Severe reversible acute renal failure in idiopathic nephrotic syndrome

Background: Only few cases of acute renal failure (ARF) requiring dialysis have been reported in patients with idiopathic nephrotic syndrome (NS). This study aims to better define the clinical outcome and treatment of this condition. Methods: A pilot enquiry regarding the occurrence of ARF requiring dialysis in patients with NS and biopsy proven minimal changes (MC) or focal segmental glomerulosclerosis (FSGS) was conducted among 5 nephrology centers. Results: From 1996-2006, 6 patients with idiopathic NS (4 MC, 2 FSGS) developed ARF requiring dialysis early after onset of NS. At presentation all but 1 patient had elevated blood pressure. Patients were treated with dialysis from 7-40 days. All achieved complete or partial remission after 4-8 weeks of steroids. Recovery of renal function paralleled with the reduction of proteinuria. At renal biopsy proximal tubules showed a large amount of protein droplets, flattening of epithelial cells, and focal detachment of cells from the basal membrane. After a follow-up of 24-60 months, 5 patients had a relapse. Of these 4 were responsive to steroids, while one progressed to dialysis after an episode of hemolytic uremic syndrome related to cyclosporine treatment. ARF did not recur. Conclusion: ARF requiring dialysis is a rare and unexpected complication of idiopathic NS occurring in most cases early after presentation. These patients are sensitive to steroids that should be administered as promptly as possible in view of the potential noxious effect of protein overload on proximal tubular cells.