Myositis refers to a group of rare chronic muscle diseases that are, most often, both idiopathic (no known cause) and autoimmune in nature. There is no known cure for myositis, but some patients may experience partial or complete remission with proper treatment.
Many researchers believe that most cases of myositis are caused by a malfunctioning immune system that mistakenly attacks the body’s normal, healthy tissues with swelling and inflammation, but other known causes include infections, injury, certain medications, electrolyte level imbalance, and thyroid and inherited diseases.
There are several different subtypes of myositis, the most common of which are:
- Dermatomyositis (DM): DM is the most easily recognized type of myositis and is most often characterized by a visible patchy skin rash, with or without muscle weakness. It is most common in women.
- Polymyositis (PM): This type of myositis is found mostly in adult women. It is characterized by weakness in the muscles closest to the trunk of the body, such as the neck, shoulder, abdomen, hip and back.
- Inclusion-Body Myositis (IBM): IBM affects more men than women and rarely occurs in people under 50. It progresses slowly and primarily causes muscle weakness in the thighs, forearms, and below the knees.
- Juvenile Myositis (JM): JM affects children under the age of 18. It is characterized by muscle weakness and skin rashes over the eyelids or over joints.
Individuals with myositis experience a wide range of symptoms, including:
- Muscle weakness, sometimes accompanied by pain
- Skin rashes on knuckles, chest, face and back
- General fatigue
- Difficulty swallowing (dysphagia) or breathing
- Persistent dry cough
- Trouble rising from a seated position, or getting up after a fall
The specialists at Lancaster Orthopedic Group are trained to recognize the signs and symptoms of myositis and muscle malfunction. Through a combination of personal and family health histories, blood tests, muscle biopsy, electromyograms (EMG), and magnetic resonance imaging (MRI), your physician will identify the condition and help determine the best course of treatment.