Inclusion Body Myositis

Inclusion body myositis, also known as IBM, is is an inflammatory muscle disorder that causes progressive weakness and inflammation in muscles throughout the body. Over time, the muscle weakness progresses and individuals may experience difficulty swallowing, frequent falls and weakness in the extremities. IBM commonly affects individuals over the age of 50 and is more prevalent in men than women.

Symptoms of Inclusion Body Myositis

The main symptom of IBM is muscle weakness that often progresses slowly over time. Inclusion body myositis may be initially characterized by episodes of frequent falls, tripping, and difficulty climbing stairs. Additional symptoms that may develop include:

  • Weakness in the wrists and fingers
  • Difficulty gripping items
  • Atrophy and weakness in the forearms and thigh muscles
  • Difficulty swallowing

Causes of Inclusion Body Myositis

The exact cause of inclusion body myositis is unknown, however one theory suggests that it may be hereditary. Research also suggests that it may be an autoimmune disorder, where the body's own immune system is destroying the healthy tissue and muscle within the body. This autoimmune disorder may be triggered by a virus that in turn causes inclusion body myositis.

Diagnosis of Inclusion Body Myositis

IBM may be diagnosed after an evaluation of the patient's medical history and a full physical examination. Additional tests may include:

  • Blood tests
  • Electromyogram
  • MRI scan
  • Nerve conduction velocity test

A muscle biopsy may also be performed to examine the strength and health of the affected muscles. These tests may also be used to rule out any underlying disorders that may mimic the symptoms of IBM.

Treatment of Inclusion Body Myositis

There is no cure currently available for IBM and effective treatment approaches can vary between patients. The methods of treatment are not always completely successful. IBM is sometimes treated with drugs that suppress the immune system, however, these treatments are not always effective. Corticosteroid medication may also be prescribed to control inflammation, ease pain, and increase muscle strength. Intravenous immunoglobulin therapy may be administered to IBM patients that are experiencing swallowing problems. Physical therapy may also be effective in increasing mobility and improving physical activity and is an important part of an IBM treatment plan.

Additional Resources