The idiopathic nephrotic syndrome of childhood. A clinical reevaluation of 148 cases

Incidence and Relapse of Idiopathic Nephrotic Syndrome: Meta-analysis

CONTEXT

Idiopathic nephrotic syndrome (INS) in children is a disease with considerable morbidity, yet the incidence and risk for relapse have not been systematically reviewed.

OBJECTIVE

To estimate the overall pooled weighted incidence and risk for relapse of INS in children.

DATA SOURCES

Medline and Embase (until December 2020).

STUDY SELECTION

All studies reporting incidence (per 100 000 children per year) and/or risk for relapse (the proportion of patients who experience ≥1 relapse) of INS in children (age: <18 years) were eligible.

DATA EXTRACTION

After quality assessment, data were extracted: study (design, localization, and sample size) and patient (age, sex, steroid response, and ethnicity) characteristics, incidence, and risk for relapse.

RESULTS

After screening, 73 studies were included for analysis (27 incidence, 54 relapse). The overall pooled weighted estimate and corresponding prediction interval (PI) of the incidence was 2.92 (95% PI: 0.00-6.51) per 100 000 children per year. Higher incidences were found in non-Western countries (P < .001). Incidence tended to be lower in white children, but this was not significant. The overall pooled weighted estimate of the risk for relapse was 71.9% (95% PI: 38.8-95.5). Between 1945 and 2011, incidence did not change (P = .39), yet the risk for relapse decreased significantly (P = .024), from 87.4% to 66.2%.

LIMITATIONS

There was no full-text availability (n = 33), considerable heterogeneity, and limited studies from Africa, Latin America, and Asia.

CONCLUSIONS

INS has a low incidence with ethnic variation but high risk for relapse. Although corticosteroids have significantly reduced the risk for relapse, it remains unacceptably high, underscoring the need for alternative treatment strategies.

Management of nephrotic syndrome in children

Idiopathic childhood nephrotic syndrome generally has a favorable long-term prognosis. Prompt administration of and improved guidelines for monitoring therapy have decreased morbidity and mortality. The treatment goal is to induce prompt remission while minimizing complications and adverse events. Aggressive therapy induces remission and decreases the frequency of relapse in most patient populations; however, such treatment often results in unnecessary toxicity. We critically assessed the current clinical evidence that supports each pharmacologic therapy. For each drug regimen, the risks and monitoring parameters required to reduce complications and optimize therapy are discussed. Some of the treatments are the common corticosteroid approaches, cytotoxic therapies (chlorambucil, cyclophosphamide), cyclosporine, less frequently used drugs (e.g., levamisole), and experimental therapies. Further studies are needed to identify the most effective and least toxic therapeutic regimens for inducing and maintaining remission in children with nephrotic syndrome.

Evaluation of hematuria, proteinuria, and hypertension in adolescents

Signs or symptoms of renal disease in adolescents deserve prompt attention and appropriate evaluation. Adolescents are susceptible to a variety of urinary tract disorders. The key issue in the evaluation of hematuria or proteinuria in adolescents is the existence of concomitant signs of renal disease. For isolated hematuria or proteinuria, demonstration of persistence and a reasoned evaluation are in order. Hypertension in adolescents must be carefully documented and, when present, considered seriously. The fact that most teens with persistent elevated blood pressures have essential hypertension is still a great concern because for most of these adolescents the hypertension will be lifelong and, if left untreated, can be associated with significant morbidity and mortality in the adult years.

Cyclosporin A in refractory idiopathic nephrotic syndrome: 5 years clinical experience

The use of cyclosporin A (Cy A) in idiopathic nephrotic syndrome, particularly lesions of focal segmental glomerular sclerosis, is controversial. A retrospective study of 10 adult patients with nephrotic syndrome treated with Cy A was performed. Histological diagnosis was established in all patients: focal segmental glomerular sclerosis (n = 6), focal global sclerosis (n = 1), mesangial proliferative glomerulonephritis (n = 1), focal proliferative glomerulonephritis (n = 1) and minimal change disease (n = 1). All patients had previously received immunosuppressive therapy (duration of steroids 1-76 months; 35.0 +/- 12.1, mean +/- SEM). Cy A in a dose of 3-5 mg/kg/day, reduced proteinuria from 16.85 +/- 6.67 to 3.37 +/- 1.48 g/24 hours (P = 0.008), with an associated increase in serum albumin from 15.2 +/- 2.6 to 34.3 +/- 2.5 g/l (P < 0.001). In six patients steroid therapy was discontinued. Cy A was well tolerated for up to 5 years. There was no significant nephrotoxicity. In conclusion, Cy A was effective treatment of refractory idiopathic nephrotic syndrome, including those cases with focal segmental glomerular sclerosis.

Cyclosporine in idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome encompasses two main forms of glomerular diseases, minimal change nephropathy and focal segmental glomerulosclerosis. Minimal change nephropathy is a disease of children which generally responds to corticosteroids. After remission, however, many patients show frequent relapses or steroid dependency. In these patients, cyclosporine may obtain remission of proteinuria in 80% of cases, although relapse usually occurs when the drug is stopped. Focal glomerulosclerosis is generally resistant to corticosteroids. Under cyclosporine some 40% of patients may attain complete or partial remission of the nephrotic syndrome particularly if low-dose prednisone is associated. Relapse of proteinuria usually occurs after stopping the drug. As cyclosporine may expose to chronic nephrotoxicity some guidelines should be followed to prevent this complication: - the doses should not exceed 5 mg/Kg/day - they should be adjusted whenever an increase in plasma creatinine of > or = 30% over the baseline values occurs - treatment should be stopped if there is no response within 3 months - a careful monitoring of patient under the supervision of a clinician trained with the use of cyclosporine is necessary. The term idiopathic nephrotic syndrome (INS) defines the association of a nephrotic syndrome with non specific glomerular lesions, in the absence of immune complex deposition (1). On the basis of renal histology two main types of INS are recognized: minimal change nephropathy (MCN) and focal and segmental glomerular sclerosis (FSGS).

Treatment of the nephrotic syndrome with cyclosporin A

The three main causes of primary nephrotic syndrome are minimal change nephropathy, focal glomerulosclerosis and membranous nephropathy. Corticosteroids obtain remission of proteinuria in most patients with minimal change nephropathy. Many patients, however, show either frequent relapses or steroid dependency. A short course of cyclophosphamide or chlorambucil can achieve stable remission in many of these patients but alkylating agents cannot be repeated, their toxicity being cumulative. Analyses of the available studies showed that some 80% of patients can be maintained in remission with cyclosporin A (CsA) but relapse occurs when the drug is stopped. Severe side effects are rare. In particular, the mean values of creatinine clearance did not deteriorate in cyclosporin-treated patients and repeat renal biopsy showed only mild changes in some patients. There is no definite treatment for focal glomerulosclerosis. An analysis of 10 clinical trials showed that some 17% of nephrotic patients may enter complete remission of proteinuria and another 13% may attain partial remission of the nephrotic syndrome with CsA. There is concern over the use of this drug since cases of irreversible renal dysfunction have been reported. However, retrospective reviews of the available studies showed that the mean serum creatinine levels did not modify if patients had normal renal function when given CsA. A 6-month course of methylprednisolone and chlorambucil may obtain remission of the nephrotic syndrome in some 60% of patients with membranous nephropathy. Some trials have shown that CsA may improve proteinuria and there is also some suggestion that the drug might protect against renal function deterioration. Thus, when given at correct doses, CsA may exert an anti-proteinuric effect without deteriorating renal function, suggesting that the drug may represent a further tool in treating the primary nephrotic syndrome.

Ciclosporin treatment in children with steroid-dependent nephrotic syndrome

We report our experience with ciclosporin (CS) treatment in 18 children with steroid-dependent nephrotic syndrome. CS was started at 3-5 mg/kg per day after the patients had attained remission with steroid therapy, and was adjusted to maintain a trough blood level of between 250 and 600 ng/ml, being administered for 6 months. Although 1 patient dropped out of the study because of renal dysfunction, the remaining 17 children completed the full trial. No relapse occurred during the 6-month period of CS treatment, and it was possible to discontinue steroid therapy in all patients. However, after discontinuation of CS treatment, nephrotic syndrome relapsed in 16 patients and 14 again had frequent relapses and became steroid-dependent, as before CS treatment. The effect of CS in maintaining remission from steroid-dependent nephrotic syndrome was thus dependent on continuation of CS treatment. Although several side-effects occurred during CS treatment, they were not so serious as to necessitate discontinuation of treatment, except in 1 patient, and all of these side effects were reversible. CS is therefore a new agent for the management of children with steroid-dependent nephrotic syndrome in place of corticosteroid and alkylating agents, although long-term maintenance therapy may be necessary for maintaining longer remission.

Nephrotic syndrome: from toddlers to twenties

63 patients with steroid-sensitive, biopsy-proven minimal-change nephrotic syndrome were followed for between 10 and 21 years. 2 died. All the survivors had normal renal function and blood pressure, and only 2 had a single attack. Frequent relapse was more common with young age of onset and in boys. The frequency of relapse fell rapidly over the first 4 years after diagnosis and then plateaued. Relapses continued into adult life. No definite endpoint to the disease could be defined although there was a linear relation between length of remission and risk of subsequent relapse.

Long-term prognosis for children with nephrotic syndrome

Follow-up survival and health information were obtained, after a median of 27.5 years, from 132 patients who had been seen originally as children with nephrotic syndrome between 1951 and 1967. Ninety seven patients were alive. Recurring edema or proteinuria, or both, persisted in 15 percent of those still alive. Eight of 11 parous women reported relapses during pregnancy. There was no apparent increase in malignancies, atopic diseases, clinical defects in cell-mediated immunity, or cardiovascular diseases. Twenty two patients (17%) died of renal causes between 3 months and 8 years after the onset of nephrotic syndrome. Steroid resistance was the presenting feature universally predictive of a poor outcome; nine of the 11 such patients died and the other two are now receiving hemodialysis. Hematuria was present initially in 41 percent of the patients who died of renal causes, compared with 14 percent of those still alive. Hypertension was noted on the first examination in 22 percent of those who died of renal causes, compared with 10 percent of those alive.

Late resistance to corticosteroids in nephrotic syndrome

Corticosteroid resistance appeared late in the course of relapsing nephrotic syndrome in 12 patients who previously had steroid-sensitive relapses for 0.8 to 13 years. In 11 patients, renal histology performed earlier in the course of the disease showed minimal change in eight, mesangial proliferative glomerulonephritis (MesPGN) in two, and focal segmental glomerulosclerosis (FSGS) in one. Renal biopsy in another patient and a repeat procedure in four of eight patients who initially showed minimal change was done after they had developed steroid resistance, and showed FSGS. Cyclophosphamide was given to 11 patients after they became steroid resistant, and induced remission in eight that continued for 1 to 2 years in two patients. The other six had relapses that were steroid sensitive, but three of them (two with FSGS and one with MesPGN) later became resistant to steroids as well as to cyclophosphamide. Of six patients with FSGS, four with initial or subsequent resistance to cyclophosphamide eventually developed renal insufficiency. The other two have remained in remission for 12 to 16 years; one of these did not receive cyclophosphamide. Our observations suggest that patients with late steroid resistance comprise a heterogeneous group; those with FSGS and resistance to cyclophosphamide therapy may have a poor outcome.

Long-term outcome for children with minimal-change nephrotic syndrome

A retrospective study was undertaken to assess the outcome of a cohort of 183 unselected children who presented with the nephrotic syndrome between 1963 and 1969. All subjects showed minimal glomerular changes in biopsy samples and were given conventional steroid therapy. Information was available on 152 children, now aged 14-32 years. Activity persisted longer in patients presenting at an early age. The outcome for most of the children was favourable. Only 10 patients (5.5%), all of whom presented with initial symptoms before their 6th birthday, continued to have steroid-responsive relapses in adult life. There were 11 deaths, of which 7 (4% of the series) were from avoidable complications of the disorder.

Clinical course and renal function in minimal change nephrotic syndrome

Thirteen unselected children with the minimal change nephrotic syndrome were followed for 11 months-7.5 years, during which time 32 renal function tests were performed. Glomerular filtration rate (GFR) was determined as clearance of inulin using a standard clearance technique. The children had between zero and 34 relapses and three developed steroid resistance. Three patients had severe but reversible complications related to the corticosteroid therapy. Chlorambucil was given to four patients, of whom three with steroid resistance had lasting remissions, whereas one patient with frequent relapses had only transient improvement. The GFR was decreased at the first episode in six patients, whose clinical course did not differ from that of the others. None had a decreased GFR later in the course of the disease. It is concluded that reduced GFR at the onset of the minimal change nephrotic syndrome is reversible and does not imply an unfavourable outcome.

A lymphocytotoxic factor(s) in plasma of patients with minimal change nephrotic syndrome: partial characterization

The incidence, relationship to clinical disease, and physical characteristics of a plasma cytotoxic factor(s) were studied in steroid-responsive minimal change nephrotic syndrome (MCNS) and other renal diseases. Plasma activity was found in 76% of 67 children with MCNS and in 67% of 9 children with focal segmental sclerosis (FSS). Of 31 normal adults and children and 7 adults with membranous glomerulonephritis, only 1 individual had toxic plasma. In MCNS, degree of plasma activity was not related to clinical disease, prednisone dosage, or serum levels of IgG or alpha-2-macroglobulin. The active factor(s) was found more frequently in plasma than in serum, was heat stable and nondialyzable by selected filtration, and was approximately 100,000 to 300,000 molecular weight. By DEAE column chromatography, activity coincided with fractions containing IgA and IgM but not IgG. While the nature of the plasma factor(s) has not been identified, these data indicate that MCNS plasma may adversely affect lymphocyte viability by a slow process of cytotoxicity requiring 24 or more hr, and that such plasma activity occurs frequently in children with MCNS and also with the more severe FSS.

Long-term evaluation of chlorambucil plus prednisone in the idiopathic nephrotic syndrome of childhood

We evaluated the long-term effects of a five to 15-week course of chlorambucil and prednisone in 59 children with idiopathic nephrotic syndrome who had previously received prednisone alone and had had frequent relapses or steroid dependency or resistance. By actuarial analysis of 65 courses of dual therapy followed up for one to 12 years (mean, 5.0), we found that 95 per cent of patients were in remission at one year and 85 per cent at four years. All but two had remissions lasting longer than those induced by steroids alone, and only eight others had one or more relapses after therapy. Life-table analysis of two dosage schedules of chlorambucil at four years showed that 91 per cent of patients on low doses and 80 per cent of those on high doses were still in remission. Although immediate complications were minimal, the potential for long-term toxicity still requires careful selection of patients who receive chlorambucil. Prolonged use of chlorambucil in daily doses above 0.3 mg per kilogram of body weight per day or cumulative doses above 14 mg per kilogram is no longer warranted. Measured in terms of both the immediate and long-term responses, chlorambucil appears to lower the frequency of relapses in idiopathic nephrotic syndrome.

Childhood nephrotic syndrome: clinical associations and response to therapy

The concept of nephrotic syndrome has changed from that of a single disease entity in children to that of a complex association of distinct types of glomerular histopathology and clinical courses. Nephrotic syndrome is steroid-responsive in the majority of children. The prognosis for steroid-responsive children is good, even for those who have frequent relapses requiring maintenance therapy or for those who become steroid-dependent. The disease rarely progresses to renal insufficiency or death in these patients. Cyclophosphamide and chlorambucil have proved effective only in steroid-responsive patients with minimal-lesion disease. Because of their toxicity, these agents should be limited to use in patients with severe steroid side effects. The effectiveness of these drugs in steroid-resistant diseases is unclear and still under investigation.

Chlorambucil dosage in frequently relapsing nephrotic syndrome: a controlled clinical trial

A controlled clinical trial was performed using two dosage regimens of chlorambucil to treat children with frequently relapsing nephrotic syndrome. All children concurrently received prednisone (60 mg/m2 on alternate days). Ten children (Group I) were given chlorambucil as a stable dose (0.2 mg/kg/day) for 56 to 60 days, and 11 children (Group II) received increasing doses (0.2 to 0.63 mg/kg/day) for 42 to 77 days. Two children in each group subsequently relapsed. Follow-up averaged 28.6 and 27.2 months in Groups I and II, respectively. Three children in Group II developed infectious complications. The data indicate that a stable dosage regimen for chlorambucil is as effective as an increasing dose regimen in achieving long-term remission of frequently relapsing nephrotic syndrome.

Chlorambucil treatment of frequently relapsing nephrotic syndrome

Chlorambucil, in combination with prednisone, was compared with prednisone alone in a randomized controlled trial in 21 children with either steroid-dependent or frequently relapsing nephrotic syndrome to assess its effect on the duration of remission and the rate of relapse. All control patients treated with prednisone alone continued to relapse at the same rate, with all patients experiencing a return of proteinuria by seven months. Conversely, those who received the same prednisone therapy along with chlorambucil for six to 12 weeks remained in complete remission, without further medication, during 12 to 34 months of follow-up observation. Complications were minimal. Immediate side effects commonly reported with cyclophosphamide were not seen with chlorambucil. Comparison with published reports also suggests that remission induced by chlorambucil is more stable than that after cyclophosphamide. Chlorambucil appears to be of value in the frequently relapsing nephrotic patient, adding an effect that is unattainable with prednisone alone.

Late nonresponsiveness to steroids in children with the nephrotic syndrome

Among 195 nephrotic children, ten developed resistance to prednisone therapy after responding to this drug on one or more occasions (late nonresponders). All were found to have "minimal lesions" on renal biopsy. Nine of these patients went into remission: one responded to further prednisone therapy, one went into remission while receiving azathioprine, and the remaining seven children responded to cyclophosphamide. Five of these seven patients subsequently relapsed; three of them have continued to respond to prednisone. The other two eventually became steroid resistant a second time, but in both instances a second course of cyclophosphamide again induced a remission. These nine patients have been followed for periods ranging from 6 months to 9.5 years (median = 53 months); all are doing well and have normal renal function. The tenth patient died from sepsis four months after the onset of steroid resistance.