What factors contribute to edema in nephrotic syndrome?

Edema in nephrotic syndrome primarily results from hypoalbuminemia and sodium retention. In nephrotic syndrome, the glomerular filtration barrier is damaged, leading to the excessive loss of proteins, particularly albumin, in the urine. This loss causes hypoalbuminemia, which decreases the oncotic pressure in the blood vessels. As a result, fluid moves from the vascular space into the interstitial tissue, causing swelling or edema.

Additionally, the low albumin levels trigger compensatory mechanisms in the body. The kidneys respond by promoting sodium retention, which helps to maintain blood volume but also contributes to further fluid accumulation in the tissues. This combination of reduced oncotic pressure due to hypoalbuminemia and increased sodium retention explains the significant edema observed in individuals with nephrotic syndrome.

Other options do not accurately represent the pathophysiological processes occurring in nephrotic syndrome or may attribute conditions that are not relevant to this syndrome. For example, hyperalbuminemia would actually contribute to maintaining oncotic pressure, rather than decreasing it.