What Is Membranous Glomerulonephritis?
The human kidney is made up of a number of different structures. These structures aid in the removal of wastes from the blood and the formation of urine. Changes in the structures of the kidney can cause swelling and inflammation. This condition is generally known as glomerulonephritis (GN).
Membranous glomerulonephritis (MGN) is a specific type of GN. MGN develops when inflammation of structures in the kidney cause problems with kidney function. MGN is known by other names that have a similar meaning. These include:
- extramembranous glomerulonephritis
What Causes Membranous Glomerulonephritis?
MGN can develop as a primary kidney disease, meaning that the disease is not caused by another condition. MGN that develops as a primary kidney disease has no known cause.
MGN can also develop as a result of underlying health conditions. You are more likely to develop this condition if you:
- have been exposed to toxins such as mercury
- use certain medicines, including penicillamine, trimethadione, or skin-lightening creams
- have infections that affect the immune system such as malaria, hepatitis B, endocarditis, or syphilis
- have melanoma (skin cancer)
- have an autoimmune disorder such as lupus, rheumatoid arthritis, or Grave’s disease
The disorder is very rare, occurring in two out of every 10,000 people (UMMC, 2012). MGN is most commonly diagnosed in patients over the age of 40.
What Are the Symptoms of Membranous Glomerulonephritis?
The symptoms of MGN are different for each person. You may have no symptoms at all. If symptoms develop, they typically include the following:
- swelling (edema) in the hands, feet, or face
- foamy urine
- excessive need to urinate at night
- weight gain
- poor appetite
MGN causes damage to your kidney, and that results in protein being filtered from the blood and into your urine. Because protein is needed by the body, a lack of protein leads to water retention and swelling. All these symptoms are associated and known as nephrotic syndrome.
How Is Membranous Glomerulonephritis Diagnosed?
Diagnosis of MGN is made by your doctor. If you have symptoms of MGN such as swelling, your doctor may order a urinalysis. This test will show if you have protein in your urine. Other tests may also be ordered to confirm diagnosis including:
- blood and urine albumin tests
- blood urea nitrogen (BUN)
- creatinine blood
- creatinine clearance
- lipid panel
- blood and urine protein
If these tests indicate the presence of MGN, your doctor may also order a kidney biopsy. This procedure will require your doctor to obtain a small sample of kidney tissue. The sample will be sent to a laboratory for analysis. The results of this test will help confirm your diagnosis.
Following diagnosis of MGN, your doctor may perform additional tests to see what may be causing your condition. Examples of tests include:
- antinuclear antibodies test
- antidouble-strand DNA
- blood tests to check for hepatitis B, hepatitis C, malaria, or syphilis
- complement levels
- cryoglobulin test
How Is Membranous Glomerulonephritis Treated?
There is no cure for MGN. Treatment focuses on controlling and reducing the symptoms of the disease. You may need to make changes in your diet, including reducing your salt and protein intake. You may also need to take medication to help control your blood pressure. Drugs known as corticosteroids may be prescribed by your doctor to suppress (quiet) your immune system. Water pills or diuretics may be used to reduce swelling. MGN may place you at risk for developing blood clots, and your doctor may prescribe blood-thinning medications to control this risk.
If MGN is caused by an underlying disorder, your doctor may also recommend treatment for the condition. Your specific treatment plan will be based on your particular health needs. Talk to your doctor to find out what treatments he or she recommends.
What Is the Long-Term Outlook for Patients With Membranous Glomerulonephritis?
The long-term outlook for patients with MGN varies. You may be free of symptoms for long periods of time and then develop flare-ups. This occurs in 60 percent of patients who have this disease. You will need to visit your doctor for regular checkups so he or she can monitor your condition. In some instances, the disease may resolve without treatment. According to the National Kidney Foundation, this occurs in 20 percent of patients who have this disease (NKF, 2010).
Unfortunately, many patients who develop MGN develop some irreversible kidney damage within two to 20 years of being diagnosed with the disease. In 20 percent of patients, end-stage renal disease or kidney failure will occur (NIH, 2012). If you have kidney failure, your doctor will prescribe dialysis. Dialysis cleans your blood when your kidneys no longer work. Patients with end-stage renal disease may also be eligible for a kidney transplant.