Focal glomerulosclerosis in children: an Argentinian experience

Incidence and Pathological Patterns of Nephrotic Syndrome among Infants and Children: A Systematic Review

Nephrotic syndrome (NS) is known to be a prevalent chronic illness in young patients. Periorbital swelling in children with this condition is a recurring symptom, either with or without generalized edema. The current study aimed to examine the incidence and pattern of nephrotic syndrome in infants and children by thoroughly examining the recently available literature. A thorough search of PubMed, SCOPUS, Web of Science, Science Direct, and Google Scholar was conducted, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) model, to find pertinent material. The Rayyan software (Qatar Computing Research Institute, Ar-Rayyan, Qatar) was utilized during the whole process. Data from a total of 1418 patients from nine trials were considered in this study. Numerous factors influenced the incidence, mean age, sex dominance, and histological patterns in various sample groups. The current findings conclude that variations in socioeconomic, regional, and genetic factors influence the development and pattern of these diseases. The prevalence of pediatric renal disorders differs throughout countries. Season of occurrence, response to corticosteroid treatment, and histopathologic findings appear to differ amongst the diagnosed cases.

Indications for kidney biopsy in idiopathic childhood nephrotic syndrome

BACKGROUND

Most cases of childhood nephrotic syndrome (NS) are due to minimal change disease (MCD), while a minority of children have focal segmental glomerulosclerosis (FSGS) and an unfavorable clinical course, requiring a kidney biopsy to confirm diagnosis. We hypothesized that clinical characteristics at diagnosis and initial response to corticosteroid treatment accurately predict FSGS and can be used to guide consistent practice in the indications for kidney biopsy.

METHODS

This was a case control study (1990-2012). Inclusion criteria included age 1-17 years, meeting the diagnostic criteria for NS, and having biopsy-proven FSGS or MCD. Clinical characteristics at diagnosis included age, kidney function [estimated glomerular filtration rate (eGFR)], hypertension, hematuria, nephritis (reduced eGFR, hematuria, hypertension), and response to steroids.

RESULTS

From a total of 169 children who underwent kidney biopsy for NS we included 65 children with MCD and 22 with FSGS for analysis. There were no significant between-group differences in age, sex, or eGFR at the time of diagnosis. The FSGS group had a higher proportion of hypertension (40 vs. 15%; p = 0.02), hematuria (80 vs. 47%; p = 0.01), and nephritis (22 vs. 2%; p = 0.004) and was more likely to be steroid resistant after 6 weeks of treatment than the MCD group (67 vs. 19%; p < 0.001). As predictors of FSGS, hematuria had a high sensitivity of 0.80 [95% confidence interval (CI) 0.56-0.93] and low specificity of 0.53 (95% CI 0.39-0.66), nephritis had a low sensitivity of 0.22 (95% CI 0.07-0.48) and high specificity of 0.98 (95% CI 0.88-0.99), and steroid resistance had a low sensitivity of 0.67 (95% CI 0.43-0.85) and high specificity of 0.81 (95% CI 0.68-0.90). The combination of steroid resistance after 6 weeks of therapy and/or nephritis at diagnosis yielded the optimal sensitivity and specificity at 0.80 (95% CI 0.56-0.93) and 0.75 (95% CI 0.60-0.86), respectively, confirmed by the highest receiver operator characteristic area under the curve of 0.77.

CONCLUSION

Steroid resistance after 6 weeks of therapy and/or nephritis at initial presentation is an accurate predictor of FSGS in children with NS and will be used as the indication for kidney biopsy in our newly developed clinical pathway. This approach will maximize the yield of diagnostic FSGS biopsies while minimizing the number of unnecessary MCD biopsies.

Corticosteroid-resistant nephrotic syndrome with focal and segmental glomerulosclerosis : an update of treatment options for children

Corticosteroid-resistant nephrotic syndrome (CRNS) with focal and segmental glomerulosclerosis (FSGS) is a heterogeneous disorder and the most severe and frequent type of all glomerulopathies in children leading to end-stage renal failure. The podocyte is at the center of development and progress of FSGS; this unique cell type plays a major role in the integrity of glomerular structure and permeability. The rate of complete remission of CRNS after induction therapy using different immunosuppressant agents is reported to range between 30% and 84%, depending on the treatment schedule and on the underlying defects of FSGS. Children with genetic types of FSGS barely respond to immunosuppressant therapies and over-treatment prior to transplantation should be avoided. The response of children with an idiopathic type of FSGS to immunosuppressants is superior to those with genetic FSGS. However, many children with idiopathic FSGS do not enter complete remission if they are under-treated, for example, with short-term immunosuppressant monotherapies. If immunosuppressant treatment fails, these patients will have to undergo renal transplantation. However, as unknown pathogenetic mechanisms may persist, more than one-third of these patients with idiopathic FSGS develop a rapid recurrence of CRNS that responds poorly to further long-term therapeutic attempts. In contrast with previously published data, this review takes into account recently identified genetic etiologies of CRNS, and superior results with long-term combination therapy in idiopathic forms to avoid over- and under-treatment.

Primary focal segmental glomerular sclerosis in children: clinical course and prognosis

To review the clinical course and identify prognostic factors, we retrospectively analyzed 92 children with steroid-resistant primary focal segmental glomerulosclerosis (FSGS). The mean age of onset was 80.4+/-42.4 months. The mean follow-up duration was 98.2+/-63.3 months. Eighty-five patients presented with nephrotic syndrome and seven presented with asymptomatic proteinuria. Thirty-three patients were initial responders to steroid treatment (late non-responders) and 59 were initial nonresponders. At last follow-up, 36 patients (39.1%) were in complete remission, and 29 (31.5%) progressed to chronic renal failure (CRF). Renal survival rates at 5, 10, and 15 years were 84, 64, and 53%, respectively. By morphological classification, there were tip variants (6.1%), collapsing variants (10.6%), cellular variants (1.5%), perihilar variants (9.1%), and NOS (not otherwise specified, 72.7%). Among the variants, there were no significant differences in age of onset, degree of proteinuria, response to treatment, or progression to CRF. Poor prognostic factors for CRF included: asymptomatic proteinuria at presentation, initial renal insufficiency, higher segmental sclerosis (%), severe tubulointerstitial change, initial nonresponse, and absence of remission. In the multivariate analysis, an increase in the initial serum creatinine and resistance to treatment were independent risk factors for CRF. A more prolonged use of corticosteroid therapy and early introduction of cyclosporin A (CsA) may improve the prognosis for primary FSGS in patients with initial steroid nonresponsiveness.

Predictive factors of chronic kidney disease in primary focal segmental glomerulosclerosis

Renal histological features of focal segmental glomerulosclerosis (FSGS) are found in 75% of pediatric patients with steroid-resistant nephrotic syndrome. In order to evaluate the predictive factors of chronic kidney disease (CKD), we retrospectively reviewed the records of 110 children with biopsy-proven FSGS admitted between 1972 and 2004. Renal survival was analyzed by the Kaplan-Meier method and Cox's regression model. Two multivariate models were developed: (1) from the onset of symptoms to the occurrence of CKD and (2) from the time of renal biopsy to CKD. Mean follow-up time was 10 years [standard deviation ((SD) 5.5], and 24 patients (21.8%) progressed to CKD. At baseline, after adjustment three variables remained as independent predictors of CKD: age >6.5 years (RR=3.3, 95% CI=1.3-7.8), creatinine >1 mg/dl (RR=2.5, 95% CI=0.97-6.5), and non-response to steroids (RR=7.3, 95% CI=2.7-19.7). In a model with continuous variables only age and non-response to steroids were associated with CKD. At the time of renal biopsy, after adjustment two variables remained as independent predictors of CKD: hematuria (RR=3.0, 95% CI=1.2-7.3) and creatinine >0.8 mg/dl (RR=4.3, 95% CI=1.7-10.6). In a model with continuous variables four factors predicted CKD: age, creatinine, hematuria, and percentage of global sclerosis.

Clinical course of 110 children and adolescents with primary focal segmental glomerulosclerosis

The purpose of this retrospective cohort study was to report the clinical course of children and adolescents with primary focal segmental glomerulosclerosis (FSGS). The records of 110 patients with biopsy-proven FSGS admitted between 1972 and 2004 were retrospectively reviewed. Demographic, clinical and laboratory data were recorded and histopathological data were reanalyzed by one pathologist who had no information about the outcome of the patients. Renal survival analysis was performed using the Kaplan-Meier method. Differences between subgroups (response to corticosteroids) were assessed by the two-sided log rank test. The median age at admission was 5 years (range: 1-15 years). Forty-two patients (38.2%) presented with hematuria at admission, and 55 (50%) presented blood pressure levels above the 95th percentile. Mean follow-up time was 10 years (SD 5.5). Twenty-four patients (21.8%) presented chronic kidney disease (CKD). It was estimated that the probability of CKD was 8% at 5 years, 17% at 10 years, and 32% at 15 years after diagnosis of nephrotic syndrome. In conclusion, on the basis of the clinical and histological characteristics observed, apparently our cohort of idiopathic FSGS is comparable with other published series. However, the long-term overall renal survival seems to be better in our cohort.

Cyclophosphamide in the treatment of focal segmental glomerulosclerosis

Prednisone is the initial treatment of primary focal segmental glomerulosclerosis. However, when immunosuppressive agents in combination with steroids are used in the treatment of prednisone-dependent and prednisone-resistant patients the remission rate is variable. We report a long-term trial using cyclophosphamide (2.0 to 3.0 mg/kg body weight for 12 weeks) in combination with prednisone (1.0 to 2.0 mg/kg body weight), as compared with prednisone alone for the treatment of prednisone-resistant and frequently relapsing nephrotic syndrome and focal segmental glomerulosclerosis. Fifty-four patients (34 males and 20 females) with a diagnosis of idiopathic nephrotic syndrome and focal segmental glomerulosclerosis, followed-up for an average of 86.1 +/- 82.4 months, were evaluated. Complete remission occurred in 20.4% and partial remission in 14.8% of the patients treated with steroids and in 26.7 and 20.0% of the patients treated with cyclophosphamide + prednisone, respectively. Of the 24 prednisone-resistant patients treated with steroids in combination with cyclophosphamide, 33.3% obtained a complete/partial response. At the time of final evaluation, 25% of the patients treated with prednisone and 10.0% of those treated with prednisone in combination with cyclophosphamide had reached end-stage renal disease. Persistent nephrotic syndrome and progressive renal insufficiency were more frequently observed among the patients treated with prednisone alone (50.0 vs 33.3% and 33.3 vs 16.7%, respectively). The treatments were well tolerated and no patient experienced adverse reactions requiring discontinuation of medications. Although open-label and non-randomized, the present trial showed that cyclophosphamide is a reasonable choice for the treatment of primary focal segmental glomerulosclerosis and prednisone-resistant nephrotic syndrome.

Focal segmental glomerulosclerosis

Over the last 2 decades, we have learnt that focal segmental glomerulosclerosis (FSGS) is a ubiquitous phenomenon underlying the progressive deterioration of many different types of renal diseases in both pediatric and adult populations. FSGS may also be the primary renal lesion, whether in new disease entities such as glycogen storage disease and human immunodeficiency virus infection, or in idiopathic FSGS. Although the mechanism which triggers the development of primary FSGS still remains unknown, laboratory and clinical studies have identified several key pathophysiological events leading to end-stage renal disease. While therapeutic modalities have not changed remarkably, a recent study, although uncontrolled, demonstrated an impressive efficacy of intravenous steroid pulse therapy in inducing remission. Nevertheless, it remains largely unknown whether such a forced remission decreases the overall risk of developing chronic renal failure. Studies have revealed an important pathophysiological role of angiotensin and the therapeutic efficacy of angiotensin converting enzyme inhibitors in progressive loss of renal function in diseases where glomerulosclerosis is secondary; however, it remains to be verified whether these results hold true in primary FSGS. As a result of the improvement in allograft survival rate, the benefit of renal transplant outweighs the risk of recurrence of FSGS, hence transplantation continues to be a vital therapy for FSGS patients who have reached renal failure. Thus, FSGS is not one disease, but rather a range of lesions seen in many settings. The type of lesions and the patient's unique genetic factors contribute to prognosis, and also may dictate choice of optimum therapy.