A rare health condition that causes the immune system to attack the muscles is called polymyositis. It often causes inflammation and weakness in the muscles located in the center of the body. As a result, it may lead to severe and even life-threatening complications. In general, it is advised to see a doctor if you experience muscle weakness, pain, or extreme tiredness without an obvious reason.
In other words, this disorder is an autoimmune disease and a type of myositis. This condition causes chronic (long-term) inflammation in the muscles that eventually leads to muscle weakness. However, in people with polymyositis, the inflammation occurs in multiple muscles at the same time. It often affects muscles closer to the center of the body. These include the neck, abdomen (belly), back, chest, hips, thighs, and arms.
Unfortunately, there is no way to cure this condition because experts do not fully understand why it happens. In addition, this condition occurs quite rarely and affects about 25 out of every 100,000 people each year in the U.S.
Symptoms
Usually, people who develop polymyositis experience the following symptoms. These include:
- Dyspnea (shortness of breath)
- Fatigue (extreme tiredness)
- Joint pain
- Fever
- Unusual weight loss
- Stiffness
- Muscle tenderness or pain
- Weakness of the affected muscles
- Speaking problems
- Dysphagia (swallowing problems)
Some people with polymyositis can also have problems with moving or performing daily activities. These include standing up after sitting, climbing stairs, lifting objects, and reaching over their heads. It is very important to see a doctor if any of the previous symptoms occur because they can cause life-threatening complications.
Causes
Healthcare providers do not fully understand what causes this condition. However, an autoimmune disorder causes the immune system to attack healthy cells instead of viruses, bacteria, and other germs. Commonly, it is not possible to determine what causes polymyositis, but a reaction to medicines or other health conditions can trigger it. Check below some disorders that can trigger polymyositis:
- Systemic lupus erythematosus
- Rheumatoid arthritis
- Scleroderma
- COVID-19
- Influenza (the flu)
- The common cold
- HIV infection
Risk Factors
While anyone can develop this condition, some people are more likely to develop it. Check below some examples:
- Sex – Women are twice as likely to develop polymyositis compared to men.
- Other autoimmune disorders (including rheumatoid arthritis)
- Age – In most cases, this condition affects people between the ages of 30 and 60.
What Happens if Polymyositis is Left Untreated?
People with this disorder can also experience some complications, especially if they leave it untreated. Check below some of them:
- Myocarditis
- Congestive heart failure
- Arrhythmia (irregular heart rhythm)
- Lung diseases (such as interstitial lung disease, aspiration pneumonia, and others)
- Raynaud’s phenomenon
- An increased risk of certain types of cancer
This document does not contain a full list of complications of polymyositis. However, you can consult with your healthcare professional about ways to reduce the risk of developing them. In addition, there is no way to prevent this condition because experts do not fully understand why it happens.
Diagnosis
In most cases, the diagnosis of this condition begins with a physical examination. Doctors may also ask some questions about the symptoms and medical history to get more clues about your disease. However, to rule out or confirm this disorder, doctors often perform the following tests and procedures. Check below some examples:
- Blood tests – These tests are often done to check for muscle enzymes or antibodies that cause damage to muscles.
- MRI (magnetic resonance imaging) – This is an imaging test used to get detailed images of the muscle structures and organs in the body. In such cases, it helps check for inflammation in the muscles.
- EMG (electromyography) – This test helps identify unusual muscle activity.
- Muscle biopsy – During this procedure, doctors will take a small sample of the affected muscle for testing. It shows damage and the overall health of the muscle tissue.
Treatment
Unfortunately, there is no way to cure this condition. That’s why the treatment goal is to relieve the symptoms and improve your quality of life. In general, there are a lot of people who reach a period of remission (there is no inflammation in the affected muscles). Check below some treatment options often recommended by doctors for people with polymyositis:
- Corticosteroids – This group of medications is primarily used to reduce inflammation.
- Immunosuppressants – These medicines are used to suppress the immune system’s activity. Therefore, it helps relieve the symptoms and reduce damage to the muscles.
- Intravenous immunoglobulin (IVIG) – This treatment involves injecting extra antibodies into one of the veins to redirect the immune system. Thus, it cannot attack the body’s tissue. IVIG works like a distraction.
- Physical therapy – During this therapy, a therapist will help you learn exercises to improve the affected muscles. It can also help reduce the frequency of the polymyositis episodes in the future.
Frequently Asked Questions
Is polymyositis hereditary?
According to some recent studies, this condition has a genetic component. It means people with specific genetic mutations can pass them to their biological children during pregnancy. This significantly increases the risk of developing polymyositis. While this condition cannot be prevented, you can perform some genetic tests before pregnancy to make sure you do not have these abnormal genes. It is very important to understand the risks of having children with polymyositis.
What is the life expectancy of someone with polymyositis?
In most cases, the condition itself does not affect life expectancy. However, this disorder can cause serious and even life-threatening complications. These include difficulty breathing, severe muscle weakness, and others.
What can be mistaken for polymyositis?
There are some disorders that can be mistaken for polymyositis. Check below some examples:
- Inclusion body myositis
- Hypothyroid myopathy
- Immune-mediated necrotizing myopathy
- Muscular dystrophy
- Amyotrophic lateral sclerosis
- McArdle disease
- Scleroderma
This document does not contain all possible conditions that can be mistaken for polymyositis. Ask your healthcare provider if you have additional questions.
