Educational feature on focal segmental glomerulosclerosis (FSGS): an introduction

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.

Evaluation and management of steroid-unresponsive nephrotic syndrome

PURPOSE OF REVIEW

Idiopathic nephrotic syndrome in children is commonly associated with minimal change disease and response to steroid therapy. Steroid-unresponsive nephrotic syndrome is often characterized by persistent proteinuria and progression to chronic kidney disease. Focal segmental glomerulosclerosis is the leading cause of steroid-unresponsive nephrotic syndrome in childhood. There is no uniformed consensus as to the treatment of steroid-unresponsive nephrotic syndrome. Advances in the pathogenesis, genetics and biomarkers or surrogate markers may be useful for the diagnosis and identification of patients with steroid-unresponsive nephrotic syndrome, severity of disease, progression and response to therapy.

RECENT FINDINGS

This review is intended to describe some of the recent changes in the epidemiology of steroid-unresponsive nephrotic syndrome, in particular focal segmental glomerulosclerosis, its pathogenesis and alternative therapies.

SUMMARY

Recent studies in both children and adults have shown an increase in the incidence of focal segmental sclerosis as a cause of steroid-unresponsive nephrotic syndrome. Advances in the pathogenesis and noninvasive methods of diagnosis may allow for the identification of steroid-responsive patients.