Inclusion body myositis

Sporadic inclusion body myositis ( sporadic inclusion body myositis; sIBM ) belongs to the group of inflammatory muscle diseases. The term " inclusion body myositis " was coined in 1971. However, in 1967, described IBM -like changes at a suitable clinic in muscle tissue of patients with polymyositis. In addition to the sporadic form ( sIBM ) there is also a hereditary variant ( HIBM ), in which there is a non-inflammatory muscle disease.

Epidemiology, symptomatology and course

The frequency of sIBM is estimated at 4.3 to 14.9 per million. However, in patients older than 50 years it rises to as much as 51.3 per million. The average age of onset is around 55 years, but there are also cases in which the disease manifests itself to the 30 or 80 years of age. Approximately three-quarters of those affected are male. The sIBM is a chronic progressive, inflammatory muscle disease that leads to muscle weakness and wasting hull near and distant muscles. At the beginning of the disease the quadriceps femoris and the deep finger flexors are often involved, which patients fall very light and fine motor activities can not run. In the course of the muscle weakness continues to grow, so that the patients are confined within a few years to a wheelchair. Through participation of the swallowing muscles occur in many cases on swallowing.

Histopathology

In the muscle of sIBM patients, typical myopathic changes, including fiber caliber variations, central nuclei and a connective tissue remodeling are found. Other characteristics include inclusion bodies and vacuoles within the muscle fibers. Specifically, there is an accumulation of molecules, such as the degeneration of the Alzheimer's disease beta-amyloid known. In addition to these, there are also degenerative regenerating fibers. Frequently occur inflammatory infiltrates, which are primarily about cytotoxic T cells change morphologically inconspicuous muscle fibers. A small percentage of fibers is necrotic.

Pathogenesis

The etiology and genesis of sIBM is complex yet not fully understood or understood. There are currently discussing inflammatory, degenerative and cell stress -associated pathomechanisms. Recent studies confirmed the assumption of a relationship between inflammation and degeneration as well as degeneration and cell stress. The exact mechanisms that lie behind it are, however, still not clear enough. Furthermore, it is suspected a connection with autophagic processes.

Diagnostics

The diagnosis of sIBM is very comprehensive, which is why there are often delays in diagnosis and quality assurance. Current criteria include a detailed doctor-patient conversation, as well as a thorough medical examination. Furthermore, blood tests are performed to determine the amount of specific proteins, such as creatine kinase. The function of the nerve and muscle are analyzed using electrophysiological methods. Also, a muscle sample was taken for histological examination.

Therapy

To date, there is no effective therapy that cures the disease. Due to the presence of inflammatory infiltrates in muscle immunosuppressive or immunomodulatory sIBM - drugs have been tested in recent years in numerous studies. In individual cases could be stopped with immunoglobulins of disease progression. The administration of the glucocorticoid prednisolone, the folic acid analogue, methotrexate or known from multiple sclerosis therapy glycoprotein interferon - β 1a proved to be ineffective in the treatment of IBM. However, few successes have been achieved. Studies from 2009 showed that the monoclonal antibody alemtuzumab ( CAMPATH 1-H), which causes a reduction of peripheral lymphocytes in the blood, resulting in a temporary slowing of disease progression. However, the use is limited due to side effects. The suppression of β -amyloid aggregate formation is the subject of scientific research. In addition to drug therapy, supportive measures are applied, especially targeted physiotherapy.