Myositis

Myositis is a group of rare musculoskeletal conditions that cause inflammation in the muscles, leading to weakness, pain, and fatigue. This disease affects thousands of people worldwide, impacting their daily lives and overall quality of life. Let's explore the various types of myositis disease and myositis causes and risk factors. It delves into the symptoms, potential complications, and diagnostic methods used to identify the condition. 

What is Myositis?

Myositis is a group of rare conditions characterised by muscle inflammation. The term 'myositis' literally means muscle inflammation. It is a type of myopathy that refers to diseases affecting the skeletal muscles that connect to bones. Myositis disease can occur at any age, including in children, and it typically affects the muscles around the shoulders, hips, and thighs.

Myositis is an autoimmune disorder where the body's immune system mistakenly attacks healthy muscle tissue. In a healthy immune system, inflammation is a protective response to injury or infection. However, in myositis, unnecessary inflammation occurs, causing muscle problems.

Types of Myositis

Myositis encompasses several distinct subtypes, each with unique characteristics. These include:

• Dermatomyositis (DM): DM causes myositis with muscle weakness and inflammation, accompanied by a distinctive skin rash, often appearing as a purplish discolouration over the eyelids. 
• Juvenile Dermatomyositis (JDM): This is the childhood variant of DM, primarily affecting girls.
• Polymyositis (PM): PM leads to muscle weakness and inflammation in adults, particularly women. 
• Inclusion Body Myositis (IBM): IBM is a progressive muscle disorder characterised by weakness, inflammation, and wasting and typically affects men over 50. It is the most common acquired muscle disease in this age group.
• Antisynthetase Syndrome: It may occur as a complication in individuals with PM or DM. It involves the presence of specific autoantibodies and carries a risk of interstitial lung disease. 

Causes and Risk Factors of Myositis

Myositis is considered an autoimmune disorder, where the body's immune system mistakenly attacks healthy muscle tissues. Genetic alterations, particularly in the human leukocyte antigen (HLA) complex, may increase a person's risk of developing myositis. The HLA complex plays a vital role in helping the immune system distinguish between the body's own proteins and foreign invaders.

Environmental triggers also have an impact on myositis development. These include:

• Infections: Viral infections, such as the common cold, influenza, and HIV
• Medications: Statins and alpha-interferon 
• Other Autoimmune Conditions: Lupus, rheumatoid arthritis, and scleroderma are linked with an increased possibility of developing myositis. 
• Exposure to Ultraviolet Light and Toxins: They are also identified as potential risk factors.

Symptoms of Myositis

• Muscle Weakness: It often develops gradually and can be subtle at first. Individuals may experience difficulty performing everyday tasks such as climbing stairs, brushing hair, or getting in and out of cars.
• Increased Risk of Falls: The muscles around the shoulders, hips, and thighs are commonly affected, leading to an increased risk of falls.
• Red or Pink Rash: In dermatomyositis, a distinctive red or pink rash may appear on the upper eyelids, face, neck, and back of hands and fingers. 
• Other Myositis Symptoms: These include: 
  • Muscle pain
  • Tenderness to touch
  • Occasional swelling
  • Some people may feel generally unwell
  • Weight loss
  • Night sweats
  • Trouble swallowing (dysphagia) 
  • Difficulty breathing due to weakened throat or diaphragm muscles 
  • Fatigue and difficulty sustaining physical efforts 

Complications

Myositis can lead to various complications affecting multiple body systems. 

• Interstitial Lung Disease (ILD): It occurs in approximately 23% of individuals with dermatomyositis or polymyositis. ILD can cause shortness of breath, a dry cough, and reduced lung function. In some cases, it may progress rapidly, leading to a poor prognosis.
• Cardiac Complications: They are reported in up to 30% of patients with myositis. These can include arrhythmias, heart failure, and coronary artery disease. 
• Gastrointestinal Issues: Dysphagia (difficulty swallowing) and delayed gastric emptying may also occur.
• Aspiration Pneumonia: Myositis can affect breathing and swallowing muscles, potentially leading to aspiration pneumonia.
• Autoimmune Conditions: Some individuals with myositis may develop overlapping autoimmune conditions, such as rheumatoid arthritis, lupus, or scleroderma. 
• Calcinosis: Children with juvenile dermatomyositis may experience calcinosis, which involves painful calcium deposits in damaged muscles. 
• Cancer: In rare cases, myositis has been associated with an increased risk of cancer, mainly in adults over 40 with dermatomyositis. 

Diagnosis

• Medical History and Physical Examination: Doctors ask about symptoms, their onset, and any factors that may worsen or improve them. They also assess muscle strength and examine any skin abnormalities.
• Blood Tests: These tests measure levels of muscle enzymes like creatine kinase (CK) and aldolase, which can indicate muscle damage. Antinuclear antibody (ANA) tests and myositis-specific antibody panels help identify autoimmune activity.
• Nerve Conduction Studies and Electromyography (EMG): These tests evaluate muscle and nerve function.
• Magnetic Resonance Imaging (MRI): They can reveal muscle inflammation over a large area. 
• Biopsy: Doctors remove a small piece of muscle tissue for microscopic analysis.

Treatments for Myositis

While there is no cure for myositis, various treatment modalities can manage symptoms and improve quality of life. These include:

• Medication: Corticosteroids are often the first-line myositis treatment. These drugs reduce inflammation and ease muscle pain. 
• Immunosuppressants: They are frequently prescribed alongside corticosteroids to help control the immune system's attack on healthy muscle tissue.
• Biological Therapies: Doctors sometimes recommend biological drugs when other treatments prove ineffective. These medicines target specific components of the immune system to decrease inflammation. 

When to See a Doctor

Individuals should visit a doctor immediately if they experience new muscle weakness, pain, or other symptoms that persist over a few days. In some cases, early symptoms of myositis may include a dry cough, which can occur before skin and muscle symptoms appear. This lung condition has the potential to be serious, making prompt medical treatment vital. 

Emergency medical care is necessary if an individual suddenly loses the ability to move a part of their body, experiences difficulty breathing, or has trouble swallowing. 

Prevention

While there is no known way to prevent myositis, individuals can take steps to maintain overall health and potentially reduce the impact of the condition. These are:

• Regular Exercise and Physical Therapy: Engaging in physical activity helps keep muscles strong, prevents atrophy, and improves quality of life. 
• A Healthy Diet: Consuming a balanced, anti-inflammatory diet rich in organic fruits, vegetables, whole grains, and omega-3 fatty acids may help diminish inflammation and support overall well-being. 
• Special Dietary Considerations: These may include limiting salt intake, increasing potassium-rich foods, and managing carbohydrate consumption to help control blood sugar levels. 
• Dietary Supplements: Calcium, vitamin D, and omega-3 fatty acids may also benefit individuals with myositis.

Conclusion

Myositis is a complex and challenging condition that has a significant impact on the lives of those affected. While there's no cure for myositis yet, ongoing research offers hope for better treatments in the future. In the meantime, a combination of medical care, physical therapy, and lifestyle changes can help many people with myositis lead fulfilling lives. 

FAQs

1. Who usually gets myositis?

Myositis can affect people of all ages, but certain types are more common in specific groups. Dermatomyositis is the most prevalent form in children, while polymyositis typically affects adults over 20, with women being more susceptible. Inclusion body myositis predominantly affects individuals over 50, with men being more prone to this type.

2. Can you cure myositis?

There is no cure for myositis, but treatment can often put the condition into remission. Most people with myositis have it for the rest of their lives. However, with proper management, many patients can lead active lives and experience significant symptom relief.

3. How long does myositis last?

Myositis is typically a chronic condition that lasts a lifetime. However, the duration and intensity of symptoms can vary significantly among individuals. Some may experience only one period of acute illness, while others may struggle with symptoms for years.

4. What age does myositis start?

Myositis can develop at any age, but the onset varies and depends on the specific myositis type. Juvenile dermatomyositis typically appears in children between 5 and 15 years old. Adult-onset dermatomyositis and polymyositis usually begin between 30 and 50 years of age. Inclusion body myositis tends to affect individuals over 50. The age of onset can influence the disease course and treatment approach. Early-onset cases, particularly in children, may have a better prognosis with prompt treatment. Late-onset myositis, especially inclusion body myositis, can be more challenging to treat.

Dr. Sandeep Kharkar

MBBS, MD (Int Med),PGCC (Rheumatology)
Ganga CARE Hospital Limited, Nagpur

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