Membranous nephropathy is a kidney disorder that leads to changes and inflammation of the structures inside the kidney that help filter wastes and fluids. The inflammation may lead to problems with kidney function.
Membranous nephropathy is caused by the thickening of part of the glomerular basement membrane. The glomerular basement membrane is a part of the kidneys that helps filter waste and extra fluid from the blood. The exact reason for this thickening is not known.
The thicker glomerular membrane does not work normally. Large amounts of protein are lost in the urine as a result.
This condition is one of the most common causes of nephrotic syndrome. It may be a primary kidney disease, or it may be associated with other conditions.
The following increase your risk for this condition:
A urinalysis may reveal large amounts of protein in the urine. There may also be some blood in the urine. The glomerular filtration rate (the "speed" at which the kidneys cleanse the blood) is usually nearly normal.
Other tests may be done to see how well the kidneys are working and how the body is adapting to the kidney problem. These include:
The goal of treatment is to reduce symptoms and slow the progression of the disease.
Controlling blood pressure is the most important way to delay kidney damage. The goal is to keep blood pressure at or below 130/80 mmHg. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) are the medicines most often used to lower blood pressure.
Corticosteroids and other drugs that suppress the immune system may be used.
High blood cholesterol and triglyceride levels should be treated to reduce the risk of atherosclerosis. However, a low-fat, low-cholesterol diet is usually not as helpful for people with membranous nephropathy. Medications to reduce cholesterol and triglyceride levels (most often statins) may be recommended.
A low-salt diet may help with swelling in the hands and legs. Water pills or diuretics may also help with this problem.
Low-protein diets may 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 does not respond to therapy.
This disease increases the risk for blood clots in the lungs and legs. Patients are occasionally prescribed blood thinners to prevent these complications.
Expectations (prognosis)
The outlook varies, depending on the amount of protein loss. Patients may have symptom-free periods and occasional flare-ups. In some cases, the condition may go away, either with or without therapy.
Review Date:
9/19/2011
Reviewed By:
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.
