Membranous Nephropathy

What is membranous nephropathy?

Membranous nephropathy is a kidney disorder in which small blood vessels in the kidney (glomeruli) that filter wastes from the blood become inflamed and thickened. As a result, proteins leak from the damaged blood vessels into the urine (proteinuria). For many, loss of these proteins eventually causes signs and symptoms characteristic of nephrotic syndrome.

What are the symptoms of membranous nephropathy?

The following are symptoms of membranous nephropathy:

• Edema (swelling) in any area of the body
• Fatigue
• Foamy urine
• Poor appetite
• Weight gain
• Excessive urination, usually at night
• Elevated fat levels in the blood (hyperlipidemia)
• Increased protein levels in the urine (proteinuria)
• Decreased protein levels in the blood, particularly of the protein albumin

What causes membranous nephropathy?

In most cases of membranous nephropathy, there is evidence of autoimmune activity. The body’s immune system mistakes some of the body’s own tissues as foreign and attacks them with autoantibodies. These autoantibodies can damage the kidney’s filtering systems (glomeruli). Sometimes membranous nephropathy is brought on by other causes, which could include:

• Autoimmune disease, such as lupus erythematosus
• Infection with hepatitis B, hepatitis C, or syphilis
• Certain medications, such as gold salts and nonsteroidal anti-inflammatory drugs
• Solid cancerous tumors or blood cancers

Membranous nephropathy may also occur along with other kidney diseases, such as diabetic nephropathy and rapidly progressive (crescentic) glomerulonephritis.

How is membranous nephropathy diagnosed?

A doctor may use the following techniques to diagnose a case of membranous nephropathy:

• Physical exam
• Urinalysis
• Blood test
• Blood urea nitrogen (BUN)
• Creatinine clearance
• Lipid panel
• Kidney biopsy
• Antinuclear antibodies test (Anti-double-strand DNA if the antinuclear antibodies test is positive)
• Cryoglobulin test

What are the available treatments for membranous nephropathy?

The goal of membranous nephropathy treatment is to reduce symptoms and slow the progression of the disease. Controlling blood pressure is the most important way to delay kidney damage. 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 also be used, and high blood cholesterol and triglyceride levels should be treated to reduce the risk of atherosclerosis. Where can I find out more about membranous nephropathy?

• NIH
• National Kidney Foundation
• Mayo Clinic