Renal tubular dysfunction complicating the nephrotic syndrome

Observations on two girls in whom an unusual type of chronic renal insufficiency developed many months after the onset of nephrotic syndrome are reported. Each patient became free of edema in spite of persistent massive proteinuria. Growth was retarded and rickets and attacks of tetany developed. The chemical disturbances of the blood were characterized by hypocalcemia, hypokalemia, azotemia and metabolic acidosis. Hyposthenuria, proteinuria, amino-aciduria, and minimal erythrocyturia, cylindruria and glycosuria were present. Healing of the rickets and cessation of attacks of tetany followed the administration of vitamin D and calcium salts. Prednisone was administered to one patient and thereafter proteinuria decreased and renal tubular function improved. Both girls are relatively asymptomatic 11 and 9 years after the onset of nephrotic syndrome, although they are rather small and still have evidence of renal disease. It is possible that cells of the renal tubules have been damaged as a result of prolonged massive proteinuria.