Nephrotic syndrome is a group of symptoms including protein in the urine (more than 3.5 grams per day), low blood protein levels, high cholesterol levels, and swelling. The urine may also contain fat, which can be seen under the microscope.
Nephrotic syndrome is caused by various disorders that damage the kidneys, particularly the basement membrane of the glomerulus. This immediately causes abnormal excretion of protein in the urine.
The most common cause in children is minimal change disease, while membranous glomerulonephritis is the most common cause in adults.
This condition can also occur as a result of infection, use of certain drugs, cancer, genetic disorders, immune disorders, or diseases that affect multiple body systems including diabetes, systemic lupus erythematosus, multiple myeloma, and amyloidosis.
It can accompany kidney disorders such as glomerulonephritis, focal and segmental glomerulosclerosis, and mesangiocapillary glomerulonephritis.
Nephrotic syndrome can affect all age groups. In children, it is most common from age 2 to 6. This disorder occurs slightly more often in males than females.