Nephrotic syndrome

Definition

Nephrotic syndrome is a group of symptoms including protein in the urine (exceeding 3.5 grams per day), low blood protein levels, high cholesterol levels, and swelling (edema). The urine may also contain fat, which is visible under the microscope.

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, drug exposure, malignancy (cancer), hereditary disorders, immune disorders, or diseases that affect multiple body systems including diabetes, systemic lupus erythematosus, multiple myeloma, and amyloidosis. It can accompany kidney disorders, including 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 )
  • general
  • around the eyes
  • in the extremities, especially the feet and ankles
• Swollen abdomen
• Facial swelling
• Foamy appearance of the urine
• Weight gain (unintentional) from fluid retention
• Poor appetite
• High blood pressure

Signs and tests

Physical examination can detect some symptoms. Other symptoms and signs of causative disorders can also be found with examination.

Urinalysis reveals large amounts of urine protein. Fats are often also present in the urine.

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
• Kidney biopsy

• Urinary casts
• Triglyceride
• Protein electrophoresis - urine
• Serum iron
• Cholesterol
• Albumin

Treatment

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

Corticosteroid, immunosuppressive, antihypertensive, and diuretic medications may help control symptoms. Antibiotics may be needed to control infections. Angiotensin converting enzyme (ACE) inhibitors may significantly reduce the degree of protein loss in the urine and are therefore frequently prescribed for treatment of nephrotic syndrome.

If hypertension occurs, it must be treated vigorously. Treatment of high blood cholesterol and triglyceride levels is also recommended to reduce the risk of atherosclerosis. Dietary limitation of cholesterol and saturated fats may be of little benefit, as the high levels which accompany this condition seem to be the result of overproduction by the liver rather than from excessive fat intake. Medications to reduce cholesterol and triglycerides may be recommended.

High-protein diets are of debatable value. In many patients, reducing the amount of protein in the diet produces a decrease in urine protein. In most cases, a moderate-protein diet (1 gram of protein per kilogram of body weight per day) is usually recommended. Sodium (salt) may be restricted to help control swelling. 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

• Atherosclerosis and related heart diseases
• Renal vein thrombosis
• Acute renal failure
• Chronic renal failure
• 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

Treatment of causative disorders may prevent development of nephrotic syndrome.

Illustrations

Male urinary system

Page Content:

Nephrosis ; nephrosis; lipoid nephrosis