What Is Nephrotic Syndrome?
Nephrotic syndrome is a collection of symptoms that indicate kidney damage. Nephrotic syndrome includes the following:
- Albuminuria—large amounts of protein in the urine
- hyperlipidemia—higher than normal fat and cholesterol levels in the blood
- edema, or swelling, usually in the legs, feet, or ankles and less often in the hands or face
- hypoalbuminia—low levels of albumin in the blood
Albumin is a protein that acts like a sponge, drawing extra fluid from the body into the bloodstream where it remains until removed by the kidneys. When albumin leaks into the urine, the blood loses its capacity to absorb extra fluid from the body, causing edema.
Nephrotic syndrome results from a problem with the kidneys’ filters, called glomeruli. Glomeruli are tiny blood vessels in the kidneys that remove wastes and excess fluids from the blood and send them to the bladder as urine.
As blood passes through healthy kidneys, the glomeruli filter out the waste products and allow the blood to retain cells and proteins the body needs. However, proteins from the blood, such as albumin, can leak into the urine when the glomeruli are damaged. In nephrotic syndrome, damaged glomeruli allow 3 grams or more of protein to leak into the urine when measured over a 24-hour period, which is more than 20 times the amount that healthy glomeruli allow.
Source: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)