Inclusion body myositis, or IBM, is an inflammatory disease of the muscles. The inflammatory response involves cells and chemicals of the immune system infiltrating and damaging the muscles. There are two types of inclusion body myositis: a hereditary form and a sporadic form. It is important to consult with a physician for the diagnosis and treatment of health conditions and symptoms of disease.
Causes
The causes of sporadic IBM are not known. One theory advances the idea that aging and degeneration of the muscle leads to abnormal protein buildup and damage. Another theory posits that the immune system reacts to an unknown trigger and attacks the muscle. Whatever the trigger, the outcome is inflammation and degeneration of the muscle. The precise development of hereditary inclusion body myositis is also unknown. However, it has several different inheritance patterns and forms.
Symptoms and Signs
Inclusion body myositis develops differently in different people. In some, it progresses rapidly, affecting the legs more than the arms, while in others, it may progress slowly, possibly affecting the muscles close to the center of the body. The thigh muscles in the leg and finger flexors in the forearm are often affected first. This can make it difficult to walk and use the fingers. Progression of the disease can also make it difficult to coordinate swallowing.
Diagnosis
A thorough medical history, including a family history, and an account of all the symptoms, signs and time course, along with a physical exam, are the first steps toward diagnosis. After this, laboratory tests and imaging can be tailored to the individual case. Some people have elevated levels of the enzyme creatine kinase in the blood, which can be a clue, but is not specific for IBM. Also, nerve conduction studies, which measure the electrical activity of the muscles, can help ascertain the diagnosis. A muscle biopsy, in which a small amount of muscle is removed for special studies, can be very helpful.
Treatment and Prognosis
There is no treatment to stop the progression of the disease. Instead, symptoms are managed as needed. Preventing falls is an important element, and depending on the severity, the patient may require a walker or wheel chair. Physical therapy or special exercises may help to enhance quality of life. If trouble swallowing becomes too much of a problem, it may necessitate a feeding tube.
References
- "Harrison's Principles of Internal Medicine"; Anthony S Fauci, et al.; 17th Ed 2008
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar, et al.; 8th Ed 2009
