Nephrotic syndrome

Answer 1

Definition

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, high triglyceride levels, and swelling.

Alternative Names

Nephrosis

Causes, incidence, and risk factors

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 (such as strep throat, hepatitis, or mononucleosis), 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.

Symptoms

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
• Weight gain (unintentional) from fluid retention
• Poor appetite
• High blood pressure

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:

• Creatine - blood test
• Blood urea nitrogen (BUN)
• Creatinine clearance
• Albumin blood test - may be low
• Urinalysis - reveals large amounts of urine protein

Fats are often also present in the urine. Blood cholesterol and triglyceride levels may increase.

Kidney biopsymay be needed .

Tests to rule out various causes may include the following:

• Glucose tolerance test
• Antinuclear antibody
• Rheumatoid factor
• Cryoglobulins
• Complement levels
• Hepatitis B and C antibodies
• VDRL serology
• Serum protein electrophoresis

This disease may also alter the results of the following tests:

• Urinary casts
• Protein electrophoresis - urine
• Serum iron

Treatment

The goals of treatment are to relieve symptoms, prevent complications and delay progressive kidney damage. Treatment of the disorder that causes the condition is necessary to control nephrotic syndrome. Treatment may be needed for life.

Controlling blood pressure is the most important measure to delay kidney damage. The goal is to keep blood pressure at or below 130/80 mmHg. Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are the medicines most often used in this case. ACE inhibitors may also help decrease the amount of protein loss in the urine.

Corticosteroids and other drugs that suppress or quiet the immune system may be used.

High cholesterol and levels should be treated to reduce the risk of heart and blood vessel problems. However, a low-fat, low-cholesterol diet is usually not as helpful for people with nephrotic syndrome. Medications to reduce cholesterol and triglycerides may be needed, most commonly statins.

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 or may not be helpful. A moderate-protein diet (1 gram of protein per kilogram of body weight per day) may be suggested.

Vitamin D may need to be replaced if nephrotic syndrome is chronic and unresponsive to therapy.

Blood thinners may be required to treat or prevent clot formation.

Expectations (prognosis)

The outcome varies; the syndrome may be acute and short-term or chronic and unresponsive to therapy. The cause and development of complications also affects the outcome.

Complications

• Atherosclerosisand related heart diseases
• Renal vein thrombosis
• Acute kidney failure
• Chronic kidney disease
• Infections, including pneumococcal pneumonia
• Malnutrition
• Fluid overload, congestive heart failure, pulmonary edema

Calling your health care provider

Call your health care provider if symptoms which may indicate nephrotic syndrome occur.

Call your health care provider if nephrotic syndrome persists or if new symptoms develop, including severe headache, fever, sores on the skin, cough, discomfort with urination, or decreased urine output.

Go to the emergency room or call the local emergency number (such as 911) if convulsions occur.

Prevention

Appropriate treatment of conditions that can cause nephrotic syndrome may help prevent the syndrome.

References

In: Brenner BM, ed. Brenner: Brenner and Rector's the Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 30.

Answer 2

Definition

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.

Alternative Names

Nephrosis

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:

• Cancer
• 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
• Glomerulonephritis
• 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.

Symptoms

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
• Urinalysis

Fats are often also present in the urine. Blood cholesterol and triglyceride levels may be high.

A kidney biopsymay be needed to find the cause of the disorder.

Tests to rule out various causes may include the following:

• Antinuclear antibody
• Cryoglobulins
• 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

Treatment

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.

Treatments:

• 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.

Expectations (prognosis)

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.

Complications

• Acute kidney failure
• Atherosclerosisand related heart diseases
• Chronic kidney disease
• Fluid overload, congestive heart failure, pulmonary edema
• Infections, including pneumococcal pneumonia
• Malnutrition
• 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:
  • Cough
  • Decreased urine output
  • Discomfort with urination
  • Fever
  • Severe headache
  • Sores on the skin

Go to the emergency room or call the local emergency number (such as 911) if you have convulsions.

Prevention

Treating conditions that can cause nephrotic syndrome may help prevent the syndrome.

References

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.

Reviewed By

Review Date: 09/20/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Herbert Y. Lin, MD, PhD, Nephrologist, Massachusetts General Hospital, Associate Professor of Medicine, Harvard Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.