Membranous Nephropathy
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Membranous nephropathy (MN) is a condition in which the body’s immune system targets the filtering membranes within the kidneys. These crucial membranes are responsible for removing waste products from the bloodstream.
Each kidney contains thousands of minuscule filtering units called glomeruli, comprising incredibly fine blood vessels with only three layers: endothelial cells forming a single layer on the inner side of the blood vessel, podocytes creating a single layer on the outer side, and a thin glomerular basement membrane (GBM) sandwiched in between these layers.
The glomerular basement membrane acts as a filter. MN can develop suddenly or gradually worsen over an extended period, often remaining undetected in some individuals for many years.
Causes
Most cases of MN are now understood to be caused by an antibody that targets a protein on the podocyte known as the phospholipase A2 receptor (PLA2R). In individuals with MN, the immune system produces antibodies, which are proteins that typically aid in fighting infections. However, in this condition, instead of targeting an infection, these antibodies attack the podocytes. As a result, the podocytes become unable to retain certain proteins in the bloodstream, leading to their leakage into the urine. This form of MN is referred to as primary MN. Less commonly, MN can be caused by other factors (secondary MN), such as autoimmune disorders (where the body attacks its own cells) like lupus, cancer, certain medications, hepatitis B virus, or parasitic diseases like malaria.
Symptoms
Due to damaged podocyte cells, the main symptoms of MN are caused by protein loss in the urine. Nephrotic syndrome is the collective name for MN’s signs and symptoms. Nephrotic syndrome warning signs include:
- Weight gain: Due to the edema, people typically acquire water weight.
- Elevated blood pressure, particularly if renal failure develops concurrently with MN.
- Edema (swelling brought on by fluid retention, typically affecting the legs and feet).
- Blood protein levels that are below typical.
- Proteinuria (foamy-appearing urine brought on by excessive protein levels).
- Elevated cholesterol level.
- Fatigue.
Some individuals with MN may not experience noticeable symptoms. In such cases, doctors may detect signs of MN during a routine health check-up or while conducting tests for other health issues.
Risk factors
A greater risk group for MN includes individuals who are:
- More than 40 years old
- Caucasians. In general, Caucasians are more at risk than people of other races, although MN can affect anyone.
- Having a disease like lupus or cancer that can harm the kidneys.
Diagnosis
You ought to see a nephrologist if you experience any nephrotic syndrome symptoms, such as protein in your urine and edema or diminished kidney function. A physician who focuses on kidney illnesses and problems is known as a nephrologist. To confirm an MN diagnosis, your nephrologist will conduct a number of tests. These tests might be:
- Urine test: Determining the amount of protein and blood in your urine.
- Blood test: Obtaining a blood sample to check the protein and fat content.
- Glomerular Filtration Rate (GFR): Measuring kidney function by examining a blood sample.
- Antibody test: To assess the levels of the anti-phospholipase A2 receptor antibody in the blood.
- Kidney biopsy: Obtaining a little sample of kidney tissue with a needle and sending it to a lab to be tested for the presence of an MN-related antibody.
Treatment
The treatment for MN is dependent on its type and cause. If a person has primary MN, with moderate urine protein levels, stable kidney function, and no complications like blood clots, the nephrologist might decide to pursue non-immunosuppressive treatments. In certain cases, MN can resolve on its own over a span of six to 12 months without the use of medications to suppress the immune system.
These remedies could consist of:
- Diuretics: Drugs that drain the body of extra fluid and reduce blood pressure.
- Angiotensin-Converting Enzyme (ACE) inhibitors: Medications that control high blood pressure, lower urine protein levels, and aid in reducing renal inflammation.
- Cholesterol-lowering medications (statins): assist in lowering the high cholesterol levels.
- Low-salt diet: Consuming less salt to lessen edema.
- Your nephrologist would most likely utilize immunosuppressive medication, though, if any of the aforementioned factors exist or the proteinuria does not get better during the observation period.
- Immunosuppressive therapy: These medicines can prevent the immune system from creating the antibody that assaults the kidneys (e.g., rituximab, corticosteroids, cyclosporine, and cyclophosphamide).
Treating the underlying illness may prevent kidney damage from advancing in some individuals with secondary MN.
