Muscle disease has many causes. These include infections, medications, muscle injuries, hereditary diseases that affect muscle function, disturbances in electrolyte levels, thyroid disease (hyper or hypothyroidism).
However, it is not known what causes inflammatory myopathies. As with all autoimmune diseases, there is an abnormal functioning of the immune system (waging war against its own tissue). This is an abnormal response to muscle cells and blood vessels.
How are inflammatory myopathies diagnosed?
The main reasons for bringing patients to the doctor may be decreased muscle strength, skin rash or respiratory complaints. There is no sensory disturbance (findings such as numbness, tingling). In the muscle strength examination performed by the doctor, for PM and DM; Weakness is detected in the proximal muscles of the shoulder, upper forearm, hip and upper leg. Skin eruptions typical of dermatomyositis are seen. IBM has asymmetrical muscle weakness, both proximal and distal (end).
The following tests are usually requested:
– In a blood test to measure the level of various muscle enzymes: creatine phosphokinase (CPK), aldolase, lactate dehydrogenase (LDH), serum glutamic oxolo-acetic transferase (AST= SGOT), serum glutamic-pyrivate dehydrogenase (ALT=SGPT); increase in muscle enzymes.
-Electromyogram (EMG); It measures the electrical activity of the muscle. It is used to show muscle weakness.
-Muscle biopsy-A small sample is taken from the involved muscle and examined. It is performed to demonstrate inflammatory myopathy and to exclude other myopathy-causing diseases.
-Magnetic resonance imaging (MRI): Not routinely used for the diagnosis of PM, DM or IBM, but can guide the location of muscle biopsy by showing abnormal muscle.
By blood tests; myositis-specific antibodies (autoantibodies formed against muscle tissue) can be investigated. These tests give some information about the prognosis (how serious the disease is) rather than the diagnosis of myopathy.
How are inflammatory myopathies treated?
Corticosteroids: An oral corticosteroid, such as high-dose prednisone, is usually used for initial treatment of the disease. This reduces inflammation. Muscle enzymes in the blood tend to return to normal within 4-6 weeks after starting treatment. Most patients regain muscle strength within 2-3 months.
Combination therapy: Reducing the need for corticosteroids; thereby reducing the side effects and keeping the disease under control for a long time, other drugs into the treatment plan; methotrexate or azathioprine is added. In patients in whom these treatments are also insufficient, other treatments such as intravenous immunoglobulin or cyclophosphamide are started. corticosteroids; It has side effects such as thinning of the skin, decrease in bone density, cataracts, weight gain and changes in the distribution of body fat. Even muscle weakness can be a side effect. Because patients taking cortisone are at risk for osteoporosis, they should receive appropriate treatment to prevent it (calcium and vitamin D replacement, sometimes in addition to osteoporosis medications).
Other treatments: For patients with severe signs of disease or who do not respond to standard therapy, other treatment options are available. These are intravenous immunoglobulin (IVIG) or drugs that suppress the immune system such as cyclosporine, tacrolimus, mycophenolate mofetil, and rituximab.
Physical therapy: Physical therapy and exercise are important in the treatment of muscle diseases. In the early stages of the disease, bed rest (except for general needs such as toilet) is recommended as much as possible. However, after muscle enzymes return to normal, physical therapy is recommended to prevent steroid-induced muscle atrophy and joint contracture (joint deformity). Begin with light isometric exercises and gradually increase the intensity as the patient begins to gain muscle strength.
Recommendations for patients with inflammatory myopathy:
Myopathies are chronic (long-term) diseases. To help control the disease; Eat a healthy and balanced diet, exercise in line with the physiotherapist’s recommendation and maintain your ideal weight.
If you have dermatomyositis, protect yourself from the sun; The rash gets worse after sun exposure. Therefore, use sunscreen creams, long-sleeved clothing and a hat when going out.
People with myopathy may appear healthy and normal. It is important to inform employers, teachers, and family members to better understand the limitations associated with the disease.
