Myositis, which means muscle swelling, is a group of chronic diseases that causes muscle weakness that’s often accompanied by pain. It can be caused by an injury, infection, certain medications, or an autoimmune disease like rheumatoid arthritis. The types of myositis that affect adults include:

• Polymyositis: The most common type of myositis, this type causes muscle weakness in your trunk and surrounding areas, such as your back, hips, shoulders, and neck. It affects muscles on both sides of your body (symmetrical). People with this type of myositis often experience symptom flares — periods in which symptoms get worse, then improve. 
  
  
• Dermatomyositis: This type causes a skin rash and symmetrical muscle weakness in your trunk and surrounding areas. The rash can develop on your face, neck, chest, and back, as well as on joints such as the elbows, knuckles, knees, and toes.
  
  
• Inclusion body myositis: This type affects older adults and causes muscle wasting in addition to weakness, but it's not symmetrical like other forms of myositis. It can affect smaller muscles such as the forearms and calves.

In addition to muscle weakness and pain, myositis symptoms can include fatigue, difficulty moving your arms and legs, and swallowing or breathing difficulties. The combination of muscle weakness and difficulty moving can increase your risk of falling. 

Polymyositis and dermatomyositis can also cause fever, weight loss, and lung issues, as well as additional symptoms that are unique to the type of myositis — such as joint pain and Raynaud’s phenomenon (numbness in fingers and toes) in those with polymyositis, and light sensitivity in people with dermatomyositis. 

At University of Miami Health System, our rheumatologists have advanced experience treating all types of myositis. With locations throughout South Florida, you find expert care for myositis nearby.

Treatments

Immunosuppressive Medicines
Doctors use a variety of medicines to stop the immune system from attacking healthy tissues, including:

• Corticosteroids: slow the body's immune response to relieve swelling and pain
• Disease-modifying Antirheumatic Drugs (DMARDs): suppress the immune system broadly to prevent swelling
• Genetically Engineered Biologics: a newer type of DMARD that targets specific immune functions

Some of the medicines can be taken orally, but others are given as an injection. Doctors use ultrasound-guided injections, which allows us to locate the area that’s causing pain and guide the injection of medicine directly to the source.

Physical Therapy
Physical therapy can help strengthen the muscles affected by myositis and improve your flexibility. A physical therapist can design a customized stretching and exercise program to prevent muscle wasting and improve the range of motion in your joints and muscles.

Tests

Biopsies
Your doctor may take a sample of tissue to confirm a myositis diagnosis. A muscle biopsy can show whether there's muscle wasting, swelling, or damage. For dermatomyositis, doctors may take a skin sample to examine the rash more closely.

Blood Tests
Doctors use a variety of blood tests to help diagnose myositis, including an aldolase test and creatine phosphokinase test to examine muscle activity. They also use tests that provide information about antibodies (blood proteins) associated with myositis, such as an antinuclear antibodies (ANA) test and a myositis-specific antibodies (MSA) test.

Electromyogram (EMG)
EMG is a test that measures a muscle’s response to nerve stimulation. It uses electrodes and a current to evaluate your muscles and look for abnormalities. The test helps doctors determine what's causing muscle weakness, twitching, or pain, as well as identify nerve damage.

Magnetic Resonance Imaging (MRI)
A noninvasive magnetic resonance imaging scan — which uses magnetic energy and radio waves without radiation — allows your doctor to examine the area of muscle weakness or pain. Doctors may also use MRI or ultrasound (sound waves) to determine where to take a muscle biopsy.

Why Choose UHealth?

The latest treatments for myositis and other rheumatic diseases. In addition to treating patients, our rheumatologists conduct research to find better approaches for managing the disease. That means you receive care from specialists on the leading edge of myositis care. You have access to some of today’s most promising therapies through clinical trials — including treatments you can’t find anywhere else nearby.

Comprehensive care from a team of specialists. Myositis can affect different areas of your body, so our rheumatologists work with doctors in a full range of medical specialties to give you comprehensive, coordinated care — such as dermatologists, vascular specialists, pulmonologists (lung doctors), ophthalmologists, and others. 

Expert diagnosis and personalized attention for myositis. Muscle weakness and fatigue can be caused by many things, so it’s important to work with a doctor who has experience identifying and treating myositis. Our rheumatologists specialize in diagnosing myositis and designing treatment based on each person’s unique needs. 

Specialized care to improve your quality of life. Our rheumatologists work closely with physical therapists, pain management specialists, and other health care professionals to help manage symptoms such as muscle and joint pain, movement difficulties, and fatigue. We educate you about lifestyle changes that can improve symptoms — such as regular exercise and a healthy diet — and offer a wide range of therapies to help you feel better.