Focal segmental glomerulosclerosis with and without nephrotic syndrome in children

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.

Podocyte and endothelial injury in focal segmental glomerulosclerosis: an ultrastructural analysis

Podocyte injury contributes to the development of focal segmental glomerulosclerosis (FSGS). Endocapillary hypercellularity, which is one of the pathological characteristics of FSGS, suggests that glomerular endothelial injury may also be involved in the pathogenesis of FSGS. In electron micrographs of patients with FSGS (n = 43), we conducted morphometric measurements of foot process width (FPW) and podocyte detachment (PD) as markers of podocyte injury and subendothelial widening (SW) of the glomerular basement membrane as a marker of endothelial injury and compared them to those in patients with minimal change nephrotic syndrome (MCNS; n = 11) and control kidney donors (n = 5). Associations between ultrastructural and clinical parameters were analyzed according to the FSGS variants defined by the Columbia classification. FPW was significantly higher in the FSGS group than that in the MCNS and control groups, particularly in the collapsing, tip, and cellular variants of FSGS. Percentage of glomerular basement membrane (GBM) length showing PD and SW was significantly increased in the FSGS group, especially in the collapsing, cellular, and not otherwise specified variants. In FSGS, FPW was inversely correlated with disease duration, but not with proteinuria. Finally, the percentage of GBM length with SW significantly correlated with clinical parameters indicative of poor prognosis, such as lower remission rate and lower estimated glomerular filtration rate at the final observation. Quantitative measurement of podocyte and endothelial injury by electron microscopy might be useful for evaluating histological activity and predicting prognosis in FSGS.

Success with plasmapheresis treatment for recurrent focal segmental glomerulosclerosis in pediatric renal transplant recipients

FSGS recurs in approximately 30% of transplanted kidneys and may lead to graft loss. We retrospectively examined the efficacy of early and intensive PP without additional IS in pediatric kidney transplant patients with recurrent FSGS at our center. Seven of 24 patients (29%) had nephrotic proteinuria and histologic evidence of FSGS recurrence within 1-5 days post-transplantation. PP was initiated early after transplantation and initially performed daily until sustained decline in proteinuria. PP frequency was then individually tapered according to proteinuria. Recurrent FSGS in all seven patients responded to a four- to 32-wk course of PP. Two of seven patients had a second recurrence of FSGS, and both recurrences remitted after an additional 3-6 wk of PP. Median observation period was 4.5 yr (0.8-16.3 yr). Complete remission of recurrent FSGS has been sustained in all seven patients, and all patients have stable graft function with recent plasma creatinine <1.5 mg/dL in six of seven patients. Most recent urine protein/creatinine is 0.13-0.61 mg/mg in six of seven patients. One patient has heavy proteinuria secondary to chronic allograft nephropathy 16 yr post-transplant. Intensive and prolonged PP, when initiated early in the post-operative period, is effective in treating recurrent FSGS and preventing graft loss without the use of additional immunosuppressants.

Primary focal segmental glomerulosclerosis in Egyptian children: a 10-year single-centre experience

Primary focal segmental glomerulosclerosis (FSGS) in children accounts for 7-20% of all cases of idiopathic nephrotic syndrome (NS). To evaluate the clinical course of children with primary FSGS, the records of 72 patients with biopsy-proven FSGS admitted between 1995 and 2008 were retrospectively analysed. Forty-eight patients were male (66.7%). The mean age at presentation was 76.5 +/- 54 (range 12-192) months. The mean duration of follow-up was 76.3 +/- 42 (range 9-156) months. Seventeen patients (23.6%) presented with gross haematuria at initial presentation, 15 (20.8%) presented with hypertension and 10 patients (14%) presented with chronic renal insufficiency (CRI). The initial response to oral prednisolone was steroid resistance in 63 patients (87.5%) and steroid dependence in 4 patients (5%), while 5 patients (6.9%) were biopsied from the start because of atypical presentation. According to pathological classification, there were the tip variant (2%), collapsing variant (6%), perihilar variant (7%) and NOS (not otherwise specified; 85%). At the last clinical visit, 12 patients (16.7%) were in complete remission and 11 (15.3%) had progressed to CRI. Renal survival rates at 5 and 10 years were 93% and 68%, respectively. In conclusion, in this study we had a low percentage of FSGS, and fewer patients presenting with gross haematuria and hypertension compared with previous reports. In addition, the short-term overall renal survival seems to be better in our cohort.

Recurrence of focal segmental glomerulosclerosis in renal allograft: an in-depth review

Focal segmental glomerulosclerosis is a major cause of chronic kidney disease requiring transplantation in children. Recurrence rate in the renal allograft transplantation is as high as 50%. Recurrence of FSGS is associated with renal dysfunction and early graft loss. To date, there is no established therapy for recurrent FSGS after renal transplant. We have reviewed the current English literature in order to summarize current practices with emphasis on graft outcome. We conclude that despite multiple approaches to the post transplant management of recurrent FSGS, none have been shown to be consistently beneficial. Currently, pheresis combined with high dose anti-calcineurin with or without rituximab seems to be the most promising. Further controlled studies are needed to define the optimal therapeutic regimens to treat recurrent of FSGS.

Obesity-related nephropathy in children

Concurrent with the global obesity epidemic, there is an increasing number of people of all ages developing chronic kidney disease associated with obesity. In adults, the definition of obesity is a BMI greater than 30 kg/m2. Whereas, in children, a BMI greater than the 85th percentile for age is considered overweight and greater than the 95th percentile is classified as obese. Clinical and pathologic characteristics of a distinct nephropathy have emerged independent of that of diabetic or hypertensive glomerulosclerosis. These include a silent presentation in an obese individual with heavy proteinuria, normal serum albumin and the absence of edema. Renal pathologic findings are notable for mesangial matrix expansion, glomerular hypertrophy and reduced density of podocytes with detachment of foot processes from the glomerular basement membrane. These findings are frequently associated with the development of secondary focal segmental glomerulosclerosis. Obesity alone does not appear to be the sole mediator of this nephropathy. It is most likely the ‘second hit’ for individuals who have congenital or acquired reduced nephron mass as well as an inherited genetic vulnerability to the metabolic consequences imposed by cytokines released by adipose tissue. In children, those born of low birthweight, whether small for gestational age and/or preterm, are likely to have reduced nephron mass as well as an increased tendency for early insulin resistance and the development of obesity and the metabolic syndrome. This in turn is perpetuated by the practice of feeding high-calorie fortified formulas to low-birthweight infants. Rapid catch-up growth, early obesity and insulin resistance are major contributors to the emergence of obesity-related glomerulopathy in children and adolescents. Early detection requires recognizing the demographics of high-risk infants and monitoring them for the development of hypertension, elevated glomerular filtration rate, hyperfiltration and proteinuria. After 6 months of age, angiotensin-blocking agents may be used to control blood pressure, glomerular hyperfiltration and proteinuria. If obesity is present, a comprehensive program of weight loss, including diet and exercise, should be the mainstay of treatment. In older children and adolescents, lipid-lowering medications may be indicated. With morbid obesity, bariatric surgery may be an option.

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.

Angiotensin antagonists and steroids in the treatment of focal segmental glomerulosclerosis

The use of angiotensin converting enzyme inhibitors (ACEIs) along with good blood pressure control have been shown to significantly decrease the level of proteinuria and slow the progression of renal insufficiency in patients with nondiabetic glomerular disease including focal segmental glomerulosclerosis (FSGS). Thus, this should be part of the therapeutic approach for all proteinuric patients with FSGS and should be considered the mainstay of therapy for patients with FSGS secondary to conditions associated with hyperfiltration and/or reduced nephron mass and those patients with nonnephrotic primary FSGS. However, nephrotic patients with primary FSGS may continue to have marked proteinuria and progression of renal disease despite these measures and thus require a more aggressive approach with the use of steroids and immunosuppressive agents. Although primary FSGS was once thought to be a steroid-nonresponsive lesion, recent experience has provided a note of optimism in the use of steroids and immunosuppressive agents in treating this otherwise progressive glomerulopathy. As a result, a course of steroid therapy in primary FSGS is now warranted in nephrotic patients with reasonably well preserved renal function in whom it is not otherwise contraindicated.

Pathologic classification of focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is defined as a clinical-pathologic syndrome manifesting proteinuria and focal and segmental glomerular sclerosis with foot process effacement. The pathologic approach to the classification of FSGS is complicated by the existence of primary (idiopathic) forms and multiple subcategories with etiologic associations, including human immunodeficiency virus (HIV)-associated nephropathy, heroin nephropathy, familial forms, drug toxicities, and a large group of secondary FSGS mediated by structural-functional adaptations to glomerular hyperfiltration. A number of morphologic variants of primary and secondary focal sclerosis are now recognized, including FSGS not otherwise specified (NOS), perihilar, cellular, tip, and collapsing variants. The defining features of these morphologic variants and of the major subcategories of FSGS are discussed with emphasis on distinguishing light microscopic patterns and clinical-pathologic correlations.

Idiopathic focal segmental glomerulosclerosis

Idiopathic focal segmental glomerulosclerosis (FSGS) is a primary glomerular disease that essentially represents a form of chronic, progressive renal fibrosis for which there is no discernible cause. Often presenting with or eventually manifesting the nephrotic syndrome, this disease is increasing in incidence in both children and adults. Therapy continues to be a challenge, although some patients clearly respond to corticosteroids or cyclosporine with a decrease in, or remission of, proteinuria. A favorable response is associated with a decreased likelihood of progression to kidney failure. Given our clinical experience and recent advances in understanding the genetics of FSGS, a stochastic model of disease pathogenesis can be proposed.

Proteinuria and focal segmental glomerulosclerosis in severely obese adolescents

OBJECTIVE

To describe the clinical and laboratory features of obesity associated proteinuria and focal segmental glomerulosclerosis.

STUDY DESIGN

The patients were seen over a 12-year period at two large children's hospitals. Renal biopsies, performed for the diagnosis of unexplained heavy proteinuria and prepared for light, immunofluorescent, and electron microscopy, were read independently by two pediatric pathologists. Blood pressure, body mass index, serum levels of creatinine, albumin, and cholesterol, and 24-hour urinary protein were measured.

RESULTS

Seven African American adolescents were identified with obesity-associated proteinuria, which was characterized by severe obesity (120 +/- 30 kg), markedly elevated body mass index (46 +/- 11), mild hypertension (134/74 +/- 10/18 mm Hg), slightly low to normal serum albumin levels (3.6 +/- 0.2 g/dL), moderately elevated serum cholesterol levels (196 +/- 60 mg/dL), and elevated 24-hour protein excretion (3.1 +/- 1.3 g/dL). Calculated creatinine clearance was normal in 6 patients and decreased in one. Typical renal histologic features included glomerular hypertrophy, focal segmental glomerulosclerosis, increased mesangial matrix and cellularity, relative preservation of foot process morphology, and absence of evidence of inflammatory or immune-mediated pathogenesis. One patient showed a dramatic reduction in proteinuria in response to weight reduction. Three patients who were given angiotensin-converting enzyme inhibitors had reduced urinary protein losses from 2.9 g to 0.7 g per day. One patient developed end-stage renal disease.

CONCLUSION

Obese adolescents should be monitored for proteinuria, which has distinct clinical and pathologic features and may be associated with significant renal sequelae. Such proteinuria may respond to weight reduction and/or treatment with angiotensin-converting enzyme inhibitors.

The treatment of primary focal segmental glomerulosclerosis

Nephrotic patients with primary focal segmental glomerulosclerosis (FSGS) have a poor prognosis with 50% progressing to end stage renal disease (ESRD) over 3 to 8 years. The achievement of a remission in proteinuria has been associated with a significantly improved renal survival as compared to those patients not attaining a remission. Unfortunately, spontaneous remissions are rare in FSGS, and the response to therapy has historically been poor. Recent experience with more aggressive immunosuppressive therapy has lead to an increase in the remission rate for FSGS patients and given rise to optimism in the treatment of this glomerulopathy.

The nonspecificity of focal segmental glomerulosclerosis. The defining characteristics of primary focal glomerulosclerosis, mesangial proliferation, and minimal change

We performed a detailed clinical review and pathologic analysis of the kidney biopsies of 134 children with nephrotic syndrome or asymptomatic proteinuria. This analysis challenges some of our concepts about the classification of conditions associated with these disorders. The presence of focal segmental sclerotic lesions does not define a unique disorder in childhood. Some children with such lesions will have unaffected glomeruli that are ultrastructurally completely normal. These patients, predominately black adolescents, present either with nephrotic syndrome or asymptomatic proteinuria. We classify this disorder as primary focal segmental glomerulosclerosis (FSGS) and have never found it to recur after transplantation. Most other children with FSGS have 1 of 2 specific glomerulopathies. Those with minimal change have generalized fusion of podocyte foot processes. Those with mesangial proliferation have similar foot process changes combined with mesangial expansion and proliferation and, frequently, thinning of the lamina densa and tubuloreticular inclusions. The presence of segmental lesions in these glomerulopathies appears to be nothing more than a marker of severity. Children with these glomerulopathies are generally younger white children, virtually all of whom have nephrotic syndrome. These disorders have a strong propensity to recur after transplantation. The presence of mesangial labeling of IgM or C1q has no significance in any of these 3 disorders. The classification of disorders associated with nephrotic syndrome or asymptomatic proteinuria must concentrate less on the presence or absence of focal sclerosis and more on the histologic appearance of the rest of the glomeruli.

Cyclophosphamide does not benefit patients with focal segmental glomerulosclerosis. A report of the International Study of Kidney Disease in Children

Sixty children, with biopsy diagnosed focal segmental glomerulosclerosis (FSGS) and with unremitting nephrotic syndrome despite intensive therapy with adrenocortical steroids, were randomly allocated into a clinical trial comparing prednisone, 40 mg/m2 on alternate days for a period of 12 months (control group), with the same prednisone regimen plus a 90-day course of daily cyclophosphamide, 2.5 mg/kg in a single morning dose (experimental group). One-quarter of the children in each group had complete resolution of proteinuria. The proportions of children with increased, unchanged, and decreased proteinuria by the end of the study were the same in the two groups. Treatment failure was defined as an increase in serum creatinine of 30% or more or greater than 0.4 mg/dl, or onset of renal failure. Treatment failure occurred in 36% of the control group and 57% of the experimental group (P > 0.1). Five patients died during the trial, 3 in the experimental group and 2 in the control group. A Kaplan-Meier survival analysis revealed no significant differences between the two groups. Cyclophosphamide therapy for children with steroid-resistant FSGS is not recommended.

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.

Primary focal segmental glomerular sclerosis in adults: prognostic value of histologic variants

Primary focal segmental glomerular sclerosis (FSGS) is a clinicopathologic syndrome in which variable amounts of proteinuria are associated with the renal biopsy finding of segmental glomerular scarring in some, but not all, of the glomeruli. Additional histologic features have been described in FSGS, including the position of the scar relative to the vascular and tubular pole of the glomerulus, foam cells, hyalinosis, mesangial deposits of immunoglobulin M, diffuse mesangial hypercellularity, glomerular visceral epithelial cell hyperplasia and hypertrophy, and the extent of associated interstitial fibrosis and tubular atrophy. We performed a retrospective study on 81 patients with biopsy-proven, primary FSGS to determine whether any of the histologic features of FSGS correlated with renal function at the time of biopsy and the incidence of end-stage renal disease at follow-up. Sixty patients were nephrotic and 21 had nonnephrotic proteinuria. Only the degree of interstitial fibrosis correlated with the initial serum creatinine (r = 0.536) and none of the histologic features predicted the presence of nephrotic-range proteinuria at the time of biopsy. Segmental scars involved 21% +/- 14% of the glomeruli per biopsy specimen, but their position within the glomerulus was uniform in only 13% of the cases. Diffuse mesangial hypercellularity was present in 17% of the biopsy specimens, and glomerular epithelial cell lesions were present in 57% of the biopsy specimens. Multivariate analysis showed that only the degree of interstitial fibrosis predicted end-stage renal disease in all 81 patients and in the 60 patients with nephrotic-range proteinuria. The current data do not support different therapeutic approaches in primary FSGS based on histologic subtypes.

A quantitative analysis of the glomeruli in focal segmental glomerulosclerosis

Quantitative analysis of the glomerular area, mesangial matrix and mesangial cells was performed using renal biopsy specimens from 22 children with focal segmental glomerulosclerosis (FSGS) and 20 with minimal change nephrotic syndrome (MCNS). Non-sclerotic glomeruli were examined. All children in both groups showed nephrotic syndrome at the time of biopsy. Children with benign haematuria were examined as controls. Glomerular area increased with age in the FSGS, MCNS and control groups. The glomerular area was significantly greater in FSGS (1.5 +/- 0.4 x 10(4) microns 2) than in MCNS (1.2 +/- 0.2 x 10(4) microns 2) or in controls (1.2 +/- 0.3 x 10(4) microns 2) (P < 0.05). Mesangial matrix was increased with age in the three groups. The mesangial matrix was significantly increased in FSGS (28.3 +/- 4.0%; mesangial matrix area/glomerular area) compared with MCNS (24.9 +/- 4.1%) and controls (23.0 +/- 3.0%) (P < 0.01). These findings suggest that both glomerular hypertrophy and mesangial matrix increase in non-sclerotic glomeruli in FSGS may lead to glomerular sclerosis.

Comparison of asymptomatic and symptomatic childhood glomerulonephritis progressing to renal failure: a report of Kyushu Pediatric Nephrology Study Group

We evaluated the clinicopathological features and the outcome of 33 children with primary glomerulonephritis (GN) as the cause of renal failure; 17 had asymptomatic (ASP) haematuria and/or proteinuria and the remaining 16 had symptoms suggestive of GN. The renal histology in the ASP group indicated IgA GN in 6 children, focal segmental glomerular sclerosis (FSGS) in 4, diffuse proliferative GN (DPGN) in 3, membranous GN (MGN) in 1, membranoproliferative GN (MPGN) in 1 and diffuse sclerosing GN in 2. In the symptomatic (SYP) group, FSGS was evident in 9 children, DPGN in 3, MGN in 2, IgA GN in 1 and MPGN in 1. There was no difference in the histological severity between the two groups. Fourteen children in the SYP group had nephrotic syndrome (NS) and/or hypertension at their initial visits. Only 4 children in the ASP group showed NS or hypertension during the period of follow-up. Eleven children in the ASP group and all in the SYP group were treated with immunosuppressive and/or antihypertensive drugs, but these did not improve the prognosis of the ASP children compared with those in the SYP group. There was no significant difference in the mean duration between the onset of the disease and the start of dialysis in these two groups. In conclusion, it is questionable whether the urinary mass screening programme in Japan will alter the outcome of children with GN.

Isolated proteinuria in children. Natural history and indications for renal biopsy

The significance of isolated proteinuria in pediatric patients is uncertain. Therefore, we retrospectively studied all children evaluated for this urinary abnormality during the 6-year period from 1986 to 1992. Thirty-one patients (19 males), age 2 to 20 years, were identified as having isolated proteinuria that had persisted for a mean interval of 9.6 +/- 1.9 (SEM) months. The diagnosis was based upon the presence of a urine protein:creatinine ratio > 0.2 in an early-morning specimen. None of the patients had hematuria, edema, or azotemia. Seventeen children underwent a renal biopsy. There was no difference between the patients who were biopsied and those who were not with respect to age, magnitude of proteinuria, glomerular filtration rate (GFR), or serum albumin and cholesterol concentrations. The renal histopathology revealed focal segmental glomerulosclerosis (FSGS) (n = 8), membranous nephropathy (n = 1), postinfectious nephritis (n = 2), focal global glomerulosclerosis (FGGS) (n = 1), and normal kidney tissue (n = 5). Twelve of the patients who did not undergo a kidney biopsy and four of the five children with a normal renal biopsy were followed for at least 12 months; there was complete resolution of the proteinuria in 11 (69%) of these patients. The level of proteinuria did not predict the presence or absence of important kidney disease. However, if isolated proteinuria persists for more than 1 year, it is then unlikely to spontaneously remit and a renal biopsy is indicated to clarify the nature of any underlying glomerulopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary focal segmental glomerulosclerosis: clinical course and response to therapy

Primary focal segmental glomerulosclerosis (FSGS) is a lesion associated with a poor prognosis and results in end-stage renal disease after 5 to 10 years. Based on past experience, many nephrologists have considered primary FSGS a lesion that is steroid resistant and therefore are reluctant to offer steroids as treatment. Recent data, however, have demonstrated that patients with primary FSGS have a response to steroid therapy that is considerably better than had been described. Thus, it may be that nephrologists have been more "steroid reluctant" than the lesion is steroid resistant. To better understand this issue we review the clinical course and response to therapy in patients with primary FSGS.

Focal glomerulosclerosis in children: an Argentinian experience

Twenty-six children presenting with idiopathic nephrotic syndrome and a histological diagnosis of focal glomerulosclerosis were studied retrospectively to evaluate their response to treatment, outcome and clinicopathological correlations. Twenty-two patients (84.6%) were steroid resistant; of these, 8 of the 19 with focal segmental glomerulosclerosis and 2 of the 3 with focal global glomerulosclerosis responded to cyclophosphamide (CY) within 16 weeks of starting therapy. Seven patients relapsed after a CY-induced remission, but 5 of them became steroid responsive. After an average follow-up of 83 months, 17 patients are in remission with normal renal function, 3 patients have persistent nephrotic range proteinuria and 6 patients are in chronic renal failure. Persistence of proteinuria, a high percentage of segmentally sclerotic glomeruli and diffuse mesangial proliferation were indicators of poor prognosis. We believe longer courses of CY therapy than those traditionally utilized are responsible for the relatively good results in our patients.

Asymptomatic constant isolated proteinuria in children

The clinical features, renal biopsy findings, and subsequent course in 53 children with asymptomatic constant isolated proteinuria were studied retrospectively (1) to determine the prevalence of renal pathologic abnormalities among these children, (2) to identify those clinical characteristics that may enable recognition of children with an increased likelihood of having renal pathologic abnormalities, and (3) to assess the clinical course. All biopsy specimens were examined by light, immunofluorescence, and electron microscopy. Twenty-five patients (47%) had significant glomerular changes (15 had focal segmental glomerulosclerosis, 4 IgA nephropathy, 3 diffuse mesangial proliferative glomerulonephritis without IgA deposition, and 3 membranous glomerulonephritis), and 28 had minimal glomerular changes. There were no differences between the patients with significant glomerular changes and those with minimal glomerular changes with regard to clinical and laboratory findings except for a predominance of boys in the former group. At the latest follow-up, seven patients with significant glomerular changes, but none with minimal glomerular changes, had chronic renal impairment. Because of the high incidence of significant glomerular changes and the high rate of progression to chronic renal impairment, we believe that a renal biopsy is indicated for a child with asymptomatic constant isolated proteinuria.

The glomerular changes in children with reflux nephropathy

While heavy proteinuria and focal segmental glomerulosclerosis (FSGS) are well-recognized features of progressive reflux nephropathy in adults, little is known of their early evolution. We have studied the glomerular changes in renal biopsy specimens obtained from 24 patients aged 5.2-18.8 years, in whom urinary protein excretion was measured as early morning urine protein creatinine ratios, using the Coomassie blue dye-binding method. Segmental sclerotic lesions were found in eight biopsies and traced through serial sections to a hilar origin in every instance. There was a strong positive correlation between the extent of glomerular involvement and the amount of proteinuria (P less than 0.0001). Parahilar hyaline deposits were observed in 16 biopsies, including five of the eight showing FSGS. All unsclerosed glomeruli were enlarged, and the hilar arterioles showed both enlargement and thickening, their walls frequently containing subendothelial hyaline deposits. Since in most patients renal function was comparatively well preserved, despite extensive loss of renal substances, we believe that these glomerular and vascular changes represent the stages in the evolution of hyperfiltration. Microproteinuria is the earliest clinical manifestation of FSGS, and should be sought routinely in all patients with reflux nephropathy.

Evaluation of chlorambucil therapy in steroid-dependent and cyclophosphamide-resistant children with nephrosis

A prospective study was performed to evaluate the efficacy of chlorambucil in inducing long-term remission in children with steroid-dependent or cyclophosphamide-resistant primary nephrotic syndrome (NS). The 16 steroid-dependent children had a relapse rate of 5.3/patient per year (range 4-8) and a mean age of 8.4 years (range 2-13). The chlorambucil dosage was 0.2 mg/kg per day for a total of 8 weeks. Nine patients (56%) remained in complete remission for an average of 39.2 months (range 16-70). The interval to the first relapse in the remaining 7 ranged from 4 to 41 months and the relapse rate decreased significantly to 0.6 relapses/patient per year (P less than 0.05). Five children had steroid- and cyclophosphamide-resistant NS, 4 with focal segmental glomerulosclerosis and 1 with mesangiol proliferative glomerulonephritis. Chlorambucil was given in a dose of 0.2 mg/kg per day for 8-16 weeks. Complete remission was obtained in 4 patients; 2 patients relapsed. No serious long-term complications were observed in our patients.

Asymptomatic haematuria and proteinuria: renal pathology and clinical outcome in 54 children

In a mass screening programme, 54 children with haematuria and proteinuria were detected and evaluated by clinical findings and renal histology. IgA glomerulonephritis (GN) occurred in 29 patients, diffuse mesangial proliferative GN (DPGN) in 16, membranous GN (MGN) in 4, membranoproliferative GN (MPGN) in 3, and focal segmental glomerular sclerosis (FSGS) was seen in 2. Of the 35 children with proteinuria less than or equal to 1 g/m2 per day, 21 with IgA GN and 14 with DPGN had only mild to moderate glomerular changes. None of these children had developed renal impairment after a mean period of 6.5 years (range 5-10 years). On the other hand, 8 children with IgA GN, 2 with DPGN, 4 with MGN, 3 with MPGN, and 2 with FSGS had proteinuria that exceeded 1 g/m2 per day. The biopsy specimens from these children showed moderate to severe glomerular changes, and 7 of these children had hypertension or renal impairment during the period of evaluation. This study suggests that a poor outcome correlates with the level of proteinuria and the severity of renal pathology in children with haematuria and proteinuria.

Focal segmental glomerulosclerosis in children: comparison of nonedematous and edematous patients

Persistent proteinuria without edema, associated with focal segmental glomerulosclerosis (FSGS), has been increasingly observed in our pediatric population. The clinical and pathological features and long-term outcome of these patients are poorly understood and less frequently reported. Ten nonedematous children (10.3 +/- 1.4 years) with proteinuria and FSGS are compared with 16 children (9.0 +/- 0.4 years) with FSGS and nephrotic syndrome (NS). Urinary protein excretion and serum cholesterol were statistically higher and serum albumin statistically lower in the children with FSGS-NS. The percentage of glomeruli with sclerosis was similar in the two groups. Mesangial proliferation was observed more frequently in the nephrotic children and focal or diffuse tubular atrophy more often in the nonedematous children with FSGS. Followup serum creatinines are more than 1 SD above the mean for age in 3 of 10 nonedematous patients with FSGS and 9 of 16 patients with FSGS-NS. Of 10 nonedematous patients with FSGS, 1 progressed to renal failure 20 months after diagnosis, while 3 of 16 patients with FSGS-NS progressed to renal failure. We conclude from these data that NS is a poor prognostic sign in FSGS in children and that neither the percentage of glomeruli with sclerosis nor the presence of tubular atrophy is predictive of NS in our patients.