Dr. Shetty’s presentation to the Myositis Education and Support Program focused on inflammatory myopathies and their initial evaluation, testing, diagnosis, and treatment protocols.
Inflammatory myopathies are muscle diseases characterized by muscle weakness. The three major inflammatory myopathies are polymyositis, dermatomyositis, and inclusion body myositis. Each type has different findings:
One of the major effects of the inflammatory myopathies is difficulty in swallowing, known as dysphagia. If this occurs, it is important to bring this to the attention of your physician.
Muscle disease can also be associated with certain endocrinological problems, such as thyroid abnormalities.
Toxic myopathies refer to myopathies that are caused by medications such as steroids, chloroquine, colchicine, and statins.
Each type of inflammatory myopathy (polymyositis, dermatomyositis, and inclusion body myositis) has specific findings upon examination, electromyographic testing, muscle enzyme level, and muscle biopsy.
People who have muscle disease generally present with the following upon examination:
Onset can be gradual and progressive; there may be varying degrees of muscle pain or cramps. When these complaints are present, a detailed neurological exam is indicated in order to find the source of the weakness and to determine which muscles are affected.
Blood tests are also obtained to check muscle enzyme levels and to determine the presence of associated rheumatologic or connective tissue disorder markers that may be associated with myositis or muscle diseases. These tests, in conjunction with renal (kidney) and liver tests, are used to monitor inflammation and to rule out the possibility of medication toxicity.
The blood tests monitor levels of creatine kinase (CK, also known as creatine phosphokinase [CPK]). A rise in the CK level may be the first sign of a muscle disease flare and can occur prior to muscle weakness. It should be noted that CK levels are variable and are affected by race, gender, genetics, cholesterol-lowering drugs and activity level. All of these tests are conducted in order to determine the specific type of myopathy a person has.
Although family history can often be relevant, the absence of muscle disease in a family does not mean that the patient does not have muscle disease. History about family members is often incomplete. Many muscle diseases occur spontaneously or are not fully understood genetically.
Electromyography and Imaging
Further testing can include the use of electromyography (EMG) and imaging, such as MRI and ultrasound. These tests work in the following ways:
The goal of treatment is to decrease muscle inflammation and to prevent further muscle loss or injury. Medical treatment is individualized, and there are no defined guidelines in the approach to treatment. However, randomized controlled clinical trials are evolving in order to better define this.
It is important to note that all treatment options, responses, and effects are personalized and that each individual will respond differently to a given plan. The physician will be able to assess your response to treatment based on your own report of the status of your disease, change in rash, and examination of muscle strength.
As Dr. Shetty emphasizes, “Most importantly, the treatment is based on a very close interchange between physician and patient who, together, assess the response to immunosuppressive therapy. This dialogue enables the doctor and patient to arrive at a treatment plan that is optimal for the patient.”
Factors that are taken into consideration for treatment are:
Corticosteroids and Immunosuppressive Agents
Medications that are commonly used in myositis include corticosteroids and other immunosuppressive agents such as Imuran (Azothioprine), Cellcept, Methotrexate, and Rituxan (still in trial stages). Although corticosteroids are often have a wide range of side effects, their effectiveness makes them an initial treatment approach. The dosing is individualized to the patient and weighed against potential side effects.
Caution is urged against the prolonged use of high doses of steroids. It should also be noted that steroids can cause a myopathy, which is often reversed when steroid dose is tapered.
Indications for use of immunosuppressives other than steroids include: progression of clinical symptoms, poor response to steroids, evidence of organ involvement, relapse when steroids are tapered, and undesirable effects from steroids (osteoporosis, cataracts, diabetes, hypertension acne, weight gain, and mood changes).
Intravenous Immunoglobulin (IVIG)
IVIG is administered intravenously and is derived from pools of serum from healthy individuals. IVIG provides antibodies and has an immunomodulatory effect, which can be used to treat dermatomyositis and polymyositis where other treatments have not proved effective.
Learn more about the Myositis Education and Support Program, a free support and education group held monthly at Hospital for Special Surgery.
Summary by Suzan Fischbein, LCSW