Definition

Nephrotic syndrome is the kidneys leaking protein into the urine. When this happens, there is not enough protein in the blood. Low protein in the blood allows fluid to leak out of the blood stream and into body tissues.

Nephrotic syndrome is a collection of the following signs:

• High protein in the urine
• Low protein in the blood
• Swelling of body tissues
• High cholesterol in the blood

Nephrotic syndrome is not a disease itself. It is a set of signs and symptoms that indicate that another disease has damaged the kidneys, and that they are no longer working properly.

Causes

Nephrotic syndrome is caused by damage to tiny filters in the kidneys, called glomeruli. The glomeruli filter waste and excess water from the blood. This forms urine, which reaches the bladder via the ureters. Diseases that damage the glomeruli cause nephrotic syndrome.

Diseases that may lead to nephrotic syndrome include:

• Glomerulonephritis—inflammation of the glomeruli from infection or other causes
• Diabetic nephropathy—kidney complications from diabetes
• Membranous nephropathy
• IgA nephropathy
• Membranoproliferative glomerulonephritis
• Renal amyloidosis—abnormal protein deposits in the kidneys
• Minimal change disease
• Other diseases, including systemic lupus erythematosus, certain infections, toxins, drugs, allergic reactions, sickle cell disease, renal vein thrombosis, and some types of cancer

Risk Factors

Factors that may increase your chance of nephrotic syndrome include:

• Diabetes
• Systemic lupus erythematosus
• Exposure to drugs or toxins
• Certain infections

Symptoms

Nephrotic syndrome may cause:

• Swelling around the following body parts:
  • Feet
  • Ankles
  • Abdomen
  • Hands
  • Face
  • Eyes
• Weight gain from excess fluids
• Shortness of breath
• Poor appetite
• Foamy urine
• Fatigue

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. High blood pressure may indicate kidney damage. A urine test will show if you have too much protein or any blood

in your urine. A blood test will show if your blood contains too much cholesterol and not enough protein.

Tests may include:

• Blood tests
• Urine tests
• Biopsy

Imaging studies evaluate the kidney and surrounding structures. This can be done with:

• CT scan
• MRI scan
• Ultrasound

If your doctor suspects nephrotic syndrome, you may be referred to a kidney specialist.

Treatment

Treatment depends on what is causing the nephrotic syndrome. Some cases are treatable with medications, while others lead to kidney failure despite treatment. The underlying cause will be treated, if possible. Steps will be taken to:

• Adjust your diet to replace protein lost in the urine
• Use ACE inhibitors to reduce protein loss in some cases
• Treat edema by restricting salt intake and taking diuretics
• Lower cholesterol and blood pressure with diet, exercise, and medications

Prevention

Most conditions that lead to nephrotic syndrome cannot be prevented. However, the risk of type 2 diabetes may be reduced through exercise and weight control.

National Kidney Foundation http://www.kidney.org

Kidney Foundation of Canada http://www.kidney.ca

Nephrotic syndrome in adults. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated November 28, 2012. Accessed July 12, 2013.

Nephrotic syndrome in adults. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at:
http://www.niddk.nih.gov/health-information/health-topics/kidney-disease/nephrotic-syndrome-in-adults/Pages/facts.aspx
Updated April 19, 2012. Accessed July 12, 2013.