What is the main pathophysiological change in nephrotic syndrome?

In nephrotic syndrome, the primary pathophysiological change is increased glomerular permeability. This condition is characterized by a defect in the glomerular filtration barrier, which leads to excessive protein loss in the urine, specifically albumin.

The increased permeability is often due to damage to the podocytes or the glomerular basement membrane, resulting in a loss of the normal ability of the glomeruli to restrict protein from passing into the urine. This heightened permeability allows proteins, primarily albumin, to leak out of the blood and into the urine, leading to the hallmark signs of nephrotic syndrome, such as significant proteinuria, hypoalbuminemia, and edema.

Other options, while related to kidney function, do not represent the primary pathophysiological change. For example, decreased glomerular filtration rate may occur as a consequence of nephrotic syndrome due to alterations in intraglomerular pressure or volume overload. Decreased blood pressure typically does not occur in nephrotic syndrome; in fact, patients may experience hypertension. Increased protein synthesis is not a characteristic of nephrotic syndrome either; rather, the body responds to the loss of protein in the urine, but this does not lead to overall increased protein synthesis