What characteristics define nephrotic syndrome?

Nephrotic syndrome is characterized by a specific set of features that arise due to glomerular damage, leading to significant alterations in kidney function and protein handling. The defining characteristics include:

1. Proteinuria: This is a hallmark of nephrotic syndrome, typically quantitated as more than 3.5 grams of protein lost in the urine per day. This occurs due to a disruption in the glomerular filtration barrier, allowing proteins, primarily albumin, to leak into the urine.

2. Hypoalbuminemia: As a consequence of significant protein loss through the urine, serum albumin levels decrease. This drop in albumin often results in lower oncotic pressure in the blood, potentially leading to edema due to fluid shifting from the intravascular space to the interstitial space.

3. Hyperlipidemia: In response to low albumin levels, the liver increases the production of lipoproteins, resulting in elevated cholesterol and triglycerides in the blood. This is part of the body's compensatory response to the perceived state of protein deficiency.

4. Edema: The combination of hypoalbuminemia and increased capillary permeability leads to the accumulation of fluid in tissues, manifesting