Pharmacologic management of adult idiopathic nephrotic syndrome

The pathophysiology, clinical features, complications, and pharmacologic management of adult idiopathic nephrotic syndrome are reviewed. Loss of plasma proteins in the urine is the primary process leading to the nephrotic syndrome, which is characterized by hypoalbuminemia, hyperlipidemia, and edema. The four principal causes, or subclasses, of adult idiopathic nephrotic syndrome are membranous nephropathy (MN), minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), and membranoproliferative glomerulonephritis (MPGN); definitive diagnosis requires histologic examination of a renal biopsy specimen. Treatment of nephrotic syndrome may be directed at the specific cause of the proteinuria, the proteinuria itself, or the complications induced by the syndrome. The four subclasses of nephrotic syndrome vary in their response to therapy. Corticosteroids, alone or in combination with cytotoxic agents, and cyclosporine have been used to induce partial or complete remission in patients with MN, MCD, and FSGS; combinations of corticosteroids, cytotoxic agents, platelet inhibitors, and anticoagulants have been used to treat patients with MPGN. Treatment of proteinuria involves dietary protein restriction with the possible addition of an angiotensin-converting-enzyme inhibitor or a nonsteroidal anti-inflammatory drug. Management of the complications of nephrotic syndrome encompasses the use of diuretics; a low-cholesterol, low-fat diet; lipid-lowering agents; and anticoagulants. Patients with nephrotic syndrome are in a constant state of flux with respect to fluid status, organ function, and critical protein balance. Treatment is based on the histologic subclass of the disease.