A constellation of signs and symptoms including protein in the urine (exceeding 3.5 grams/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 which damage the kidneys, particularly to 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 , 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. Males are slightly more likely to be affected than females.
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:
glucose tolerance testantinuclear antibodyrheumatoid factorcryoglobulinscomplement levelsHepatitis B and C antibodiesVDRL serologyserum protein electrophoresiskidney biopsy This disease may also alter the results of the following tests: urinary casts triglyceride protein electrophoresis - urineserum ironcholesterol testalbumin
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 inhibitors (ACEI) 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 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.
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 thrombosisacute renal failurechronic 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.