Inclusion Body Myositis (IBM)

Inclusion body myositis (IBM) facts*

*Inclusion body myositis (IBM) facts medical author: William C. Shiel Jr., MD, FACP, FACR

  • Inclusion body myositis is a muscle disease that gradually worsens.
  • Inclusion body myositis affects adults typically with onset after 50 years of age.
  • Symptoms of inclusion body myositis include progressive weakness and atrophy (wasting) of the muscles of the arms, legs, fingers, and forearms.
  • The cause of inclusion body myositis is not known.
  • There is no cure for inclusion body myositis and the treatment is supportive.
  • Treatment for patients with inclusion body myositis often includes physical therapy with strengthening and fall prevention.


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.

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.

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.

There is currently no cure for IBM. The primary goal of management is to optimize muscle strength and function. 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.


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This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO). The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly.

Medical TermsOther Names
80%-99% of people have these symptoms
AutoimmunityAutoimmune disease
Autoimmune disorder
Elevated serum creatine kinaseElevated blood creatine phosphokinase
Elevated circulating creatine phosphokinase
Elevated creatine kinase
Elevated serum CPK
Elevated serum creatine phosphokinase
High serum creatine kinase
Increased CPK
Increased creatine kinase
Increased creatine phosphokinase
Increased serum CK
Increased serum creatine kinase
Increased serum creatine phosphokinase
EMG abnormality
Inflammatory myopathy
Quadriceps muscle weaknessQuadriceps weakness
Ragged-red muscle fibers
Rimmed vacuoles
Skeletal muscle atrophyMuscle degeneration
Muscle wasting
30%-79% of people have these symptoms
Feeding difficulties in infancy
Reduced tendon reflexes
5%-29% of people have these symptoms
MyalgiaMuscle ache
Muscle pain
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
Distal muscle weaknessWeakness of outermost muscles
DysphagiaPoor swallowing
Swallowing difficulties
Swallowing difficulty
HyporeflexiaDecreased reflex response
Decreased reflexes
Proximal muscle weaknessWeakness in muscles of upper arms and upper legs
Slow progressionSigns and symptoms worsen slowly with time
SporadicNo previous family history


Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

The Centers for Mendelian Genomics program is working to discover the causes of rare genetic disorders. For more information about applying to the research study, please visit their website. lists trials that are related to inclusion body myositis. Click on the link to go to to read descriptions of these studies.

Talk with a trusted health care provider before choosing to participate in any clinical study.

Patient Registry

A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with inclusion body myositis. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

Registries for Inclusion body myositis:
The Inclusion Body Myositis Disease Registry at Yale


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM)
2621 Superior Drive NW
Rochester, MN 55901
Telephone: 507-288-0100
Fax: 507-288-1225
E-mail: [email protected]

Cure IBM

Muscular Dystrophy Association (MDA)
222 S Riverside Plaza
Suite 1500
Chicago, IL 60606
Toll-free: 1-833-275-6321 (Helpline)
E-mail: [email protected]

Myositis Support and Understanding
9125 N. Old State Road
Lincoln, DE 19960
Toll-free: 1-888-MYO-RARE (696-7273)
Telephone: +1-302-339-3241
E-mail: [email protected]

Myositis UK
146 Newtown Road
SO19 9HR
United Kingdom
Telephone: 023 8044 9708
E-mail: [email protected]

The Myositis Association (TMA)
1940 Duke Street
Suite 200
Alexandria, VA 22314
Toll-free: 1-800-821-7356
Telephone: +1-703-299-4850
Fax: +1-703-535-6752
E-mail: [email protected]

Organizations Providing General Support
American Autoimmune Related Diseases Association (AARDA)
22100 Gratiot Avenue
Eastpointe, MI 48021
Toll-free: 800-598-4668
Telephone: 586-776-3900
Fax: 586-776-3903
E-mail: [email protected]

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United States. National Institutes of Health. National Center for Advancing Translational Sciences. "Inclusion body myositis." May 1, 2019. <>

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