Pronounced: Neh-frah-tik sin-dromeEn Español (Spanish Version)
Nephrotic syndrome occurs when the kidneys let protein leak into the urine. When this happens, there is too little 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 and symptoms:
- 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 another disease has damaged the kidneys, and they are no longer working properly.
This is a serious condition that requires care from your doctor. Contact your doctor if you think you may have nephrotic syndrome.
Anatomy of the Kidney
© 2008 Nucleus Medical Art, Inc.
Nephrotic syndrome is caused by damage to tiny filters in the kidneys, called glomeruli. The glomeruli filter waste and excess water from the blood forming 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 long-standing diabetes)
- Membranous nephropathy
- Renal amyloidosis (abnormal protein deposits in the kidneys)
- Minimal change disease—This usually occurs in children when nephrotic syndrome occurs, despite little or no change to the structure of glomeruli or surrounding tissue upon examination.
- Other diseases, including systemic lupus erythematosus , certain infections, toxins, allergic reactions, sickle cell disease , renal vein thrombosis, some types of cancer, and other diseases
The following factors increase your chance of developing nephrotic syndrome. If you have any of these risk factors, tell your doctor.
- Kidney disease
Symptoms may include:
Swelling around the following body parts:
- Weight gain from excess fluids
- Shortness of breath
- Poor appetite
- Foamy urine
Your doctor will ask about your symptoms and medical history, and perform a physical exam. High blood pressure may indicate kidney damage. A urine test will show if you have too much protein in your urine, and a blood test will show if your blood contains too much cholesterol and not enough protein.
Other blood tests may be performed to determine the cause of the syndrome and to assess how well the kidney is functioning. If your doctor suspects nephrotic syndrome, he or she may refer you to a nephrologist (kidney specialist).
In some cases, a biopsy of the kidney is necessary to determine the cause of the syndrome and the best way to treat it. Imaging tests of the kidneys may also be useful in selected cases. These include:
- Computed tomography (CT) scan—a type of x-ray that uses a computer to make pictures of structures inside the body
- Magnetic resonance imaging (MRI)—a test that uses magnetic waves to make pictures of structures inside the body
- Ultrasound—a test that uses sound waves to examine structures inside the body
Treatment depends on what is causing the nephrotic syndrome. Some cases are treatable with medication, while others lead to kidney failure despite treatment. Besides directly treating the underlying cause, if possible, steps are taken to:
- Adjust 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 (water pills)
- Lower cholesterol and blood pressure with diet, exercise, and medications
Treatment Options for Selected Underlying Kidney Diseases
Minimal Change Disease
Most cases of nephrotic syndrome in children are caused by minimal change disease. This condition is treated with oral steroids, such as prednisone. If the child does not respond to treatment, the doctor may prescribe other medications. Most children outgrow minimal change disease in their teen years and don’t have any permanent kidney damage.
The most common kidney disease leading to nephrotic syndrome in adults is membranous nephropathy. Treatment for this condition is controversial, though it usually involves medications to suppress the activity of the immune system.
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.
American Kidney Fund
National Kidney Foundation
BC Health Guide
The Kidney Foundation of Canada
Childhood nephrotic syndrome. National Kidney Foundation website. Available at: http://www.kidney.org/news/newsroom/fsitem.cfm?id=19 . Accessed January 13, 2008.
Childhood nephrotic syndrome. National Kidney and Urologic Disease Information Clearinghouse website. Available at: http://kidney.niddk.nih.gov/kudiseases/pubs/childkidneydiseases/nephrotic_syndrom/index.htm . Accessed January 13, 2008.
Kasper DL, et al (eds). Harrison’s Principles of Internal Medicine . 16th ed. New York: McGraw Hill; 2005.
Nephrotic syndrome. Current Medical Diagnosis and Treatment . 44th ed. 2005.
Nephrotic syndrome. EBSCO DynaMed website. Available at: http://dynamed101.ebscohost.com/Detail.aspx?id=114446 . Accessed January 13, 2008.
Nephrotic syndrome. National Kidney Foundation website. Available at: http://www.kidney.org/news/newsroom/fsitem.cfm?id=18 . Accessed January 13, 2008.
Nephrotic syndrome in adults. National Kidney and Urologic Disease Information Clearinghouse website. Available at: http://kidney.niddk.nih.gov/kudiseases/pubs/nephrotic/index.htm . Accessed January 13, 2008.
Last reviewed January 2008 by Adrienne Carmack, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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