Are your legs swollen? Is your urine foamy? This could be Membranous Nephropathy (MN).

Have you ever noticed that your legs and ankles just swell up? Or have you noticed that when you urinate, it's foamy? These are not symptoms to just ignore. They can be signs that something is wrong with your kidneys. Today we're going to talk about a rare but important condition that affects your kidneys. That's called Membranous Nephropathy (MN).

What is Membranous Nephropathy (MN)?

Simply put, Membranous Nephropathy (MN) is a condition where your immune system, the system that protects you from disease, attacks your own kidneys. Isn't it amazing? Our own defenses are attacking us.

Now look, inside our kidneys, there are millions of tiny filters that clean the blood. We call these glomeruli . Like a tea strainer, these glomeruli filter the unwanted waste products in the blood and pass them out of the body as urine. Another function of these filters is to keep important things like proteins that the body needs in the blood.

What happens to someone with MN is that the immune system, as I mentioned, attacks and damages these filters called glomeruli. When this damage occurs, the holes in the filters become larger. Then the proteins needed by the body start to filter through the filter and come out with the urine. This is the basic problem of this disease.

This condition can appear suddenly, or it can develop gradually over time. Sometimes, people may not even know they have this condition for years.

There are two main types of this disease.

We divide this condition of Membranous Nephropathy (MN) into two main categories. This classification is done based on the cause.

Do you also have these symptoms?

The main symptoms of MN disease are caused by the large amount of protein excreted in the urine, as I mentioned earlier. In medicine, we call the collection of symptoms caused by this condition Nephrotic Syndrome .

The main symptoms are these:

• Edema: Swelling, especially in the legs, ankles, feet, and sometimes the face and hands. This swelling occurs when there is a decrease in protein in the blood, causing water in the blood vessels to leak into the tissues.
• Excessive foamy urine (Proteinuria): Due to the high protein content in the urine, it may appear foamy, like soapy water.
• Extreme fatigue and exhaustion: You may feel tired all the time because your body is losing the energy and nutrients it needs.
• Sudden weight gain: This is not actually getting bigger, but rather weight gain due to water retention.
• High cholesterol: When the protein level in the blood decreases, our liver produces more fat and cholesterol to compensate.
• High Blood Pressure: Blood pressure can increase when the kidneys fail.
• Difficulty breathing: This condition can occur if fluid accumulates around the lungs.

Why does this happen? What are the reasons?

The reasons also vary depending on the two types we discussed earlier.

The cause of primary MN

I said that primary MN is an autoimmune condition. What happens here is that our immune system mistakenly identifies a special protein called phospholipase A2 receptor (PLA2R) in the kidney filters (glomeruli) as an "enemy." Then, it makes antibodies to destroy this PLA2R protein and attacks it. This fight is what causes those filters to become damaged and the protein to leak out.

Things that can cause secondary MN

Secondary MN is a result of something else. Here are some things that can affect it:

• Other autoimmune diseases: Diseases like Lupus and Rheumatoid Arthritis.
• Infections: Infections such as Hepatitis B, Hepatitis C, Malaria, and Syphilis.
• Cancer: Especially lung and colon cancer.
• Medications: Long-term use of medications such as some painkillers (NSAIDs) and penicillamine.
• Toxins: Exposure to heavy metals such as mercury.

What complications can this cause?

If MN is not treated properly, serious complications can develop over time.

• High cholesterol and heart disease risk: Increased fat in the blood increases the risk of conditions such as heart disease and stroke.
• Blood clots: When protein is excreted in the urine, proteins that prevent blood clotting are also excreted from the body. This can lead to blood clots forming in the veins of the legs. We call this Deep Vein Thrombosis (DVT) . If this blood clot breaks loose and gets stuck in a vein in the lungs, it is a serious and life-threatening condition called Pulmonary Embolism (PE) .
• Kidney Failure: If the disease is not controlled, the damage to the kidneys gradually increases, and eventually the kidneys may fail completely.

How does a doctor find this?

If you have the above symptoms, your family doctor will refer you to a kidney specialist (Nephrologist). He will perform several tests to accurately diagnose the disease.

What are the treatments for this?

Treatment depends on what type of MN you have and how severe your symptoms are. The main goal of treatment is to reduce symptoms and stop the disease from getting worse.

One or more of the following may be used as treatment:

• Blood pressure medications: Medications like ACE inhibitors and ARBs control blood pressure and also reduce the excretion of protein in the urine.
• Diuretics: These are also called "water pills." They help reduce swelling by eliminating excess fluid from the body as urine.
• Cholesterol-lowering drugs (Statins): These are given to control elevated cholesterol levels in the blood.
• Blood thinners: These are used to reduce the risk of complications such as DVT.
• Immunosuppressants: Drugs such as corticosteroids are given to suppress the immune system's activity and try to stop it from attacking the kidneys.
• Dietary changes: It is very important to reduce your intake of foods high in salt and fat . Your doctor will advise you on a suitable diet.

If these standard treatments are not enough to control the disease, the doctor may then move on to more powerful treatments called immunotherapy . Drugs like Rituximab and Cyclophosphamide are used to destroy the cells that produce antibodies that attack the kidneys.

For someone with secondary MN, treating the underlying cause (e.g., hepatitis infection, lupus) can stop or reduce kidney damage.

How is life with this disease?

The course of this disease varies from person to person. For some people, the disease resolves completely with little or no treatment. For others, the disease persists for years.

The best part is that less than 15% of people with MN go on to develop kidney failure, meaning the majority can live a normal life with treatment.

But the most important thing to remember is that this disease can recur even after treatment. Therefore, it is essential to visit the clinics and get tested at the scheduled times as prescribed by your nephrologist. Then, if there are signs of the disease reoccurring, treatment can be started immediately.