsies, the proportion of FSGS underlying PNS increased from 5.8% during the period from 2009 to 2010 to 14.7% during the period from 2011 to 2012. The most common complication of PNS was infectious diseases, and MCD underlying PNS ran a higher risk of encountering acute renal injury. IgAN had the highest incidence of hematuresis. The common pathological patterns of PNS differed in age-brackets: IgAN and MCD were the main pathological lesions in patients aged from 16 to 30 years; MN mostly occurs in patients over 30. MCD was the dominating pathological lesions underlying IgAN which expressed as PNS.

CONCLUSIONS

(1) MN was the most frequent pathological pattern underlying PNS, the proportion of FSGS underlying PNS increased during the last 2 years. (2) The common pathological patterns of PNS differed in age-brackets and pathological patterns correlated to the complications or comorbidities of PNS to some extent.

Increasing frequency of acute kidney injury amongst children hospitalized with nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) is among the most common kidney diseases seen in children. The major complications of NS include infection, acute kidney injury (AKI), and thromboembolism (TE). The objective of this study was to analyze long-term trends in the epidemiology of major complications of pediatric NS.

METHODS

We used the Healthcare Cost and Utilization Project Kids' Inpatient Database for the years 2000-2009 to perform an analysis of U.S. hospitalizations of children diagnosed with NS with or without infection, AKI or TE.

RESULTS

The frequency of NS hospitalizations complicated by AKI increased by 158 % between 2000 and 2009 (p < 0.001). The frequency of NS hospitalizations with infection and TE remained stable overall. Pneumonia was the most common infectious complication while peritonitis decreased by 50 % (p < 0.001). Importantly, development of any of these major complications of NS resulted in ∼2-3-fold increases in both hospital charges and length of stay.

CONCLUSIONS

It is concerning that the frequency of AKI in children hospitalized with NS has more than doubled in the past decade. Strategies to prevent or initiate earlier treatments for complications of NS could have a major impact on both morbidity and health care expenses.

Acute kidney injury in a patient with membranous nephropathy - a case report

Acute Kidney Injury (AKI) is one of the most challenging problems faced by clinicians in the tropics owing to its fast-changing burden. Acute Kidney Injury is an important complication of membranous nephropathy. Causes are varied and include hypovolumia, crescentic conversion of preexisting nephropathy, renal vein thrombosis, NSAID'S, vasculitis, and sepsis. In this case report we discuss the case of membranous nephropathy in a young adult complicated by AKI. This report highlights the importance of early renal biopsy in patients with post GE AKI not improving on hemodialysis. Here we also discuss the potential differentials to be considered in a case of membranous nephropathy with AKI.

Serial Tc-99m MAG3 renography evaluating the recovery of acute kidney injury associated with minimal change nephrotic syndrome

Acute kidney injury (AKI) is a well-recognized complication of minimal change nephrotic syndrome (MCNS). Previous reports support the concept that AKI associated with MCNS is reversible; however, information regarding the hemodynamic basis of AKI in MCNS is insufficient. We herein describe a case of AKI in a man with MCNS. In this case, monitoring the longitudinal changes in renal perfusion using serial Tc-99m-MAG3 renal scanning was beneficial for evaluating the pathophysiological background associated with the development of AKI. The potential impact of serial renal scanning in MCNS patients with AKI will also be discussed.

Acute tubular necrosis and renal failure in patients with glomerular disease

Renal failure is common in patients with glomerular disease. Although renal failure may result from the glomerular lesion itself, it is also observed in patients with minimal glomerular alterations. Degenerative changes and necrosis of the tubular epithelium are common findings in kidney biopsies from these patients. The aim of this work is to examine the association between acute tubular necrosis (ATN) and renal failure in patients with glomerulopathy and to estimate the relationship between the degree of ATN and renal failure in these patients. Data on age, sex, presence of nephrotic syndrome, and renal failure were recorded for 149 patients, who underwent a renal biopsy for the diagnosis of glomerulopathy. The biopsies were reviewed, and ATN, when present, was classified as one of four grades depending on its intensity. The mean age of the patients was 21 ± 16 years. Eighty patients (54%) were male, 43 (42%) had renal failure, 104 (72%) had nephrotic syndrome, and 66 (45%) had minimal change disease or focal segmental glomerulosclerosis. ATN was present in 115 (77%) patients. The frequency of renal failure was directly correlated with the intensity of ATN [odds ratio (OR) of 26.0 for patients with grade 2 lesions and OR of 45.5 for patients with grade 3 lesions]. ATN is a common finding in the biopsies of patients with glomerulopathy. The severity of ATN is directly associated with the frequency of renal failure in these patients.

Acute kidney injury in adult idiopathic nephrotic syndrome

OBJECTIVE

This study aims to investigate the epidemiology, clinical and histological features, and prognosis of acute kidney injury (AKI) according to RIFLE classification in adult patients with idiopathic nephrotic syndrome.

METHODS

In this retrospective study, 277 patients with idiopathic nephrotic syndrome were reviewed from June 2005 to June 2009.

RESULTS

Fifty-one (18%) patients entered RIFLE class Risk (AKI-R); 24 (9%) patients entered RIFLE class Injury (AKI-I); and 20 (7%) patients entered RIFLE class Failure (AKI-F). Logistic regression analysis showed that severe hypoalbuminemia, increase in age, and being male were risk factors of AKI. Cumulative recovery rates in 3 months for groups AKI-R, AKI-I, and AKI-F were 95%, 100%, and 94%, respectively (p  =  0.21). The mean time to recovery for groups AKI-R, AKI-I, and AKI-F was 20 ± 3, 25 ± 4, and 30 ± 5 days, respectively. Cumulative complete remission rates in 3 months for groups AKI-R, AKI-I, and AKI-F were 92%, 86%, and 65%, respectively (p  =  0.002). The mean time to remission for groups AKI-R, AKI-I, and AKI-F was 28 ± 3, 39 ± 6, and 62 ± 8 days, respectively.

CONCLUSION

AKI is not uncommon in adult idiopathic nephrotic syndrome. More severe AKI was associated with longer time of nephrotic syndrome complete remission. Renal function can recover completely in most of the patients.

Challenges in clinical-pathologic correlations: acute tubular necrosis in a patient with collapsing focal and segmental glomerulosclerosis mimicking rapidly progressive glomerulonephritis

Herein, we report a case of acute kidney injury (AKI) due to diarrhea-induced acute tubular necrosis (ATN) in a patient with nephrotic syndrome secondary to biopsy-proven collapsing focal and segmental glomerulosclerosis (FSGS). The clinical picture mimicked rapidly progressive glomerulonephritis (RPGN) and motivated pulse therapy with methylprednisolone and cyclophosphamide. The case presentation is followed by a brief overview of the epidemiology of AKI in nephrotic syndrome as well as a discussion of its risk factors and potential mechanisms involved.

The spectrum of kidney involvement in lymphoma: a case report and review of the literature

Kidney involvement is an under-recognized complication of both Hodgkin and non-Hodgkin lymphoma. The diversity of lymphoma-related renal manifestations makes diagnosis difficult. Although abrupt worsening of kidney function may be the first sign of malignant disease, renal effects can be subtle or even silent. The causes of renal involvement similarly are varied. We discuss a case of non-Hodgkin lymphoma and associated kidney failure from several distinct malignancy-related mechanisms and review the spectrum of lymphoma-related kidney involvement.

Minimal mesangial lupus nephritis: a systematic review

OBJECTIVES

To summarize the clinical presentation, histological features, treatment, and outcome of minimal change nephropathy (MCN) in patients with systemic lupus erythematosus (SLE).

METHODS

We performed a systematic review of cases of MCN in SLE patients reported in the English literature from January 1985 to May 2009 by a Medline search.

RESULTS

The estimated prevalence of MCN in biopsy-proven lupus nephritis is 2.3% in childhood and 1.1% in adults. There are 13 individual cases (12 women, one man) of SLE-related MCN reported in the literature. The mean age of nephritis onset was 32.7 years. In six (46%) patients, MCN was the initial manifestation of SLE. All patients presented with nephrotic syndrome and two (15%) had active urinary sediments. Renal function was impaired in eight (62%) patients and six (46%) patients had active lupus serology. All patients responded promptly to high-dose glucocorticoids but four (31%) had relapse of proteinuria during their course of SLE. None of the patients developed thromboembolic or infective complications.

CONCLUSIONS

MCN is an uncommon histological class of lupus nephritis. Typically, patients present with heavy proteinuria, and transient renal dysfunction is common. The prognosis of MCN in SLE appears to be good because of its rapid response to glucocorticoids. Relapses of proteinuria may be reduced by the use of maintenance immunosuppression. Alkylating agents, calcineurin inhibitors, mycophenolate mofetil, and rituximab can be considered in glucocorticoid-dependent or refractory cases of SLE-related MCN.

Misapplications of commonly used kidney equations: renal physiology in practice

Equations for estimating GFR, quantifying urinary protein excretion, and assessing renal sodium handling are widely used in routine nephrology and general medical and surgical practice. If these equations are applied in circumstances inconsistent with the clinical situations for or extrapolated beyond the limits in which they were validated, clinicians can come to erroneous conclusions, which could be detrimental for patient care. This review uses clinical vignettes to demonstrate some of the common pitfalls that clinicians may encounter in the use of these equations and considers the physiologic principles underlying their use. Equations for assessing aspects of renal function should only be used in specific clinical situations, if the underlying assumptions regarding their calculations and values are satisfied.

Adult minimal-change disease: clinical characteristics, treatment, and outcomes

Minimal-change disease (MCD) counts for 10 to 15% of cases of primary nephrotic syndrome in adults. Few series have examined this disease in adults. A retrospective review was performed of 95 adults who had MCD and were seen at a single referral center. Examined were presenting features, response to daily versus alternate-day steroids, response to second-line agents, relapse patterns, complications of the disease and therapy, presence of acute renal failure (ARF), and outcome data. Sixty-five patients received daily and 23 received alternate-day steroids initially. There were no differences in remissions, time to remission, relapse rate, or time to relapse between daily- and alternate-day-treated patients. More than one quarter of patients were steroid resistant. At least one relapse occurred in 73% of patients; 28% were frequently relapsing. A significant proportion of frequently relapsing patients became steroid dependent. Second-line agents were used for steroid dependence, steroid resistance, or frequent relapses. No single agent proved superior. There were more remissions with second-line agents in steroid-dependent patients compared with steroid-resistant patients, and remissions were more likely to be complete in steroid-dependent patients. ARF occurred in 24 patients; they tended to be older and hypertensive with lower serum albumin and more proteinuria than those without ARF. At follow up, patients with an episode of ARF had higher serum creatinine than those without ARF. Four patients progressed to ESRD. These patients were less likely to have responded to steroids and more likely to have FSGS on repeat renal biopsy. In this referral MCD population, response to daily and alternate-day steroids is similar. Second-line agents give greater response in patients who are steroid dependent. ARF occurs in a significant number of adult MCD patients and may leave residual renal dysfunction. Few patients progress to ESRD.

Minimal change disease with acute renal failure: a case against the nephrosarca hypothesis

An unusual but well-documented presentation of minimal change disease is nephrotic proteinuria and acute renal failure. One pathophysiological mechanism proposed to explain this syndrome is nephrosarca, or severe oedema of the kidney. We describe a patient with minimal change disease who presented with heavy proteinuria and acute renal failure but had no evidence of renal interstitial oedema on biopsy. Aggressive fluid removal did not reverse the acute renal failure. Renal function slowly returned concomitant with resolution of the nephrotic syndrome following corticosteroid therapy. The time profile of the clinical events is not compatible with the nephrosarca hypothesis and suggests an alternative pathophysiological model for the diminished glomerular filtration rate seen in some cases of minimal change disease.

ARF in children with minimal change nephrotic syndrome may be related to functional changes of the glomerular basal membrane

BACKGROUND

Acute renal failure (ARF) is a rare complication in children with minimal change nephrotic syndrome (MCNS). Several etiologic factors (renal vein thrombosis, side effect of such drugs as nonsteroidal anti-inflammatory drugs, and infections) have been described, but often such conditions are lacking, and hemodynamic derangements or changes in glomerular permeability are suspected.

METHODS

We assessed the role of alterations in renal perfusion and glomerular permeability by measuring clearances of inulin and para-aminohippurate before and during intravenous administration of a 20% albumin solution in patients with MCNS and oliguric ARF (serum creatinine > 1 mg/dL [88 micromol/L], urine output < 0.5 mL/kg body weight/h).

RESULTS

Eleven patients aged 2.5 to 15 years with biopsy-proven MCNS were studied. Before albumin administration, all patients had a significantly decreased glomerular filtration rate (GFR), whereas most renal plasma flow (RPF) values were within the normal range. This resulted in a significantly decreased filtration fraction (FF; GFR/RPF x 100), which was extremely low (<7%) in 4 patients. There was a heterogeneous response to albumin administration. Albumin infusion tended to increase RPF, but changes did not reach statistical significance. Some patients showed an increase in glomerular filtration, whereas in others, it decreased. In 7 patients, FF remained unchanged or decreased even further.

CONCLUSION

Our data suggest that, although in some patients decreased intravascular volume may contribute to reduced renal function, changes in glomerular permeability may have a major role in ARF occurring in uncomplicated MCNS.

Acute renal failure in children with idiopathic nephrotic syndrome

Acute renal failure (ARF) is an uncommon but alarming complication of idiopathic nephrotic syndrome. The renal failure could be secondary to causes evident from the history and evaluation, such as severe intravascular volume depletion, acute tubular necrosis, allergic interstitial nephritis, bilateral renal vein thrombosis, acute pyelonephritis, or rapid progression of the original glomerular disease. It may be termed idiopathic if the underlying cause is undetermined. We present three children with idiopathic nephrotic syndrome who were admitted with acute renal failure. One case was due to drug-induced allergic interstitial nephritis. The other two were idiopathic in nature. Improvement in renal function occurred in the three patients over a variable period of 10 days to 4 weeks. After careful exclusion of well-known causes of acute renal failure, idiopathic acute renal failure (IARF) should be considered as a diagnostic possibility in these patients. The exact pathophysiology of IARF is not understood. Possible proposed explanations include interstitial edema, tubular obstruction, altered glomerular permeability, and unrecognized hypovolemia.