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.
Symptoms that can be observed:
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 .
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  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 .
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.
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 .
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 .
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.
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.