This is one of a group of muscle conditions that is known as inflammatory myopathies that is characterized by the progressive muscle inflammation and muscle weakness. This rare disease affects the muscle cells although not all muscles are impacted during the course of the illness. The symptoms may appear after the age of 50 but the disease can develop as early as the 30s. The onset of symptoms and how it affects the individual can be quite variable between different cases. There are various types of myositis such as polymyositis, dermatomyositis and juvenile forms of myositis. There are two main types of inclusion body myositis. The common type is the spontaneous inclusion body myositis and the second one is the hereditary inclusion body myopathy.
Causes
Although the exact cause of the condition is not known, research suggests various theories. One of them is that as the immune system is involved in the process of damaging the muscle cells which can cause protein abnormalities. Another theory suggests that the protein abnormalities can damage the muscle cells which can cause the immune system abnormalities.
Symptoms
The affected individual can experience muscle weakness that can progress slowly over several months or years. The symptoms include weakness in the thighs, wrists and the fingers. The affected individual may also have difficulty with climbing stairs, falling frequently, a problem with rising from a seated position, have a weakened hand grip and a foot that appears to drop when walking causing tripping. The weakness of the throat muscles can cause difficulty with swallowing and chocking.
Diagnosis
The diagnosis is based on a detailed clinical evaluation, assessing the individual’s history and with various specialized tests. An electromyography involves a process where the electrical activity of the muscles is recorded that illustrates how well the muscle reacts to the nerves. This test can determine if the muscle weakness is caused by the muscle or the nerves. A blood test can also help detect the elevated levels of creatine kinase which occurs when the muscle becomes damaged. However, this cannot confirm the diagnosis but is only used to determine inflammation or the damage of the muscles. A muscle biopsy may be required to detect the characteristic changes of the condition.
Treatment
There is neither cure for the disease nor any standard treatment procedures available. The treatment can include medications to suppress the immune system although most of the patients don’t respond well to these treatments. Evidence suggests that in some cases an intravenous immunoglobulin may have a short-lasting beneficial effect on the affected individual. The specific treatment options include physical therapy to improve the muscle strength and the use of assistive devices such as wheelchairs or walkers to help with walking.
References
https://rarediseases.org/rare-diseases/sporadic-inclusion-body-myositis/
https://www.hopkinsmyositis.org/myositis/inclusion-body-myositis/
http://www.myositis.org/learn-about-myositis/types-of-myositis/inclusion-body-myositis
https://www.ninds.nih.gov/Disorders/All-Disorders/Inclusion-Body-Myositis-Information-Page
http://www.aanem.org/Patients/Disorders/Inclusion-Body-Myositis
