Nephrotic syndrome (NS) is the most basic features of proteinuria, hypoalbuminemia, edema (height) and hyperlipidemia, the so-called "three high and one low", and other metabolic disorders characterized by a group of clinical syndrome.
1 large amounts of proteinuria
A large number of proteinuria is the most important clinical manifestations of NS patients, and is also the most basic pathological and physiological mechanism of nephrotic syndrome. A large number of protein urine is refers to the adult urinary protein excretion >3.5g/d. Under normal physiological conditions, glomerular filtration membrane has a molecular barrier and a charge barrier, resulting in an increase in the amount of protein in the original urine, and a large amount of proteinuria is formed when the volume of the membrane is much more than the proximal tubule. On the basis of the above, it can increase the excretion of urinary protein by increasing the pressure in the glomerular and leading to high perfusion and high filtration (such as high blood pressure, high protein diet, or a large amount of plasma protein).
2 low serum albumin
Plasma albumin fell to <30g/L. NS when a large number of albumin lost from the urine, promote the albumin liver compensatory synthesis and the increase of renal tubular decomposition. When liver albumin synthesis is not sufficient to overcome the loss and decomposition, then the emergence of low serum albumin. In addition, NS patients due to gastrointestinal mucosal edema leading to poor appetite, insufficient protein intake, malabsorption or loss, also aggravate hypoproteinemia.
NS time of low albumin, plasma colloid osmotic pressure drop, so that water from the vascular cavity into the tissue gap, is the basic cause of NS edema. Recent studies show that the normal or decreased blood volume of about 50% patients, normal or decreased plasma renin levels, suggesting that some of the primary in the renal sodium, water retention factors in the mechanism of NS edema play a role.
The cause of NS complicated with hyperlipidemia has not been fully clarified at present. High cholesterol and (or) high triglyceride, serum LDL, VLDL and lipoprotein (a) concentration increased, often with the coexistence of low protein. High cholesterol is mainly due to the increase in the liver synthesis lipoprotein, but also played a part in the reduction of the decomposition of the surrounding cycle. High triglyceride is mainly due to the breakdown of metabolic disorders, liver synthesis is a minor factor.