The risk of developing polymyositis increases with age and shows the highest rates of incidence between the ages of 35 to 44 and 55 to 64. Women are also twice as likely as men to develop polymyositis.
For those of us with chronic autoimmune diseases, such as the idiopathic inflammatory myopathies, generally referred to as myositis, stress can be even more damaging. It has been shown that stress can diminish our immune system, cause disease, and increase inflammation.
It's more common in women and tends to affect people aged 30 to 60.
Myositis can affect people of any age, including children. The main muscles to be affected are around the shoulders, hips and thighs. Having myositis can also lead to other parts of the body being affected, such as the skin, lungs or heart.
Infection. Viral infections are the most common infections causing myositis. Rarely, bacteria, fungi, or other organisms can cause myositis as well. Viruses or bacteria may invade muscle tissue directly, or release substances that damage muscle fibers.
Among metabolic myopathies that can mimic myositis are disorders of carbohydrate metabolism such as McArdle's disease, 6-phosphofructokinase deficiency, and Pompe's disease (adult acid maltase deficiency); disorders of lipid metabolism such as carnitine deficiency and carnitine palmitoyltransferase 2 (CPT2) deficiency; ...
Inclusion body myositis usually affects people over age 50. It may go undiagnosed for a long time before the symptoms of muscle weakness manifests. Juvenile myositis affects children between ages 5 and 15. It often causes a rash as well as fatigue and muscle weakness.
According to The Myositis Association, more than 95% of these patients are still alive more than five years after diagnosis. Many experience only one period of acute illness in their lifetime, while others struggle with symptoms for years.
Nevertheless, myositis is a serious illness that, in most cases, needs to be treated aggressively. With inadequate or no treatment, myositis can cause significant disability and even death. There is no cure for any of the forms of myositis.
Myositis frequently occurs with other conditions, which share similar symptoms or affected organs. For example, people with myositis may have other autoimmune conditions like lupus or rheumatoid arthritis. They can also experience Raynaud's disease (this is a blanching of the fingers when exposed to the cold).
Many people dismiss the early signs of myositis, including healthcare workers, because it's similar to other conditions and the rare disease is relatively unknown. About 75,000 U.S. residents live with myositis, which has no known cure.
Symptoms of Autoimmune Myositis
Muscle weakness may start slowly or suddenly and may worsen for weeks or months.
These symptoms usually develop gradually — over a period of months and, sometimes, years.
These symptoms usually begin several weeks after a muscle injury, especially a bruise. Drug-induced myositis. Symptoms include muscle soreness, pain and weakness. These symptoms usually begin soon after a person starts taking a new drug or a combination of drugs.
COVID-19-induced myositis may vary in presentation, ranging from frank muscle weakness to typical dermatomyositis replete with classic rashes, or mere back pain with muscle disease on MRI. Most patients test positive for COVID-19 on initial presentation with most reported being males aged 33–87.
Three stages of myositis ossificans: early, intermediate, and mature. Each stage has a unique clinical, radiographic, and histologic appearance.
Exercise and physical therapy are important parts of standard myositis treatment plans. Physical exercise has been shown to reduce inflammation, reduce fatigue, increase stamina, and build muscle, even in patients with myositis.
After a careful history and physical exam to document the pattern of weakness in muscles, a doctor who suspects myositis likely will order a blood test to check the level of creatine kinase (CK), an enzyme that leaks out of muscle fibers when the fibers are being damaged. In PM, the CK level is usually very high.
Muscle and skin biopsy are often the most definitive way to diagnose myositis diseases. Small samples of muscle tissue show abnormalities in muscles, including inflammation, damage, and abnormal proteins. For those with skin symptoms, doctors often biopsy a bit of skin to examine for characteristic abnormalities.
Radiographic features. MRI is the gold standard modality for non-invasive evaluation of myositis, which shows a classic edema signal pattern (high T2WI and STIR signal) in affected muscles.
Myositis means inflammation of the muscles that you use to move your body. An injury, infection, or autoimmune disease can cause it. Two specific kinds are polymyositis and dermatomyositis. Polymyositis causes muscle weakness, usually in the muscles closest to the trunk of your body.
This inflammation usually results in muscle fatigue and weakness, frequent falling, swelling of the feet and legs, and muscular and joint pain. Early symptoms in patients with myositis include: Difficulty standing up from a seated position. Difficulty climbing stairs.