Myositis: Symptoms and Causes

Myositis is a rare autoimmune condition that inflames the muscles, causing weakness, pain, and fatigue. There are several types of myositis, and the symptoms and causes may vary from person to person.

Types

The following are the main types of myositis, each with distinct characteristics and symptoms affecting muscle strength and function.

Polymyositis

Polymyositis affects multiple muscles simultaneously, usually those in the center of your body. It develops gradually over time and commonly affects adults, especially women.

Symptoms of polymyositis include difficulty performing everyday movements such as standing up, climbing stairs, lifting objects, and reaching over your head.

Dermatomyositis

Dermatomyositis is a type of myositis that not only affects your muscles but also your skin. It can develop quickly; early treatment is crucial to avoid severe complications. Anyone can develop dermatomyositis, including children who may have juvenile dermatomyositis.

In rare instances, dermatomyositis can be life-threatening, particularly within the first year of symptom onset. It can also increase the risk of developing certain types of cancer.

Inclusion Body Myositis

Inclusion body myositis is a muscle-wasting disease that mainly develops in people over 50. It leads to muscle weakness in the hands and lower legs and can also impact the swallowing muscles.

Symptoms of inclusion body myositis include difficulty using your hands and fingers for precise tasks like buttoning a shirt or gripping something small, and difficulty walking, standing, and swallowing.

Other Types

While polymyositis, dermatomyositis, and Inclusion Body Myositis are the most well-known forms of myositis, several other types also exist, each with distinct characteristics.

Anti-Synthetase Syndrome

Anti-synthetase syndrome is a systemic inflammatory disorder that impacts the muscles, lungs, and skin. Lung involvement can be serious, making early treatment essential. A persistent dry cough may appear before muscle or skin symptoms.

This condition is also linked to Raynaud’s phenomenon, where fingers and toes change color when exposed to cold. The skin may turn white, then blue, and feel extremely cold, followed by redness, swelling, and throbbing upon rewarming.

Previously, anti-synthetase syndrome was often mistaken for polymyositis or dermatomyositis, but it is now recognized as a distinct condition due to its unique symptoms.

Drug-Induced Myopathies

Certain medications can lead to muscle conditions that mimic myositis. The most common culprits are statins, which are prescribed to lower cholesterol. In most cases, discontinuing the medication results in symptom improvement. However, in rare cases, symptoms persist even after stopping the drug, leading to the development of myositis.

Immune-Mediated Necrotizing Myopathy

A newly identified form of myositis, immune-mediated necrotizing myopathy, causes rapid muscle cell death (necrosis). This results in severe muscle weakness, significantly affecting mobility and daily activities.

In rare instances, this condition can be induced by statin medications, which are commonly prescribed to reduce cholesterol levels.

Post-Infectious Reactive Myositis

This type of myositis can develop during or after certain viral infections. Even after the virus is eliminated, the immune system may continue to cause inflammation in the muscles for a few months.

Symptoms resemble polymyositis, including muscle pain and weakness. Fortunately, post-infectious myositis is usually mild and often resolves without medical intervention.

In rare instances, long-term viral muscle infections may occur in individuals with HIV.

Symptoms

The symptoms of myositis can vary depending on the type of myositis a person has. However, some common symptoms of myositis include:

1. Muscle weakness: It can develop in any muscle group, but it is most apparent in the arms, legs, and neck.
2. Muscle pain can vary from mild to intense and may be accompanied by tenderness and swelling in the muscles.
3. Fatigue: Muscle weakness in the throat can cause difficulty swallowing for some individuals with myositis.
4. Difficulty swallowing: Some people with myositis may have swallowing difficulties due to muscle weakness in the throat.
5. Skin rash: Dermatomyositis can cause a characteristic facial, neck, and chest rash.

Causes

The exact cause of myositis is unknown, but it is believed to be an autoimmune disease. In autoimmune diseases, the body’s immune system mistakenly attacks its own tissues, including muscles. Several factors that could increase the risk of developing myositis include:

1. Genetics: Certain genetic mutations may increase a person’s risk of developing myositis.
2. Infections: Some infections may trigger myositis in people who are genetically predisposed to the condition.
3. Environmental factors: Exposure to environmental factors, like toxins, may raise the risk of developing myositis.

Who Is at Risk for Myositis?

Myositis can affect anyone, but certain factors increase the risk.

• Age: Most cases occur between 45 and 64 years, with 8–10 new cases per 100,000 people annually. It is less common in younger (25–44) and older (65+) individuals (3–5 cases per 100,000 per year).
• Sex: Polymyositis and dermatomyositis are 2–3 times more common in women, while inclusion body myositis (IBM) affects men 1.5–2 times more than women.

Diagnosis

A diagnosis of myositis usually includes a physical exam, evaluation of your medical history, and recommended tests like blood tests, imaging, or a muscle biopsy. A muscle biopsy is a procedure where a small sample of muscle tissue is taken to be analyzed under a microscope for any indications of inflammation or damage.

Treatment

Treatment for myositis depends on the type and severity of the condition. Some common treatments for myositis include:

1. Medications: Experts will prescribe medicines as per your condition.
2. Physical therapy: Physical therapy can aid in enhancing muscle strength, flexibility, and range of motion.
3. Occupational therapy: Occupational therapy can assist individuals with myositis in discovering alternative methods to carry out daily tasks and adjust to muscle weakness.

Prevention

While there is no guaranteed way to prevent myositis, adopting certain lifestyle changes may lower the risk of developing the condition. These include:

• Maintaining a healthy diet and exercise routine: Regular exercise and a balanced diet can help keep the immune system healthy and lower the risk of developing autoimmune diseases.
• Avoiding exposure to toxins: Minimizing exposure to harmful substances like pesticides and industrial chemicals may lower the risk of developing myositis.

Who to Consult For Myositis and When?

If you experience any symptoms of myositis, it is important to see a doctor as soon as possible. You may be referred to a rheumatologist or neurologist by your primary doctor for specialized evaluation and care.

In addition to seeking medical attention, it is important to talk to your doctor about any medications or supplements you are taking, as some medications and supplements may worsen myositis symptoms.

Myositis can sometimes lead to serious complications, such as difficulty breathing, heart problems, and infections. If you notice any of these symptoms, get emergency medical help right away.

In summary, myositis is a rare autoimmune disorder that causes muscle inflammation, resulting in weakness, pain, and fatigue. There are several types of myositis, and the symptoms and causes may vary from person to person. While there is no surefire way to prevent myositis, maintaining a healthy lifestyle and avoiding exposure to toxins may help lower the risk of developing the condition. If you experience any symptoms of myositis, seek medical attention as soon as possible and talk to your doctor about treatment options.

Frequently Asked Questions