Minimal Change Disease, Mesangial Proliferative Glomerulonephritis and Focal Sclerosis: Individual Entities or a Spectrum of Disease? In: Robinson RR, Dennis VW, Ferris TF, Glassock RJ, Kokko JP, Tisher CC, editors. Nephrology. New York: Springer; 1984. pp. 634-44. [DOI: 10.1007/978-1-4612-5284-9_58]

Adult-onset idiopathic nephrotic syndrome associated with pure diffuse mesangial hypercellularity

BACKGROUND

Pure diffuse mesangial hypercellularity (DMH), in its primary form, is a relatively rare histological finding and few data exist in the literature regarding its clinical course and prognosis in nephrotic adults with this diagnosis.

METHODS

We retrospectively analysed the clinical and histological data of 28 adult nephrotic patients (13 male) with this diagnosis with regard to response to the treatment, outcome and prognostic indicators.

RESULTS

Of 25 patients treated with prednisolone (Pred), nine (36%) showed complete remission (CR) of proteinuria, eight (32%) partial remission (PR) and eight (32%) did not respond at all (NR). The combination of cyclosporin treatment with prednisolone of those with PR or NR produced one further complete and two partial remissions. At the end of follow-up (mean 64 months), 10 patients (40%) were in CR, nine (36%) in PR and six (24%) were NR and remained nephrotic. Renal function remained unchanged in patients with CR or PR. In contrast, the six non-responders progressed to end-stage renal disease (ESRD). Compared with non-responders, patients who responded to Pred were older and had normal renal function at presentation. This group also had less mesangial sclerosis and severe tubulointerstitial fibrosis and none showed synechiae with Bowman's capsule. IgM mesangial deposits were observed in 22% of patients with CR in response to Pred, in 37% of those with PR and in 100% of non-responders, who finally progressed to ESRD. A multivariate analysis of clinical and histological features at biopsy showed persistent nephrotic syndrome (P<0.001), the severity of DMH (P<0.03) and the presence of mesangial IgM (P<0. 01) to have independent predictive value for ESRD. This analysis also demonstrated that only mesangial sclerosis (P<0.03) and the presence of mesangial IgM (P<0.002) independently predicted the response to therapy.

CONCLUSIONS

DMH associated with idiopathic nephrotic syndrome is a heterogeneous entity. Patients who respond to therapy (completely or partially) have a benign course similar to that of minimal change nephrotic syndrome. They are usually older and have normal renal function at presentation, whereas 'sclerotic' lesions are less frequent findings in initial biopsies. Non-responders tend to be younger and progress to ESRD. Most of them have impaired renal function at first assessment and more prominent 'sclerotic' lesions on initial biopsies. Mesangial IgM is an independent marker of poorer response to treatment and progression to ESRD but it lacks specificity.

Glomerular volume and renal function in children with different types of the nephrotic syndrome

Glomerular hypertrophy has been suggested to be an important factor in the pathogenesis of focal glomerular sclerosis. The aim of the present study was to analyse retrospectively the renal biopsies of 58 children (0.2-16.1 years of age) with different types of the nephrotic syndrome, minimal change nephrotic syndrome (MCNS), diffuse mesangial proliferation (DMP) and focal segmental glomerulosclerosis (FSGS). Glomerular surface area was measured and glomerular volume was calculated and related to steroid responsiveness and to renal function, measured by clearances of inulin and para-aminohippuric acid. Glomerular volume correlated with body surface area (BSA) and age. Because of this, patients with FSGS and DMP were matched according to BSA and age, with corresponding MCNS patients. Glomerular volumes of FSGS and DMP patients were significantly larger than those of MCNS patients. In the MCNS patients, significant correlations were found between glomerular volumes and glomerular filtration rate and effective renal plasma flow. Steroid-dependent and steroid-resistant patients showed larger glomeruli than the steroid-responsive children. We suggest that hyperfiltration and hyperperfusion, among other factors, may contribute to glomerular hypertrophy, mesangial proliferation and glomerulosclerosis.

Cyclosporin A treatment in children with minimal change nephrotic syndrome and focal segmental glomerulosclerosis

In a pilot study 23 children with nephrotic syndrome were treated with cyclosporin A (Cs) for 6-45 months. 8 children suffered from steroid dependent minimal change nephrotic syndrome (MCNS) and had experienced at least one course with cytotoxic drugs, but had relapsed thereafter. 2 children had diabetes mellitus type I with nephrotic syndrome and 13 children had steroid resistant focal segmental glomerulosclerosis (FSGS). Cs was started with 100 mg/m2/day in two doses and increased stepwise to obtain a Cs whole blood trough level of 200-400 ng/ml. In steroid dependent MCNS treatment with Cs reduced relapse rate significantly, and prednisone therapy could be stopped completely. After discontinuation of Cs, relapses reoccurred as frequently as before. Renal function remained unimpaired despite repeated Cs treatment courses up to 38 months. In cases of nephrotic syndrome with diabetes type I Cs treatment led to complete remission without changing the insulin requirement. However, after discontinuation of Cs relapses reoccurred. In steroid resistant FSGS 6 children benefited from Cs treatment: 4 went into complete remission, 2 into partial remission. The 2 children with complete remission relapsed but remained Cs responsive. The remaining 7 children with FSGS did not respond to Cs but continued the course of their disease, with two patients rapidly progressing to terminal renal failure. Side-effects of Cs treatment were mild. It is concluded that Cs is an effective agent in steroid dependent MCNS and can be used as an alternative drug in specific cases like steroid toxicity or diabetes mellitus. In steroid resistant FSGS a trial with Cs seems to be warranted since some cases do respond favorably. To avoid nephrotoxicity treatment with Cs should always be monitored closely by determination of blood levels and renal function.

Immunopathological findings in idiopathic nephrosis: clinical significance of glomerular "immune deposits"

Idiopathic nephrosis (IN), which includes minimal change (MCD), diffuse mesangial proliferation (DMP) and focal segmental glomerular sclerosis (FSGS), is classically characterized by the absence of significant deposits by immunofluorescence microscopy (IF), except for the focal lesions of segmental sclerosis and/or hyalinosis of FSGS, which fix IgM and C3 antiserums. Since IF is available in most centres, an increasing number of unexpected findings has been reported. In order to evaluate the clinical significance of the glomerular deposits revealed by IF in some instances, we reviewed the renal biopsy findings of 222 consecutive children presenting with IN and in whom IF microscopy was available. By light microscopy, 122 patients showed MCD, 10 DMP, and 90 FSGS with DMP (11 cases) or without (79 cases). By IF, 125 specimens were negative and served as controls; 54 showed mesangial IgM deposits, 24 mesangial IgG deposits (associated with Clq deposits in 16), 15 scattered granules of C3 and 4 predominant deposits of mesangial IgA. We correlated these findings with initial response to steroid therapy and outcome and could find no significant difference between the various categories defined by IF and the control group. Repeat biopsies, performed in 21 cases, showed the persistence of deposits in 11 and their transformation in 10. The particular problem raised by the patients who present with IN and mesangial IgA deposits is discussed. Our results demonstrate that patients presenting with IN and "positive IF", whether showing IgM, IgG and Clq, C3 or IgA, do not represent distinct clinicopathological entities.

Primary glomerulonephritis in Hong Kong

The clinical presentation and natural history of 428 patients with biopsy-proven primary glomerulonephritis were reviewed. Minimal change glomerulonephritis presented with the nephrotic syndrome and followed a benign course. Membranous glomerulonephritis took a slow downhill course. HBs antigenaemia was present in 30% of patients with membranous glomerulonephritis. Mesangiocapillary glomerulonephritis often presented with mixed nephritic-nephrotic syndrome and had a bad prognosis. No type II variant was detected. Mesangial IgA glomerulonephritis commonly presented with abnormal urinary sediments although 2.5% of adults presenting with the nephrotic syndrome without glomerular insufficiency had mesangial IgA disease. Mesangial IgA glomerulonephritis was an important cause of end-stage renal failure in Hong Kong.

Cyclosporin in the treatment of idiopathic nephrotic syndrome in children

Thirty-five children (12 girls, 23 boys), aged from 1 year and 5 months to 14 years at the onset of idiopathic nephrotic syndrome, received cyclosporin A (CyA) because of steroid toxicity or failure to respond to steroids. The initial oral dose was 6 mg/kg per day and this was adjusted to obtain trough plasma levels of 50-150 ng/ml. The duration of treatment was between 2 and 8 months. In patients who responded to CyA treatment, the dosage was tapered off; treatment was stopped if found to be ineffective. Of the 35 children, 20 were frequent-relapsing steroid responders who suffered serious side-effects from steroid therapy. Seventeen of them either went into remission or did not relapse despite the withdrawal of prednisone. Prednisone doses could be lowered but not stopped in 1 patient and the remaining 2 patients relapsed when prednisone was tapered off. At the final examination, 10 of the 12 children in whom CyA was tapered off and who had initially responded to CyA had relapsed. A second course was given to these 10 patients and 3 failed to respond. Five children were partial steroid responders and CyA induced a remission in 1 and a partial remission in another. Among the 10 children who were steroid resistant, only 1 responded to CyA, 2 had a partial response and 7 failed to respond to CyA. A reduction of glomerular filtration rate occurred in 8 patients, 7 of whom had either persistent nephrotic syndrome or were in relapse, which suggests that factors other than CyA nephrotoxicity may have been operative. Complete reversal occurred in only 4 patients. Significant histological changes, likely to be related to CyA, were seen in 2 repeat renal biopsies out of the 11 performed.