Edit concept Question Editor Create issue ticket

Inclusion Body Myositis


Inclusion body myositis (IBM) is an inflammatory muscle disorder, characterized by progressive muscle weakness and wasting.


Since the disease has a gradual onset and a slow progression, the signs and symptoms are not alarming and can only be noted after a while.

The disease includes degenerative changes of the muscle tissue, primarily either the wrists or the thighs. The symptoms can be noticed by the patients when they complain of loss of grip either while walking, wearing footwear, lifting their feet or in the case of the upper extremity when holding a bag or lifting a suitcase and gripping objects which may lead to many accidental drops or slipping and falling.

70% of the patients usually experience similar symptoms involving the use of extremities. 30 to 35% patients have involvement of other muscle tissues like that of the oesophagus that leads to difficulty in swallowing. Specifically in inclusion body myositis, the other muscle tissues like cardiac muscle or skin and lungs are generally not involved unlike other myopathies.

Notable Signs:

  • History of frequent falls
  • Difficulty in getting up from a chair or from standing after lying down
  • Clumsiness while walking, tripping often or loss of footing
  • Awkwardness with the upper extremities – dropping of things from hands due to a weak grip
  • Difficulty while swallowing

Symptoms that can be observed:

  • Visible shrinking of the quadriceps due to atrophy
  • Muscle power grade weakened in the forearm
  • Muscle power grade decreased below the knees
  • Muscle power and contraction difficult around the MCP joints and weaker grip on pinching and squeezing with fingers noted during examination
Short Stature
  • The clinical features of the presented case, manifested by the onset of the disease in early childhood, delayed motor development, short stature, lordosis and joint contractures were suggestive of congenital myopathy.[ncbi.nlm.nih.gov]
  • The co-existence of these pathologic features (that is, inflammation and protein aggregation) has divided the field of sIBM research into two opposing (albeit slowly unifying) camps regarding disease pathogenesis.[ncbi.nlm.nih.gov]
Respiratory Distress
  • Because of persistent respiratory distress unresponsive to standard therapy for congestive heart failure, chronotropic insufficiency, and pulmonary hypertension, further evaluation was undertaken which revealed that diaphragmatic weakness was the etiology[ncbi.nlm.nih.gov]
  • In this study, DNA from 79 patients with sIBM was collected and the sequencing of 38 genes associated with hereditary inclusion body myopathy (IBM), myofibrillar myopathy, Emery-Dreifuss muscular dystrophy, distal myopathy, amyotrophic lateral sclerosis[ncbi.nlm.nih.gov]
  • Unlike other inflammatory myopathies, dysphagia in inclusion body myositis is steroid resistant. Management can be difficult.[ncbi.nlm.nih.gov]
  • […] myofibrillar myopathy also had sarcoplasmic TDP-43.[ncbi.nlm.nih.gov]
  • Brain 128 : 1887–1896 61 Dalakas MC (2003) Therapeutic approaches in patients with inflammatory myopathies.[doi.org]
  • EMG studies – electromyography would show all the known features of myopathy – inflammatory or non-inflammatory based on the type of Inclusion Body Myositis or Inclusion Body Myopathy.[symptoma.com]
Muscle Weakness
  • We have identified several patients with sIBM in our cohort with muscle weakness of the flexors but not the quadriceps femoris.[ncbi.nlm.nih.gov]
  • We postulate that muscle biopsy may be warranted in select patients suffering from a protracted muscle weakness.[ncbi.nlm.nih.gov]
  • However, we were unable to determine the mechanism underlying the dasatinib-associated muscle weakness.[ncbi.nlm.nih.gov]
  • The case of a 77-year-old woman with hepatitis C virus infection with a 5-year history of muscle weakness and mild disturbance of gait is reported. Steroid therapy did not improve her symptoms.[ncbi.nlm.nih.gov]
  • The unexpected appearance of myalgia during the course of painless inclusion body myositis must arouse the suspicion of an association of another inflammatory muscle disease, macrophagic myofasciitis.[ncbi.nlm.nih.gov]
  • RESULTS: sIBM patients presented with higher rates of disease- and muscle-related conditions, such as myalgia, myositis, muscle weakness, dysphagia, pneumonia, and falls.[ncbi.nlm.nih.gov]
  • Myalgia and muscle tenderness may occur in a small number of patients, usually early in the disease, and particularly in DM associated with connective tissue disorders.[accessmedicine.mhmedical.com]
  • […] a greater extent than the dominant side The most common complaint is quadriceps weakness Finger flexor and ankle dorsiflexion weakness can be noted clinically Dysphagia is a common symptom ( J Neurol 2005;252:1448 ) Generally, patients do not report myalgias[pathologyoutlines.com]
  • Other post marketing surveillance studies have reported variable ranges of the incidence of myalgia and muscle spasms [ 13 ], although muscle weakness has never been reported as an adverse reaction to dasatinib therapy.[jmedicalcasereports.com]
Proximal Muscle Weakness
  • We report a 17-year-old girl with an unusual neuromuscular disorder characterised by slowly progressive proximal muscle weakness whose muscle biopsy showed multiple ring fibres and numerous rimmed vacuoles as well as intracytoplasmic and intranuclear[ncbi.nlm.nih.gov]
  • Inclusion body myositis features a slowly progressive inflammatory myopathy characterized by progressive proximal muscle weakness in the lower extremities, followed by proximal, upper-extremity weakness and later involvement of distal muscles groups.[ncbi.nlm.nih.gov]
  • We present a case of a 76-year-old woman with systemic lupus erythematosus (SLE) who developed proximal muscle weakness of lower extremities and mild elevation of serum creatine kinase (CK) at 495 U/L.[ncbi.nlm.nih.gov]
  • IBM inclusion body myositis, NHL non-Hodgkin’s lymphoma Our patient was not receiving any drugs associated with muscle injury, but 5 years after developing non-Hodgkin’s lymphoma, gradual-onset proximal muscle weakness was noted in his legs.[jmedicalcasereports.com]
  • : Key Points • Proximal muscle weakness • May have characteristic skin involvement • • Heliotrope eyelids Gottron’s sign Polymyositis/Dermatomyositis • Diagnosis confirmed by CK levels EMG findings Muscle biopsy • • • Polymyositis/Dermatomyositis (cont[studocu.com]
Proximal Muscle Weakness of the Lower Extremity
  • Inclusion body myositis features a slowly progressive inflammatory myopathy characterized by progressive proximal muscle weakness in the lower extremities, followed by proximal, upper-extremity weakness and later involvement of distal muscles groups.[ncbi.nlm.nih.gov]
Dropping Things
  • As a result of this the symptoms noticed by you may involve dropping things, loosing grip, difficulty in holding objects or if your lower limbs are affected then tripping, falling, loss of footing, difficulty in raising your leg or getting up from a seated[symptoma.com]


Apart from the physical examination and findings mentioned above, a haemogram would reveal nothing that is diagnostic in value.

Serum Alkaline Phosphatase levels will be significantly raised.
Serum creatine kinase will be low – as low as 12 times below normal.

EMG studies – electromyography would show all the known features of myopathy – inflammatory or non-inflammatory based on the type of Inclusion Body Myositis or Inclusion Body Myopathy.

A muscle biopsy would follow an electromyography to confirm the diagnosis and look for the ‘bodies’ – clusters of degenerated cells. Also, visible would be the invasion of mono nuclear cells in the non-necrotic fibres and vacuolated muscle fibres.


In terms of treatment, more than what works, one can be sure of what doesn’t. Based on many reports in the past and clinical studies – steroids, methotrexate, azathioprine and cyclophospamide don’t elicit favourable response from the patients. Similarly immunosuppressive and immunomodulatory therapies are also a failure [4].

Some empirical therapies that may cause some relief or palliation to the patients are Coenzyme Q10, carnitine and anti-oxidants, although unfortunately these are not supported by clinical trials.

Follow up criteria for such patients [5] is the assessment of the pace and progression of the degenerative changes and to note the severity of muscle tissue damage via physical examination assessing the muscle power in terms of strength, stamina and any subsequent problems or difficulties in daily routine activities.


The prognosis for Inclusion Body Myositis is bleak but the only bright side is its slow progression and the fact that most of the times it begins after 50. With some luck most patients having the condition are able to walk with assistance while some may find themselves wheelchair ridden. Another aspect is that the disease is limited to the upper extremities or the muscle tissue it affects is not life threatening [3].


While the cause for Inclusion Body Myositis or even myopathy is not very clear, what is known is that it is an autoimmune disorder. The body attacks its own muscle tissue and in the process damages it causing degenerative changes, the exact mechanism of which is not very clear at the moment.

Even though it cannot be pinpointed to one cause, it is clear that there exists a genetic involvement. That gene can be either dominant or recessive, probably linked more to males.

Another known cause is the HIV virus, which acts only in patients already suffering from AIDS. There have been known cases of the patients having affected by the Coxsackie B virus as well.

Drug side-effect involvement has not been ruled out in cases of inclusion body myositis. There are a few drugs that are known to be trigger factors but are pending research e.g. caricaine, carbimazole, cimetidine, penicillamine and phenytoin [1].


Males have found to be suffering from Inclusion Body Myositis 2 times more than women. The onset of symptoms is usually seen after the age of 50 years but sometimes the symptoms manifest after the 3rd decade of life as well. These symptoms are subtle signs of weakness in the muscles, like the atrophy of the muscles of the forearm or thighs. The same muscular weakness may be seen in the wrist or fingers and occasionally, as dysphagia owing to the weakness of the musculature of the oesophagus [2].

Sex distribution
Age distribution


The pathophysiology of Inclusion Body Myositis involves both inflammatory as well as degenerative characteristics even though it is known to be similar to other myopathies like dermatomyositis and polymyositis. Though the exact pathogenesis is not clearly known, there are 3 main theories regarding it. One of which is that since it is an auto-immune disorder, there is a primary T-cell mediated response, which is an autoimmune reaction and this causes the muscle damage.

Another theory proposes that the degenerative process is the primary reaction and owing to some protein causes an inflammatory response as the secondary reaction. There is one more theory which claims that both the immune response degenerative changes are two separate reactions and independent of each other which maybe triggered by some external factor.


Being a genetically inherited mutation, there is no prevention available for the condition.


Inclusion Body Myositis (IBM) is the term used to signify a disorder caused due to inflammation of muscles. Its characteristic feature is progressive muscle weakness and wasting. It is a type of myopathy and can affect the blood vessels surrounding the muscles as well. Literal translation will tell us that it means inflammation of the root of the muscle.

One of the characteristics of Inclusion Body Myositis is that the muscle tissue is invaded by a number of inflammatory cells that bring along with it muscle degeneration. Later one can find ‘the bodies’ – that is the waste cells or deceased cells that collect in the tissues of the muscles.

Some rare forms of Inclusion Body Myositis which are genetic or hereditary in nature can present the same symptoms as regular IBM except for the inflammation. In such cases, since there is no inflammation the suffix ‘itis’ is not used and the nomenclature changes to myopathy – inclusion body myopathy – to signify the muscle disorder without the inflammation.

Patient Information

Inclusion Body Myositis is generally a hereditary disorder passed on more in men than women and is usually noticed only after 50 years of age. It is a disease which involves the muscle tissue but is specific only to the muscles of the wrists, upper extremities or of the legs, especially of the thighs. Occasionally it may also involve the muscle of the oesophagus.

As a result of this the symptoms noticed by you may involve dropping things, loosing grip, difficulty in holding objects or if your lower limbs are affected then tripping, falling, loss of footing, difficulty in raising your leg or getting up from a seated position.

Sometimes it may also be caused as a reaction to viruses like the HIV and Coxsackie B. It is essentially an auto-immune disorder, which means, the body cells attack their own muscle tissue. The cause of this is not well understood as is the treatment – another hazy area.

Medicines like CoQ10, carnitine and anti-oxidants may provide some relief. Good news, in a way, is that it is not fatal and has a very slow pace of progression and limits itself to these few areas, not affecting the heart or lungs like other myopathies.



  1. Karpati G, O'Ferrall EK. Sporadic inclusion body myositis: pathogenic considerations. Ann Neurol. Jan 2009;65(1):7-11
  2. Cox FM, Titulaer MJ, Sont JK, Wintzen AR, et al. A 12-year follow-up in sporadic inclusion body myositis: an end stage with major disabilities. Brain. Nov 2011;134:3167-75
  3. Lotz BP, Engel AG, Nishino H, et al. Inclusion body myositis. Observations in 40 patients. Brain. Jun 1989;112 (Pt 3):727-47
  4. Breithaupt M, Schmidt J. Update on treatment of inclusion body myositis. Curr Rheumatol Rep. May 2013;15(5):329.
  5. Hicks J. Comprehensive rehabilitative management of patients with polymyositis and dermatomyositis. In: Dalakas M, ed. Polymyositis and Dermatomyositis. Boston, Mass: Butterworth-Heinemann; 1988:293-318.

Ask Question

5000 Characters left Format the text using: # Heading, **bold**, _italic_. HTML code is not allowed.
By publishing this question you agree to the TOS and Privacy policy.
• Use a precise title for your question.
• Ask a specific question and provide age, sex, symptoms, type and duration of treatment.
• Respect your own and other people's privacy, never post full names or contact information.
• Inappropriate questions will be deleted.
• In urgent cases contact a physician, visit a hospital or call an emergency service!
Last updated: 2019-07-11 20:43