Have you heard of this disease? Let's talk about what Microscopic Polyangiitis (MPA) is!

Hello! Today we are going to talk about a condition that is rarely heard of, but can be very important. It is called microscopic polyangiitis, or in English `(Microscopic Polyangiitis)`, or `(MPA)` for short. Although the name may sound a bit complicated, let's try to understand it simply. Don't worry, I am here to explain it to you.

What exactly is this MPA?

Simply put, MPA is a rare disease in which the very small blood vessels in our body become swollen, or as doctors call it, inflamed. This swelling of blood vessels is commonly called vasculitis . Imagine, there are many thin veins in our body that carry blood like water pipes. When such veins swell from the inside, the blood flowing through them is obstructed. What happens then? Our important organ systems, that is, the parts of the body that need to be nourished by those blood vessels, can be damaged. The areas most commonly affected by MPA are:

• Kidneys
• Lungs
• Nervous system (things like our nerves)
• Skin
• Joints (where our bones join)

It is good to know that there is another type of vasculitis that has similar symptoms to MPA, called Granulomatosis with Polyangiitis (GPA). It was previously called Wegener's granulomatosis. The treatments for both diseases are very similar.

So, what exactly is this `Vasculitis`?

Vasculitis, as I mentioned earlier, is the swelling of blood vessels. When this happens, the walls of these blood vessels can become weak. Sometimes they can become weak and bulge like a balloon – doctors call this an aneurysm. Other times, these blood vessel walls can become very thin and burst. This causes blood to leak into the surrounding tissue. Just like a water pipe becomes blocked by a clot, vasculitis causes the blood vessels to become narrowed and sometimes completely blocked. Since blood cannot flow through them, the organs that receive oxygen and other nutrients from that blood vessel are damaged. MPA mainly affects small and medium-sized blood vessels .

Who is most likely to develop this MPA?

This is actually a very rare disease . According to statistics, it is said that between 13 and 19 out of every million people (ten hundred thousand) develop this disease. That means it is very rare, right? This disease can develop in anyone of any age , and there is no difference between men and women , both can develop it equally.

Why was this MPA created?

Doctors have not yet found a specific cause for the development of MPA.. This is not cancer, it is not a contagious disease, and it is not a disease that usually runs in families. However, research has largely found that our own immune system is responsible for this. Simply put, the immune system, which is like a soldier who is supposed to protect our body from diseases, mistakenly starts attacking its own blood vessels . That is when these blood vessels swell, causing damage to the organs. Isn't that unfortunate?

What are the symptoms of MPA? How do we recognize it?

Because MPA can affect multiple organ systems, the symptoms are very varied . Not everyone will experience the same symptoms. Some people may experience common symptoms such as:

• Feeling tired all the time, feeling sluggish
• Fever
• Appetite
• Weight loss

In addition, specific symptoms may occur depending on the organ affected. For example:

• If the lungs are affected: Difficulty breathing, or coughing up a small amount of blood.
• If the nervous system is affected: unusual sensations such as numbness in the limbs, later loss of feeling in those areas, or decreased strength in the limbs.
• If it affects the skin: Skin rashes, i.e., eczema -like spots.
• If muscles and joints are affected: pain in those areas.

The important thing is that even if MPA damages the kidneys, it may not show any symptoms in the early stages! The patient may not realize it until kidney function is severely impaired. That is why it is absolutely essential for doctors to perform a urine test in any case of ` vasculitis` .

One or more of these symptoms may occur together.

How do doctors diagnose MPA?

Diagnosing MPA is like an undercover investigation. Doctors gather information from many different sources. When the disease is suspected, they do the following:

• They ask about your medical history: what symptoms you have and how long you have had them.
• A physical examination is performed: to find out which parts of the body are affected and to rule out other diseases that show similar symptoms.
• Blood tests : to see which organs in the body are affected, especially `antineutrophil cytoplasmic antibodies (ANCA)`To check if there are antibodies in the blood. If this `(ANCA)` test is `positive`, it is good evidence to suspect that `(MPA)` disease is present. However, this blood test alone cannot prove that `(MPA)` is present, nor can it tell exactly how active the disease is.
• Urine tests: Check for excess protein or red blood cells in the urine (this is very important to know if the kidneys are affected).
• Imaging tests: X-rays, computed tomography (CT) scans, or magnetic resonance (MR) scans may be done to look for abnormalities in areas such as the lungs.

Once MPA is suspected, a small piece of tissue is taken from the affected organ and examined (a biopsy) . This is the only way to confirm whether you have vasculitis. However, a biopsy is only done if there are abnormalities that appear from medical tests, scans, or a physical examination.

What are the treatments for MPA? (Treatment)

The main goal of treatment for MPA is to control our immune system, which is malfunctioning. Immunosuppressive medications are the main drugs used for this. There are several types of these drugs, but each drug has side effects, so they should be used only under medical advice.

• If MPA has severely affected vital organ systems , corticosteroids are usually given along with another immunosuppressive drug, such as cyclophosphamide (Cytoxan®) or rituximab (Rituxan®).
• If the disease is not too severe , a drug called `` Methotrexate '' can be used first along with ``Corticosteroids''.

The main goal of treatment is to stop all damage caused by MPA and bring the disease to a point where it is completely under control. This is called a "remission." When the disease seems to be improving, doctors gradually reduce the dose of corticosteroids and eventually try to stop them altogether. If cyclophosphamide is used, it is given only until the remission is achieved (usually three to six months). Then, to maintain the remission, another immunosuppressant is switched to methotrexate, azathioprine (Imuran®) or mycophenolate mofetil (Cellcept®) is used. The length of this maintenance treatment can vary from person to person. In most cases, it is at least a year or two.These drugs are given, and then the doctors try to reduce the dose and stop it. Think about it, some of the drugs used for these treatments are also used for other diseases. For example, drugs called `(Azathioprine)` and `(Mycophenolate mofetil)` are given to prevent the body from rejecting the organ after organ transplants. Drugs called `(Methotrexate)` are also given for diseases like rheumatoid arthritis and psoriasis. Drugs called `(Cyclophosphamide)` and `(Methotrexate)` are also given in high doses for some types of cancer, and at that time they are also called `(chemotherapy)`. But don't be afraid , they are given for `vasculitis` in doses that are 10 to 100 times lower than the doses given for cancer. Here, the main function of these drugs is not to kill cancer cells, but to control the activity of the immune system. Rituximab is a drug in a class of drugs called biologic agents. It works by targeting a specific part of the immune system. Recent research has found that Rituximab is as effective as Cyclophosphamide in treating severe MPA.

Because these medications weaken the immune system , there is a risk of developing serious infections. In addition, there are side effects inherent in each immunosuppressant drug. Therefore, it is extremely important to be constantly under medical supervision for side effects when using these drugs. Even if the drug is tolerated initially, the situation may change over time. Therefore, it is very important to continue to follow medical advice and undergo the necessary tests. Sometimes, even after stopping the drug, you have to be careful about long-term side effects.

What are the prospects for recovery for MPA patients? (Outlook)

Because MPA is a rare disease, it is difficult to give exact statistics on recovery. However, on average, more than 80% of people with MPA are free of the effects of the disease after five years. These results vary depending on the severity of the disease. MPA can progress slowly, and although it is a serious disease, most patients recover very well . By starting treatment early and being under close medical supervision, damage to the organs can be minimized. Even those with the most severe cases of MPA can achieve a period of remission if they start treatment early and do what their doctors tell them to do. Even after a period of remission, MPA can still come back. This is called a "relapse." This happens to about 50% of people with MPA. This recurrence may be similar to the symptoms you had when you were first diagnosed, or it may be different. To reduce the risk of a severe recurrence,If you develop any new symptoms, it is important to report them to your doctor immediately. It is also important to see your doctor regularly for blood tests and imaging tests. Treatment for a relapse is the same as for someone who has been newly diagnosed with the disease. Many people with MPA can go into remission again.

So, what are the most important things to remember from what we've talked about?

Okay, we've talked a lot about this `(MPA)` now. The most important things you need to remember from all of this are these:

• (MPA) is a rare but potentially serious disease in which the body's small blood vessels swell due to a malfunction of the immune system.
• It most commonly affects the kidneys, lungs, nerves, skin, and joints . Although the kidneys are particularly affected, there may be no symptoms at first .
• It is extremely important to diagnose the disease and begin treatment early.
• Treatment involves medications that suppress the immune system. Regular medical monitoring and testing are essential when using these.
• Even if the disease goes away (remission), it can come back (relapse) . So be aware of new symptoms.
• Always talk openly with your doctor , ask questions, and share your feelings. That's the best thing to do.

I hope this information is helpful to you. If you have any concerns about any symptoms, please do not forget to seek medical advice.