Membranous glomerulonephritis; Membranous GN; Extramembranous glomerulonephritis; Glomerulonephritis - membranous; MGN DefinitionMembranous 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. CausesMembranous nephropathy is caused by the thickening of a 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 thickened glomerular membrane does not work normally. As a result, large amounts of protein are lost in the urine. This condition is one of the most common causes of nephrotic syndrome. This is a group of symptoms and abnormal test results that include protein in the urine, low blood protein level, high cholesterol levels, high triglyceride levels, increased blood clot risk, and swelling. Membranous nephropathy may be a primary kidney disease, or it may be associated with other conditions. The following increase your risk for this condition:
The disorder occurs at any age, but is more common after age 40. SymptomsSymptoms often begin slowly over time, and may include:
Exams and TestsA physical exam may show swelling (edema). A urinalysis may reveal a large amount 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 often 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:
A kidney biopsy confirms the diagnosis. The following tests can help determine the cause of membranous nephropathy:
TreatmentThe 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 mm Hg. High blood cholesterol and triglyceride levels should be treated to reduce the risk for atherosclerosis. However, a low-fat, low-cholesterol diet is often not as helpful for people with membranous nephropathy. Medicines that may be used to treat membranous nephropathy include:
Low-protein diets may be helpful. A moderate-protein diet (1 gram [gm] of protein per kilogram [kg] of body weight per day) may be suggested. Vitamin D may need to be replaced if nephrotic syndrome is long-term (chronic) and does not respond to therapy. This disease increases the risk for blood clots in the lungs and legs. Blood thinners may be prescribed to prevent these complications. Outlook (Prognosis)The outlook varies, depending on the amount of protein loss. There may be symptom-free periods and occasional flare-ups. Sometimes, the condition goes away, with or without therapy. Most people with this disease will have kidney damage and some people will develop end-stage renal disease. Possible ComplicationsComplications that may result from this disease include:
When to Contact a Medical ProfessionalContact your health care provider if:
PreventionQuickly treating disorders and avoiding substances that can cause membranous nephropathy may reduce your risk. ReferencesRadhakrishnan J, Stokes MB. Glomerular disorders and nephrotic syndromes. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 107. Saha MK, Pendergraft WF, Jennette JC, Falk RJ. Primary glomerular disease. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 31. Salant DJ, Beck LH, Reich HN. Membranous nephropathy. In: Johnson RJ, Floege J, Tonelli M, eds. Comprehensive Clinical Nephrology. 7th ed. Philadelphia, PA: Elsevier; 2024:chap 21. | ||
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Review Date: 8/28/2023 Reviewed By: Walead Latif, MD, Nephrologist and Clinical Associate Professor, Rutgers Medical School, Newark, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. View References The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | ||
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Kidney anatomy
