Inclusion Body Myositis - All About a Painless Disease

Introduction

Inclusion body myositis is a disease of the muscle that is degenerative (progressive damage and decreased function of any organ or tissue present in the body). It is one of the most common muscle diseases observed in individuals above the age of 50. The word “myo” means muscle, and “itis” means swelling or inflammation. Hence myositis is an inflammatory muscle disease.

What Is Inclusion Body Myositis (IBM)?

Inclusion body myositis is a muscle disorder that shows features like inflammation (swelling) of the muscles followed by weakness and muscle atrophy (wasting away of muscles). The muscles in patients with inclusion body myositis get filled with inclusion bodies. These bodies contain discarded cellular materials of dead tissues. In inclusion body myositis, the first set of muscles to get affected are the muscles of the fingers, wrist, and front part of the thighs. The muscles which are used to lift the front part of the feet are also affected.

What Are the Causes of Inclusion Body Myositis (IBM)?

In most cases, the exact cause of the inclusion body myositis is not known. However, researchers have linked IBM to the following causes. They are as follows:

• Autoimmune Processes: A person’s immune system (organs and processes in a person’s body which help in the resistance of toxic substances and infections) fights against the muscles of their own body and leads to muscle destruction.

• Viruses: Some researchers believe that few viruses are linked to inclusion body myositis. People infected with viruses like HIV (human immunodeficiency virus), and coxsackie virus (responsible for hand, foot, and mouth disease which involves rashes on hands, feet, and mouth) are prone to get inclusion body myositis.

• Drug Exposure: There are few cases of inclusion body myositis which has been linked to exposure to certain medications. The drugs used in the treatment of chronic myeloid leukemia (cancer that begins in the blood-forming cells of the bone marrow), antivirals used in the treatment of HIV- articaine (a drug used to decrease cholesterol levels), and carticaine (used for giving anesthesia locally) are few of the examples.

• Old Age: Some researchers believe that inclusion of body myositis is due to old age. It happens when the aging muscle fibers become unable to fight against the destructive chemicals.

What Are the Symptoms of Inclusion Body Myositis (IBM)?

In inclusion body myositis, the weakening of muscles occurs slowly over a period which can vary from months to years. The symptoms commonly observed in patients are:

• Weakness of the muscles of the wrist and fingers that leads to difficulty in gripping, like trouble in opening a jar.

• Shrinking of the muscles of the forearm (a portion of the hand extending from the elbow to the wrist or fingertips).

• Weakness of the muscles located in the front portion of the thighs.

• Weakness of the muscles of the esophagus (a tube that carries food from the throat into the stomach). This can lead to difficulty in swallowing.

• Weakness of the muscles of the knees.

• Difficulty in getting up after being seated on a chair and climbing stairs due to the weakening of the pelvic girdle (group of bones that connects the upper body with the legs).

• Mild muscle pains which occur repeatedly.

• Trouble in raising the front part of the foot.

• Tripping and falling frequently.

• Reduced ability to walk and reduced dexterity (performing tasks with hands).

• Difficulty in combing hair and reaching overhead shelves due to weakening of the shoulder muscles.

How to Diagnose Inclusion Body Myositis?

• Medical History and Physical Examination: The doctor takes elaborate notes of the patient’s personal history, and family medical history and carries out a detailed physical examination. It helps to find out the pattern of muscle weakness in a person.

• Blood Tests: The doctor asks the patient to carry out a blood test to find out the levels of creatine kinase (CK). It is an enzyme (a substance produced by a living organism to carry out a biochemical reaction) that leaks out from the muscle fibers when the muscles undergo damage. In patients with inclusion body myositis, there is a slight elevation in the enzyme levels. The antibodies (proteins produced by the immune system of a person having the disease) are also checked.

• Electromyography: An electromyogram (EMG) is a test that is performed by inserting small needles into the muscles. This is done to check the electrical activity of the muscles during rest and when a person performs any activity using the muscles. The unique pattern of electrical activity helps to differentiate inclusion body myositis from other muscle diseases.

• Nerve Conduction Velocity Test: This test measures the speed and strength of a nerve impulse (an electrical signal that travels from a nerve in response to a stimulus). This is carried out to find out if any interruptions are present in the nerve signals.

• Biopsy: A sample of tissue is removed from the affected muscle and observed under a microscope in the laboratory. The muscle cells of persons with inclusion body myositis show empty round spaces which contain clumps of discarded cellular material which are abnormal proteins. These clumps are known as inclusion bodies which are the characteristic feature of this disease.

How Is Inclusion Body Myositis Treated?

There is no specific treatment to get rid of inclusion body myositis. However, the following treatment options are carried out to treat the symptoms. They are as follows:

• Medical Management: Drugs that suppress the immune system of the patient have been tried, but it is not effective. Even though certain medicines that treat swelling and alter the immune system are effective, many clinicians feel that the side effects of these medicines outweigh their benefits.

• Physical Therapy and Occupational Therapy: Physical therapy helps to maintain the strength and movement of joints. Occupational therapy helps to make daily activities easier and prevent fall injuries. It can be helpful in the movement and functioning of the joints in patients with difficulty in walking and hand movements. Aerobics and muscle strengthening programs are highly recommended. A custom exercise plan is mostly formulated by a neurologist specialized in myositis.

• Speech Language Therapy: Patients with difficulty in swallowing are evaluated by a speech therapist. Techniques to reduce the risk of aspiration (anything entering a person’s lungs or airways accidentally) are taught by the therapist.

• Other Measures: In severe cases, where the patient has difficulty walking, a cane or wheelchair may be required for long distances.

• Psychological Measures: A rehabilitation psychologist helps to improve the mental state and quality of life of persons with disabilities. They help to manage the psychological aspects of living in patients with inclusion body myositis.

Conclusion

Although inclusion body myositis does not have a definitive treatment, it does not affect the life expectancy of a person. Early diagnosis and prompt treatment reduce the severity of the disease. Follow-up visits are necessary to find out the progress of the disease and the need for symptom control.