Nephrotic syndrome is a condition characterized by marked proteinuria, hypoalbuminemia, hyperlipidemia, and edema. (See What happens in nephrotic syndrome, page 796.) Although nephrotic syndrome isn’t a disease itself, it results from a specific glomerular defect and indicates renal damage. The prognosis is highly variable, depending on the underlying cause. Some forms may progress to end-stage renal failure.
About 75% of nephrotic syndrome cases result from primary (idiopathic) glomerulonephritis. Classifications include:
❑ In lipid nephrosis (nil lesions), the main cause of nephrotic syndrome in children, the glomerulus looks normal by light microscopy. Some tubules may contain increased lipid deposits.
❑ Membranous glomerulonephritis, the most common lesion in adult idiopathic nephrotic syndrome, is characterized by uniform thickening of the glomerular basement membrane containing dense deposits and eventually progresses to renal failure.
❑ Focal glomerulosclerosis can develop spontaneously at any age, follow renal transplantation, or result from heroin abuse. Reported incidence of this condition is 10% in children with nephrotic syndrome and up to 20% in adults. Lesions initially affect the deeper glomeruli, causing hyaline sclerosis, with later involvement of the superficial glomeruli. These lesions generally cause slowly progressive deterioration in renal function. Remissions occur occasionally.
❑ In membranoproliferative glomerulonephritis, slowly progressive lesions develop in the subendothelial region of the basement membrane. Lesions may follow infection, particularly streptococcal infection. This disease occurs primarily in children and young adults.
Other causes of nephrotic syndrome include metabolic diseases such as diabetes mellitus; collagen-vascular disorders, such as systemic lupus erythematosus and periarteritis nodosa; circulatory diseases, such as heart failure, sickle cell anemia, and renal vein thrombosis; nephrotoxins, such as mercury, gold, and bismuth; allergic reactions; and infections, such as tuberculosis or enteritis. Other possible causes are pregnancy, hereditary nephritis, multiple myeloma, and other neoplastic diseases. These diseases increase glomerular protein permeability, leading to increased urinary excretion of protein, especially albumin, and subsequent hypoalbuminemia.
Nephrotic patients have an increased risk of infection, particularly of peritonitis.
The dominant clinical feature of nephrotic syndrome is mild to severe dependent edema of the ankles or sacrum, or periorbital edema, especially in children. Edema may lead to ascites, pleural effusion, and swollen external genitalia. Accompanying symptoms may include orthostatic hypotension, lethargy, anorexia, depression, and pallor. Major complications are malnutrition, infection, coagulation disorders, thromboembolic vascular occlusion, and accelerated atherosclerosis.
Consistent proteinuria in excess of 3.5 g/24 hours strongly suggests nephrotic syndrome; examination of urine also reveals increased number of hyaline, granular, and waxy, fatty casts, and oval fat bodies. Serum values that support the diagnosis are increased cholesterol, phospholipids, and triglycerides and decreased albumin levels. Histologic identification of the lesion requires kidney biopsy. Other tests may be done to rule out metabolic causes.
The goals of treatment of nephrotic syndrome are to relieve symptoms, prevent complications, and delay progressive kidney damage. Treatment of the causative disorder — possibly lifelong — is necessary to control nephrotic syndrome. Corticosteroid, immunosuppressive, antihypertensive, and diuretic medications may help control symptoms. Antibiotics may be needed to control infections. Angiotensin-converting enzyme inhibitors may significantly reduce the degree of protein loss in urine and are therefore typically prescribed for the treatment of nephrotic syndrome.
Treatment of hypertension and of high cholesterol and triglyceride levels are also recommended to reduce the risk of atherosclerosis and complications. Dietary limitation of cholesterol and saturated fats may be of little benefit because the high levels that accompany this condition seem to result from overproduction by the liver rather than from excessive fat intake. 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 g/kg of body weight per day) is usually recommended. Sodium may be restricted to help control edema. 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.
Supportive treatment consists of protein replacement with infusion of salt-poor albumin or with a nutritional diet of 1.5 g protein/kg of body weight, with restricted sodium intake of 0.5 to 1 g/day; diuretics for edema; and antibiotics for infection.
Some patients respond to an 8-week course of corticosteroid therapy (such as prednisone), followed by a maintenance dose. Others respond better to a combination course of prednisone and azathioprine or cyclophosphamide.
Patient care includes identification and treatment of the underlying cause accompanied by supportive care during treatment.
❑ Frequently check urine protein. (Urine containing protein appears frothy.)
❑ Measure blood pressure while the patient is supine and also while he’s standing; immediately report a drop in blood pressure that exceeds 20 mm Hg.
❑ After kidney biopsy, watch for bleeding and shock.
❑ Monitor intake and output and check weight at the same time each morning — after the patient voids and before he eats — and while he’s wearing the same kind of clothing. Ask the dietitian to plan a high-protein, low-sodium diet.
❑ Provide good skin care because the patient with nephrtic syndrome usually has edema.
❑ To avoid thrombophlebitis, encourage activity and exercise, and provide antiembolism stockings as ordered.
❑ Watch for and teach the patient and his family how to recognize adverse drug effects, such as bone marrow toxicity from cytotoxic immunosuppressants and cushingoid symptoms (muscle weakness, mental changes, acne, moon face, hirsutism, girdle obesity, purple striae, amenorrhea) from long-term steroid therapy. Other steroid complications include masked infections, increased susceptibility to infections, ulcers, GI bleeding, and steroid-induced diabetes; a steroid crisis may occur if the drug is discontinued abruptly. To prevent GI complications, administer steroids with an antacid or with cimetidine or ranitidine. Explain that steroid adverse effects will subside when therapy stops.
❑ Offer the patient and his family reassurance and support, especially during the acute phase, when edema is severe and the patient’s body image changes.
Review other book chapters online related to Childhood nephrotic syndrome:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
What do you think about the features of this website?
Take our user survey and have your say:
Next articles: Tools & Services:
Medical Articles:
Signs and symptoms
Diagnosis
Treatment
Special considerations
Pictures
Book Source Details
More About Childhood nephrotic syndrome
More Medical Textbooks Online about Childhood nephrotic syndrome
Medical Books Excerpts
More About This Book:
Title: Professional Guide to Diseases (Eighth Edition)
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2005
ISBN: 1-58255-370-X
» Next page: Nephrotic syndrome (Handbook of Diseases)
Rate This Website
Medical Tools & Articles:
Forums & Message Boards
Search Specialists by State and City
By using this site you agree to our Terms of Use. Information provided on this site is for informational purposes only; it is not intended as a substitute for advice from your own medical team. The information on this site is not to be used for diagnosing or treating any health concerns you may have - please contact your physician or health care professional for all your medical needs. Please see our Terms of Use.
Copyright © 2009 Health Grades Inc. All rights reserved.
