Myositis: Types, Symptoms, Causes, and Treatment

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

Myositis symptoms can differ based on the specific type, but some common signs typically seen across most forms 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 cause of myositis is unclear, but it’s thought to be an autoimmune disorder. 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: Contact with certain environmental elements, such as toxins, can potentially increase the likelihood 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

Doctors diagnose myositis by checking your symptoms, doing a physical exam, and using a few tests. Since this condition is rare and its symptoms are similar to other diseases, it may take some time to confirm the diagnosis.

Medical History and Physical Exam

The doctor will ask about your symptoms, when they started, and how they affect your daily activities. They may check your muscle strength and see how your body responds to certain movements. This helps them understand how severe the condition is.

Blood Tests

Blood tests help detect signs of muscle damage and inflammation. An increase in muscle-related enzymes, particularly creatine kinase (CK), can point toward myositis. These tests may also detect antibodies that suggest an autoimmune disorder.

MRI Scan

Magnetic Resonance Imaging (MRI) uses a powerful magnet and computer technology to produce clear, detailed images of the muscles. It helps identify areas of inflammation and shows how the muscles are affected over time.

Electromyography (EMG)

EMG is a test that measures how your muscles respond to nerve signals. The doctor inserts small needle electrodes into the muscles to check their electrical activity. This helps detect weak or damaged muscles.

Muscle Biopsy

A muscle biopsy is the most accurate test to confirm myositis. In this test, the doctor removes a small piece of muscle tissue and examines it under a microscope. It helps clearly identify muscle inflammation and damage.

Other Tests

In some cases, doctors may suggest additional tests such as nerve conduction studies or special blood tests to rule out other conditions and support the diagnosis.

Important Note

There is no single test that can confirm myositis. Doctors usually make the diagnosis by combining your symptoms, physical exam findings, and test results.

Treatment

There is no complete cure for myositis, but treatment can help control symptoms and improve quality of life. The main goal is to reduce inflammation, relieve pain, and keep muscles strong.

Medications

Doctors may prescribe different medicines based on the condition:

• Corticosteroids to reduce muscle inflammation
• Immunosuppressants to control the immune system
• IVIG (intravenous immunoglobulin) for severe or resistant cases
• Pain relievers to reduce discomfort

If myositis is caused by an infection, antibiotics may be used. If it is linked to a medicine, stopping that medicine can improve symptoms.

Physical Therapy and Exercise

Physical therapy is very important. Simple exercises and stretching help improve muscle strength and flexibility. They also reduce stiffness and prevent muscle loss.

Lifestyle Changes

Healthy habits can support treatment:

• Get enough rest
• Eat a balanced and nutritious diet
• Manage stress with activities like yoga or meditation
• Stay active with gentle exercises

Prevention

There is no sure way to prevent myositis because its exact cause is not always known. However, some simple steps can help reduce the risk and prevent symptoms from getting worse.

Maintain a Healthy Lifestyle

Eat a balanced diet with fruits, vegetables, and protein-rich foods. Regular light exercise helps keep your muscles strong and flexible.

Prevent Infections

Some cases of myositis may follow viral infections like a cold or flu. You can reduce your risk by:

• Washing your hands often
• Avoiding close contact with sick people
• Keeping your hands away from your face
• Staying up to date with vaccines

Avoid Triggers

Try to avoid things that may trigger symptoms, such as certain medicines, harmful chemicals, or too much sun exposure. Use sunscreen and protective clothing when outdoors.

Build Healthy Habits

• Get enough sleep
• Manage stress with relaxation techniques
• Avoid smoking and limit alcohol

Manage Other Health Conditions

If you have other health problems, especially autoimmune conditions, keep them under control with proper treatment.

Early Medical Care

Pay attention to early signs like muscle weakness or unusual pain. Getting medical help early can prevent the condition from getting worse.

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