Nephrotic syndrome

What it is

Nephrotic syndrome is proteinuria greater than 3.5 g per 24 hr with hypoalbuminemia and edema, and it results from damage to the podocytes, which is structural damage of the glomerular filtration barrier with massive renal loss of protein. It is one of the two clinical manifestations of glomerular disease, the other being nephritic syndrome. Some diseases that manifest with nephritic syndrome can at the same time cause nephrotic-range proteinuria greater than 3.5 g/day, and when the criteria for both syndromes are fulfilled the findings are called mixed nephritic-nephrotic syndrome. Classifying a presentation as nephritic, nephrotic or mixed narrows the list of likely differential diagnoses.

The four classic features are gathered as PEAL: proteinuria above 3.5 g/day, edema, hypo-albuminemia and hyperlipidemia. Written as diagnostic criteria they are heavy proteinuria greater than 3.5 g/24hrs, hypoalbuminemia and edema, with hyperlipidemia, that is an elevated LDL cholesterol, and lipiduria, that is fatty casts and oval fat bodies on microscopy, as the fourth that may or may not be there.