What is Nephrotic Syndrome ?
What is Nephrology Syndrome ?
Nephrotic syndrome is a nonspecific kidney disorder characterized by a number of signs of disease: proteinuria, hypoalbuminemia and edema.It is characterized by an increase in permeability of the capillary walls of the glomerulus leading to the presence of high levels of protein passing from the blood into the urine (proteinuria at least 3.5 grams per day per 1.73m2 body surface area)( > 40 mg per square meter body surface area per hour ) low levels of protein in the blood (hypoproteinemia or hypoalbuminemia), ascites and in some cases, edema; high cholesterol (hyperlipidaemia or hyperlipemia) and a predisposition for coagulation.
Signs and symptoms
It is characterized by proteinuria (>3.5g/day), hypoalbuminemia, hyperlipidaemia, and edema (which is generalized and also known as anasarca or dropsy) that begins in the face. Lipiduria (lipids in urine) can also occur, but is not essential for the diagnosis of nephrotic syndrome. Hyponatremia also occurs with a low fractional sodium excretion.
Hyperlipidaemia is caused by two factors:
Hypoproteinemia stimulates protein synthesis in the liver, resulting in the overproduction of lipoproteins.
Lipid catabolism is decreased due to lower levels of lipoprotein lipase, the main enzyme involved in lipoprotein breakdown.Cofactors, such as Apolipoprotein C2 may also be lost by increased filtration of proteins.
Pathophysiology
The renal glomerulus filters the blood that arrives at the kidney. It is formed of capillaries with small pores that allow small molecules to pass through that have a molecular weight of less than 40,000 Daltons,but not larger macromolecules such as proteins.
In nephrotic syndrome, the glomeruli are affected by an inflammation or a hyalinization (the formation of a homogenous crystalline material within cells) that allows proteins such as albumin, antithrombin or the immunoglobulins to pass through the cell membrane and appear in urine.