Microscopic Polyangiitis

A rare type of vasculitis that often causes inflammation of the blood vessels is called microscopic polyangiitis (MPA). Without immediate treatment, this condition can cause damage to multiple organs. The most common affected areas of the body are the kidneys, lungs, nerves, skin, and joints. However, it may affect other organs and structures in your body.

The name of this condition refers to how it affects you. For example, the term “Angiitis” is another name for vasculitis, “Poly” means many, and “microscopic” means small. In people with this condition, certain blood vessels become inflamed, which reduces blood flow to multiple parts of the body.

What Are The Symptoms of Microscopic Polyangiitis?

Usually, people who develop MPA experience different symptoms because they depend on several factors. For example, the severity of the condition, which part of the body is affected, gender, and age. Check some examples below:

Appetite changes
Unusual weight loss
Skin rashes (especially on the legs)
Fever
Extreme tiredness (fatigue)
Feeling sick or unwell
Cough (sometimes with blood)
Muscle, joint, or abdominal (belly) pain
Weakness, tingling, or numbness
Dyspnea (shortness of breath)
Eye redness or pain
Vision changes (such as blurred vision, double vision, or reduced vision)

Most of the time, MPA negatively affects the kidneys, but not always cause symptoms. Sometimes, it may cause blood in the urine (hematuria) or cloudy pee. Do not hesitate to visit a doctor if any of the previous symptoms occur. Otherwise, it may lead to serious complications (such as organ damage).

Causes and Risk Factors

This is an autoimmune disorder that occurs when the immune system mistakenly attacks healthy body parts instead of protecting them. Healthcare providers do not know what causes this disorder. However, some experts think antineutrophil cytoplasmic antibodies (ANCA) can contribute to this autoimmune disorder. That’s why this condition is also called MPA ANCA-associated vasculitis or ANCA vasculitis.

In general, antibodies are specific proteins produced by your immune system to identify and destroy invaders, such as bacteria, viruses, and other germs. However, ANCA are a type of autoantibody, which are proteins that mistakenly attack healthy structures in the body. Approximately 70% of people with MPA have ANCA in their blood.

While it is not possible to determine the cause of MPA, doctors have identified some factors that could increase your risk of developing it. Check some of them below:

Sex – Males are slightly more likely to develop MPA than females.
Age – Most diagnosed people are around age 50.
Other autoimmune disorders (such as rheumatoid arthritis)
Environmental triggers – These include exposure to Silica, UV (ultraviolet) light, and air pollution.
Medicines – There are some medications that may trigger MPA. For example, Propylthiouracil, Hydralazine, Minocycline, Allopurinol, and Levamisol-adulterated cocaine.
Infections – There is a bacterium called Staphylococcus aureus that significantly increases your risk of developing microscopic polyangiitis.
Renal insufficiency
Gastrointestinal problems
Smoking
Genetic factors – Doctors have also identified some genetic changes (mutations) in people with MPA. For example, HLA-DP, HLA-DR3, and alpha-1 antitrypsin genes.

What Are The Possible Complications of Microscopic Polyangiitis?

People who develop this condition may also experience serious and even life-threatening complications, especially if the original disorder is left untreated. Check some complications below:

Glomerulonephritis (kidney failure) – This is one of the most common complications of MPA (it affects about 80% of people). It causes kidney failure, which requires dialysis.
Respiratory failure/lung damage – These include diffuse alveolar hemorrhage (bleeding into the lungs), chronic interstitial fibrosis, and severe dyspnea (shortness of breath).
Peripheral neuropathy – Sometimes, people may experience nerve damage and the following symptoms. For example, numbness, tingling, and weakness.
Skin and gastrointestinal problems – This complication often causes skin ulcers, rashes, and abdominal pain often caused by reduced blood flow.
Treatment complications – People who use immunosuppressants may also experience osteoporosis (brittle bones), diabetes, and hypertension (high blood pressure).
Permanent organ damage

This document does not contain a complete list of complications, but you can consult with your doctor about measures to prevent them. In addition, there is no way to prevent MPA because doctors do not fully understand what exactly causes it.

Diagnosis

Doctors often diagnose this condition by learning as much as possible about your health. They may also ask some questions about your symptoms and medical history to gather more information about your condition. You should also inform your doctor if your symptoms come and go, and what activities seem to worsen them.

Mostly, diagnosing MPA requires your doctor to consider a differential diagnosis. This is a list of diseases that cause similar symptoms. However, to confirm or exclude MPA, doctors often perform the following tests and procedures. Check some examples below:

Blood test
Urinalysis (also known as a urine test)
Imaging tests – The following tests are used to get detailed images of different structures and organs in the body. Physicians usually perform a CT (computed tomography) scan, an X-ray, or an MRI (magnetic resonance imaging).
Biopsy – During this procedure, doctors will take a sample of the affected tissue or organ for testing.

Moreover, people who develop microscopic polyangiitis often need to see a rheumatologist. This is a healthcare provider specializing in treating inflammatory disorders.

Treatment

One of the most important parts of the MPA treatment is to reduce the symptoms, prevent serious complications (such as further damage to your blood vessels), and improve your quality of life. Most of the time, MPA is treated with a combination of prescription glucocorticoids (such as Prednisone) and immunosuppressants.

Commonly, the treatment begins with high doses of the previous medicines. Doctors often reduce the dose when you notice that your condition and symptoms improve. There are some people who reach remission. It means there is no longer inflammation in the body, which prevents further damage to the blood vessels and other organs. In addition, people who have reached remission will continue to administer immunosuppressants for a long time (sometimes, for the rest of their lives).

Frequently Asked Questions

When should I see my healthcare provider?

Usually, it is recommended to visit a doctor if you experience symptoms that resemble MPA or if the treatment that you get for this condition does not work. You should also inform your physician about all changes you notice during treatment.

Can microscopic polyangiitis be cured?

Unfortunately, it is not possible to cure this condition. That’s why the goal of the treatment is to get the condition in remission. However, you can be in remission for years and then experience symptoms again. When it occurs, doctors call it a relapse. Sometimes, people with MPA never have relapses.

What are the first signs of polyangiitis?

Usually, the first symptoms of this condition are very similar to those of a cold or flu. For example, extreme tiredness (fatigue), sinus problems (such as congestion, runny nose, and sinus pain), and others. However, the difference between these conditions and polyangiitis is that the symptoms do not disappear with regular treatment. If you have any other questions, ask your healthcare provider.