Myositis is a group of rare conditions where the body’s immune system turns against itself and destroys healthy muscle tissue instead of building new muscle tissue.

Understanding Myositis. Thank you to Civic Solutions Inc, Queensland Myositis patients and students from Griffith Film School for helping to create this video.

In everyday life, most people have experienced muscle tissue inflammation in the form of swelling around wounds and muscle and joint injuries. But, with the conditions known collectively as Myositis, the inflammation is within the muscle tissue as a chronic autoimmune response.

The seriousness of these diseases lies in the fact that the body’s inflammatory response is turned against us causing our autoimmune system to attack and destroy our own muscle tissue.

Once gone the muscle cannot be regenerated (although there are research studies working on this) and over time this can result in a progressive and cumulative loss of muscle that leads to a state of weakness and disability.

Myositis is sometimes misdiagnosed as motor neurone disease (MND). While it shares many of the severe impacts of MND, it has a relatively low public profile. That’s why we are dedicated to raising awareness about Myositis to help people get diagnosed earlier which could significantly improve their quality of life.

While symptoms may vary, the first sign of trouble is usually weakened thigh muscles making it hard to:

  • stand up from a chair
  • get up from the floor
  • walk any distance
  • go up the stairs
  • get off the toilet.

Many other muscles can also be impacted like:

  • the heart
  • lungs
  • swallowing muscles
  • hands and fingers
  • lower legs (causing foot drop).

Other symptoms may include:

  • a red or purple coloured rash or other skin changes on the eyelids, elbows, knees, chest, back, fingers and knuckles (refer to the Dermatomyositis page for more information)
  • the presence of certain antibodies in the blood. Antibodies are proteins made by the immune system and can indicate an autoimmune condition.
  • pain
  • fatigue
  • trouble swallowing
  • shortness of breath
  • lung disease
  • fevers
  • weight loss.

People living with Myositis often have difficulty walking up stairs, rising from a seated position, turning over in bed, getting off the toilet, raising their arms over their head and grasping items with their hands, and many become prone to unexpected falls.

There are some symptoms more commonly associated with specific forms of the disease. Learn more below about some of the types of Myositis. (see below)

Symptoms can appear gradually, over a period of months or years or may develop rapidly within days or weeks. There have been instances of remission with some types of Myositis (see below).

In the case of Necrotizing Myositis and some rare forms of Dermatomyositis, urgent medical care is required due to the aggressive nature of the attack on the muscles and other organs such as lungs putting lives at risk.

Generally, Myositis can cause significant muscle loss with comparable decline in strength, dexterity and mobility over time. In extreme cases, Myositis can be fatal when the heart and lung muscles are involved.

There are a number of different types of Myositis including:

Learn more about the symptoms, diagnostic process, treatment options and self-care tips for each of the different types of Myositis. Click the links above or by navigating to these pages under ‘Myositis’ on the main menu bar.

Myositis is typically diagnosed through a range of blood tests (including the Myositis panel blood test) and a muscle biopsy. The attached research article (below) reviews the types of muscle biopsies currently performed.

In all countries that collect comprehensive disease statistics Myositis falls within the definition of being a rare disease.

Based on a review of 46 existing studies published between 1966­–2013, researchers estimate that the global incidence of inflammatory myopathies (Myositis) was at 7 to 8 people per 1,000,000 of population, per year.

The juvenile form, defined as 0 to 18 years of age, had an estimated incidence of 2 to 3 young people per 1,000,000 of population, per year.

The data above is from a 2015 study published in Rheumatology, the official journal of the British Society for Rheumatology and is the first systematic review of the scientific literature looking into the global extent of Myositis.

The underlying cause of all the inflammatory muscle diseases is unknown. They are classified as autoimmune diseases because the person’s immune system is attacking their own tissue.

For people living with Inclusion Body Myositis (IBM), there may also be degenerative processes causing muscle inflammation in addition to autoimmunity. 

In rare cases, there may be drug interactions/side effects, bacterial, fungal, parasitic or viral involvement eg. Necrotizing Myositis.

Generally, Myositis is not thought to be an inheritable genetic condition. However, research indicates that genetic factors may make some people more vulnerable to developing IBM.

Seek medical advice

If you’re experiencing Myositis symptoms or have any concerns about your overall health and wellbeing, it’s important to speak to your GP or health professional.

If you are very weak, in extreme pain or feeling unusually unwell, urgent medical care may be required due to the aggressive nature of the attack which can occur on the muscles putting limbs or even our lives at risk.

Because of its rare nature, some health professionals are unfamiliar with Myositis, For the assistance of our members, we have put together a panel of medical and allied health professionals who have experience in advising people living with Myositis. It’s one of many membership benefits we offer. 

The information above is intended as a general guide to help you understand Myositis. It is not provided as medical advice or intended as a substitute for your practitioner’s advice.

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