What is the difference between polymyositis and myositis

It is characterized by a rash that appears on the eyelids, cheeks, nose, back, upper chest, elbows, knees, and knuckles. Muscle weakness often comes later. Polymyositis Polymyositis occurs in people over the age of 20, affecting more women than men.

It is characterized by muscle weakness that begins in the trunk neck, hips, back and shoulders and worsens over time. Necrotizing Myopathy Also called necrotizing autoimmune myopathy or immune-mediated necrotizing myopathy, necrotizing myopathy NM is a newly defined form of myositis characterized by increased evidence of muscle cell death necrosis.

It was once grouped under the polymyositis diagnosis, but is now considered separate. Juvenile Myositis Found in children under the age of 18, juvenile myositis JM is characterized by muscle weakness in the neck, shoulders, back, and torso. Juvenile dermatomyositis also has a red, patchy skin rash. As is the case for many rare diseases, these types of myositis can be difficult to diagnose, often requiring extensive testing and a muscle and skin biopsy.

The muscles most severely affected are typically those closest to the trunk or torso. This results in weakness that can be severe. Some patients with polymyositis also have lung involvement, which can cause difficulty breathing. The incidence of polymyositis increases with age, with the highest rates being seen in the and year old age groups.

The effects can happen slowly over 10 to 15 years. It affects more men than women, and generally starts once people are over the age of The key difference in inclusion body myositis compared to other types of myositis is that as well as inflammation in the muscles, there is also a build-up of protein. These tiny clumps of protein can only be seen with special microscopes. They might not be seen clearly in the early stages of the condition. And so it can be difficult to tell the difference between polymyositis and inclusion body myositis.

Anti-synthetase syndrome is a condition where several parts of the body are affected by inflammation. It can affect the muscles, and elsewhere, such as the lungs and skin. This lung condition can potentially be serious, which is why prompt medical treatment is important. Early symptoms can be a dry cough, which can occur before skin and muscle symptoms.

In this condition the fingers and toes change colour when cold. They may turn white, then blue and feel very cold to touch. When they warm up again, the fingers and toes may go red and start to throb or swell. Some people with this condition have in the past incorrectly been told that they have polymyositis or dermatomyositis. It has some similar symptoms, but is now being classed as a separate condition.

This type of myositis has been discovered more recently. It causes muscle cells to rapidly die in a process called necrosis. Weakness is usually very severe and people with this condition will often struggle to walk and use their arms.

In extremely rare cases, this condition can be triggered by statin medication. Infectious or post-infectious reactive myositis can occur during and after some viral infections. Even after the virus has gone, the immune system may cause inflammation in some parts of the body for a few months.

Symptoms are similar to those of polymyositis, such as muscle pain and weakness. Usually, the condition is mild and can settle without treatment. Drug-induced myopathies can sometimes appear like myositis. Usually, stopping this drug treatment leads to improvement in symptoms. Occasionally, the symptoms can last after the drug treatment has been stopped and people can develop myositis. In most cases the pain and feelings of being unwell are eased with drugs.

Even in severe cases most people with myositis eventually respond to treatment. Muscle strength can take longer to get back to normal. Once myositis is controlled with treatment, exercises can also help to improve muscle strength. Although people can make a good recovery, some never regain their original muscle strength or function. We are still doing research into why this is the case. Occasionally, myositis can affect breathing and swallowing.

This may occur at the start of severe cases when the muscles used for these important tasks become weak. If there is inflammation in the lungs this can cause scarring, which can affect how the lungs work. Lung and heart conditions can cause long-term breathlessness.

Children with dermatomyositis may develop painful deposits of the mineral calcium in damaged muscles. These deposits, combined with loss of mobility, can occasionally result in permanently rigid joints, which are called contractures. Polymyositis occasionally occurs in patients who have other autoimmune conditions such as rheumatoid arthritis , lupus or scleroderma.

On rare occasions, myositis can be associated with cancer. There is no autoantibody test that can prove for certain you have myositis, but there are tests that can be helpful in making a diagnosis. One of these is the anti-nuclear antibody test ANA.

This is a test to see if your blood has antibodies that attack the central part of a cell called the nucleus. Other autoantibody tests include ENA extractable nuclear antigens and the anti-Jo-1 test. These tests are sometimes positive in people with myositis.