Today is World Myositis Day!
Myositis is an inflammatory autoimmune condition that can cause muscles to become weak and painful. Idiopathic inflammatory myopathies are an umbrella term for the different types of myositis. These autoimmune conditions mean the body attacks its own muscles, connective tissue, blood vessels, skin, lungs, and other organs. This often occurs together with other symptoms, such as muscle swelling, pain, fatigue, difficulty moving limbs or lifting arms, increased falls, trouble swallowing, and others.
Myositis is considered a relatively rare condition (14/100,000), with a peak incidence in 50-to-79 years and more cases in females than males.
The four main types of idiopathic inflammatory myopathy are:
Polymyositis, which affects skeletal muscles (the type involved in body movement) on both sides of the body.
Dermatomyositis, which affects the skin and the muscles. Its symptoms are generally a skin rash and progressive muscle weakness.
Inclusion body myositis is the most common inflammatory muscle condition in older adults. It is characterised by slow, progressive muscle weakness and muscle shrinking and loss of muscle of both proximal muscles (located on or close to the torso) and distal muscles (close to hands or feet).
Necrotising autoimmune myopathy, which is characterised by signs of cell death in the muscles, leading to fatigue and weakness especially in the proximal muscles (forearms, thighs, hips, shoulders, neck, back).
Diagnosis can be challenging due to the heterogeneity of myositis (different gene mutations cause the same condition) and is usually based on a combination of characteristic clinical signs and symptoms as well as laboratory, imaging, and muscle biopsy findings. It is still unclear what causes myositis, but some scientists believe certain individuals have a genetic predisposition to developing an autoimmune condition, which is activated by an environmental exposure to some trigger, such as infection, virus, toxin, and others.
Research is ongoing and there are some positive developments in myositis with more knowledge and advancements in biomarkers, diagnostic imaging and novel agents such as IVIG and the medication, tofacitinib.
Myositis research news
They are several clinical trials happening worldwide related to types of idiopathic inflammatory myopathy. They range from early pre-clinical stage to phase 3. The Myositis Association has listed current clinical trials on their page. Click on the link for more details. https://www.myositis.org/research/clinical-trials/clinical-drug-trials/
Webinars
The Myositis Association has a library of webinars that are available to view here