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What is Inclusion body myositis (IBM)

Inclusion body myositis (IBM) is one of a group of autoimmune related muscle diseases known as the inflammatory myopathies, which are characterized by chronic, progressive muscle inflammation accompanied by muscle weakness. The onset of muscle weakness in IBM is generally gradual (over months or years) and affects both proximal (close to the trunk of the body) and distal (further away from the trunk) muscles. Muscle weakness may affect only one side of the body. Falling and tripping are usually the first noticeable symptoms of IBM. For some individuals, the disorder begins with weakness in the wrists and fingers that causes difficulty with pinching, buttoning, and gripping objects. There may be weakness of the wrist and finger muscles and atrophy (thinning or loss of muscle bulk) of the forearm muscles and quadricep muscles in the legs. Difficulty swallowing occurs in approximately half of IBM cases. Symptoms of the disease usually begin after the age of 50, although the disease can occur earlier. IBM occurs more frequently in men than in women. There is no cure for IBM.

Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy (wasting). It is a type of inflammatory myopathy. IBM develops in adulthood, usually after age 50. The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and wrists. Some people also have weakness of the facial muscles (especially muscles controlling eye closure), or difficulty swallowing (dysphagia). Muscle cramping and pain are uncommon, but have been reported in some people.[1][2]

Most people with IBM progress to disability over a period of years. In general, the older a person is when IBM begins, the more rapid the progression of the condition. Most people need assistance with basic daily activities within 15 years, and some people will need to use a wheelchair. Lifespan is thought to be normal, but severe complications (e.g. aspiration pneumonia) can lead to loss of life.[3]

The underlying cause of IBM is poorly understood and likely involves the interaction of genetic, immune-related, and environmental factors. Some people may have a genetic predisposition to developing IBM, but the condition itself typically is not inherited.[2]

There is currently no cure for IBM.[2] The primary goal of management is to optimize muscle strength and function.[3] Management may include exercise, fall prevention, physical therapy, occupational therapy, and speech therapy (for dysphagia). There is limited evidence that a small proportion of patients may benefit from drugs that suppress the immune system (particularly those with underlying autoimmune disorders), but this therapy is otherwise typically not recommended.[3]

This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
https://rarediseases.info.nih.gov/diseases/3896/inclusion-body-myositis

Related Autoimmune Patient Groups

Myositis Assc
The Myositis Association (TMA)

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