What Is Inclusion Body Myositis?
Inclusion body myositis (IBM) refers to the inflammation that appears under the myometrium or in the center of the muscle fibers under the light microscope, and the filamentous inclusions in the muscle or nucleus are observed under the electron microscope Sexual myopathy, the course of which progresses slowly, and the affected muscle has a specific site, which may be related to immune mediation, or it may be a muscle degenerative disease. IBM is the most common inflammatory myopathy among people over 50 years old, and it can occur in both men and women, but it is more common in middle-aged and older men. The ratio of male to female is 3: 1.
- English name
- inclusion body myositis
- Visiting department
- Division of Rheumatology
- Multiple groups
- Middle-aged and elderly men
- Common causes
- Unclear, may be caused by immune-mediated, multi-factor genetic susceptibility
- Common symptoms
- Painless muscle weakness and muscle atrophy, both proximal and distal muscle groups can be affected, most commonly quadriceps involvement
Basic Information
Causes of inclusion body myositis
- The pathogenesis of this disease is not clear, it may be an immune-mediated, multi-factor genetic susceptibility to participate in the pathogenesis of muscle degeneration disease, secondary inflammation.
Clinical manifestations of inclusion body myositis
- Often insidious onset, chronic progress, mainly manifested as painless muscle weakness and muscle atrophy, proximal or distal muscle groups can be affected, most commonly quadriceps involvement. Patients develop onset of unilateral or bilateral local muscle weakness, such as quadriceps, finger flexors, wrist flexors, or dorsiflexors, and then expand to other muscle groups within months or years. Selective muscle weakness is the most characteristic. About one-third of patients have facial muscle weakness, and most of the extraocular muscles are not affected. Many patients may have difficulty swallowing due to the involvement of the laryngeal muscle. On examination, the palm forearm muscle group and quadriceps atrophy with disappeared knee reflexes, and other tendon reflexes were normal at first, but may weaken with the progress of the disease. A small number of patients can be associated with cardiovascular disease.
Inclusion body myositis test
- Laboratory inspection
- Serum CK can be normal or increased several times, but does not exceed 12 times the upper limit of normal value; the red blood cell sedimentation rate is normal. Serum immunoglobulin and autoimmune indicators were normal.
- 2. Electromyography
- Prompt myogenic and neurogenic damage.
- 3. Muscle biopsy
- It shows that the muscle fibers are different in size, the atrophic muscle fibers are small round and small angles, and the muscle fibers are deteriorated. In particular, there are more muscle fibers with rimmed vacuoles, more basophilic particles, and monocytes. Infiltrate non-necrotic muscle fibers. Electron microscopy showed filamentous or myeloid inclusions under the myometrium or in the nucleus.
Inclusion body myositis diagnosis
- 1. Onset patients over 50 years of age, chronic course, weakness of the proximal and distal limbs, dysfunction and muscle atrophy, especially the weakness of the quadriceps atrophy;
- 2. Laboratory examination showed a moderate increase in serum CK levels, and electromyographic examination revealed myogenic and neurogenic damage;
- 3. Muscle biopsy showed different muscle fiber sizes, atrophic muscle fibers showed small rounds and small horns, and muscle fiber aberrations were seen, especially when more muscle fibers showed bordered vacuoles, and monocytes infiltrated non-necrotic muscle fibers. Electron microscopy showed filamentous or myeloid inclusions under the myometrium or in the nucleus.
Inclusion body myositis treatment
- At present, there is no specific treatment, such as the rapid development of the disease, and pathological suggestion of inflammatory cell infiltration, you can try glucocorticoids and immunosuppressive therapy, can also be treated with high-dose immunoglobulin intravenous drip, with certain effects.