Which of the following is a hallmark of nephrotic syndrome?

• A. Hematuria with RBC casts and hypertension
• B. Edema with hypoalbuminemia only
• C. Heavy proteinuria (>3.5 g/day) with hypoalbuminemia, edema, and hyperlipidemia
• D. Hypocomplementemia with RBC casts

Answer: (C)

Massive protein loss in urine that leads to hypoalbuminemia, along with edema and changes in lipids, is the defining picture of nephrotic syndrome. When the glomerulus becomes overly permeable to proteins, albumin is lost in the urine, dropping blood albumin levels. The reduced oncotic pressure in the blood pulls fluid into the interstitial spaces, causing edema. In response to hypoalbuminemia, the liver upregulates lipoprotein synthesis, leading to hyperlipidemia. Put together, the classic set includes heavy proteinuria, low serum albumin, edema, and high lipid levels. Other findings like hematuria with RBC casts and hypertension point more toward nephritic processes, and hypocomplementemia with RBC casts suggests immune complex–mediated nephritis. Therefore, the description that lists heavy proteinuria with hypoalbuminemia, edema, and hyperlipidemia best captures the hallmark features of nephrotic syndrome.