Nephrotic syndrome is a group of symptoms that include protein in the urine, low blood protein levels, high cholesterol levels, high triglyceride levels, and swelling.
Causes, incidence, and risk factors
Nephrotic syndrome is caused by different disorders that damage the kidneys. This damage leads to the release of too much protein in the urine.
The most common cause in children is minimal change disease. Membranous glomerulonephritis is the most common cause in adults.
This condition can also occur from:
- Diseases such as diabetes, systemic lupus erythematosus, multiple myeloma, and amyloidosis
- Genetic disorders
- Immune disorders
- Infections (such as strep throat, hepatitis, or mononucleosis)
- Use of certain drugs
It can occur with kidney disorders such as:
- Focal and segmental glomerulosclerosis
- Mesangiocapillary glomerulonephritis
Nephrotic syndrome can affect all age groups. In children, it is most common between ages 2 and 6. This disorder occurs slightly more often in males than females.
Swelling (edema) is the most common symptom. It may occur:
- In the face and around the eyes (facial swelling)
- In the arms and legs, especially in the feet and ankles
- In the belly area (swollen abdomen)
Other symptoms include:
- Foamy appearance of the urine
- Poor appetite
- Weight gain (unintentional) from fluid retention
Signs and tests
The doctor will perform a physical exam. Laboratory tests will be done to see how well the kidneys are working. They include:
- Albumin blood test
- Blood chemistry tests such as basic metabolic panel or comprehensive metabolic panel
- Blood urea nitrogen (BUN)
- Creatinine - blood test
- Creatinine clearance - urine test
Fats are often also present in the urine. Blood cholesterol and triglyceride levels may be high.
A kidney biopsy may be needed to find the cause of the disorder.
Tests to rule out various causes may include the following:
- Antinuclear antibody
- Complement levels
- Glucose tolerance test
- Hepatitis B and C antibodies
- HIV test
- Rheumatoid factor
- Serum protein electrophoresis (SPEP)
- Syphilis serology
- Urine protein electrophoresis (UPEP)
This disease may also change the results of the following tests:
- Vitamin D level
- Serum iron
- Urinary casts
The goals of treatment are to relieve symptoms, prevent complications, and delay kidney damage. To control nephrotic syndrome, you must treat the disorder that is causing it. You may need treatment for life.
- Keep blood pressure at or below 130/80 mmHg to delay kidney damage. Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are the medicines most often used. ACE inhibitors may also help decrease the amount of protein lost in the urine.
- You may take corticosteroids and other drugs that suppress or quiet the immune system.
- Treat high cholesterol to reduce the risk of heart and blood vessel problems. A low-fat, low-cholesterol diet is usually not very helpful for people with nephrotic syndrome. Medications to reduce cholesterol and triglycerides (usually statins) may be needed.
- A low-salt diet may help with swelling in the hands and legs. Water pills (diuretics) may also help with this problem.
- Low-protein diets may be helpful. Your health care provider may suggest eating a moderate-protein diet (1 gram of protein per kilogram of body weight per day).
- You may need vitamin D supplements if nephrotic syndrome is long-term and not responding to treatment.
- Blood thinners may be needed to treat or prevent blood clots.
The outcome varies. The condition may be acute and short-term or chronic and not respond to treatment. The complications that occur can also affect the outcome.
Some people may eventually need dialysis and a kidney transplant.
- Acute kidney failure
- Atherosclerosis and related heart diseases
- Chronic kidney disease
- Fluid overload, congestive heart failure, pulmonary edema
- Infections, including pneumococcal pneumonia
- Renal vein thrombosis
Calling your health care provider
Call your health care provider if:
- You have symptoms of nephrotic syndrome
- Nephrotic syndrome does not go away
- New symptoms develop, including:
- Decreased urine output
- Discomfort with urination
- Severe headache
- Sores on the skin
Go to the emergency room or call the local emergency number (such as 911) if you have convulsions.
Treating conditions that can cause nephrotic syndrome may help prevent the syndrome.
Appel GB. Glomerular disorders and nephrotic syndromes. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 122.
Nachman PH, Jennette JC, Falk RJ. Primary glomerular disease. In: Brenner BM, ed. Brenner and Rector's The Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 30.