ABSTRACT
Nephrotic Syndrome Nephrotic syndrome is defined as the presence of urinary protein greater than 3.5 g/1.73 m2 per 24 hours, hypoalbuminemia (<3.0 g/dL), peripheral edema, hypercholesterolemia, and lipiduria. Edema can be prominent. Children usually manifest matinal periorbital edema that resolves during the day as the child stands upright. Severe hyperlipidemia can result in the development of xanthelasma. Urinalysis shows waxy casts, free fat, oval fat bodies, and lipiduria (“Maltese crosses”). Complications of nephrotic syndrome include hypogammaglobulinemia (which increases infection risk, especially cellulitis and spontaneous peritonitis), vitamin D deficiency due to loss of vitamin D-binding protein, and iron deficiency anemia due to hypotransferrinemia. Thrombotic complications are common (eg, renal vein thrombosis) and occur because of increased levels of prothrombotic factors (increased factor V, VIII, fibrinogen, and platelets and decreased antithrombin III and antiplasmin). Patients at increased risk include those with proteinuria greater than 10 g/1.73 m2 per 24 hours and a serum albumin level less than 2 g/dL. Symptoms of renal vein thrombosis include flank pain and hematuria. In cases of bilateral renal vein thrombosis, patients may present with acute renal failure. Apart from renal vein thrombosis, in patients with nephrotic syndrome acute renal failure may develop from several mechanisms (eg, prerenal volume depletion, sepsis, interstitial nephritis, and drugs such as angiotensin-converting enzyme inhibitors [ACEIs] and nonsteroidal anti-inflammatory drugs [NSAIDs]). Management of nephrotic syndrome includes using diuretics, controlling blood pressure (ACEIs and angiotensin receptor blockers [ARBs] are preferred), and limiting the intake of protein (0.8 g/kg per day) and sodium (<4 g per day), and controlling lipid levels (with the use of HMG-CoA reductase inhibitors). Anticoagulation should be considered for patients at increased risk, (proteinuria >10g in 24 hours and serum albumin <2 g/dL), especially if the nephrotic syndrome is due to membranous nephropathy or amyloidosis.
