What is Inclusion Body Myositis?

Inclusion body myositis is a degenerative disorder that causes inflammation and weakening of muscle tissue. The disorder can be hereditary or sporadic, meaning it can be passed down genetically and present early in life, or appear unexpectedly in individuals over the age of 50. Muscle fibers tend to deteriorate over months or years and often lead to difficulties standing, walking, grasping objects, and swallowing. There is no cure or reliable medical treatment for inclusion body myositis, but regular physical therapy sessions can help ease symptoms and slow the progression of muscle problems.

The causes of inclusion body myositis are not well understood, but medical researchers believe the disorder may be the result of an abnormal immune system response to a retrovirus. Research suggests that inflammation and weakness are primarily caused by irregular T cells, specialized white blood cells that are essential in fighting off viruses. In a person with inclusion body myositis, T cells are cloned in huge numbers and mistakenly attack healthy muscle fibers.

A individual with inclusion body myositis usually experiences progressive muscle weakness in many parts of the body, especially the hands, forearms, legs, and throat. Weakened muscles can make it difficult to grip objects with the fingers and control the legs when walking. When the disorder affects the throat and face, people have trouble swallowing food and speaking clearly. As the condition worsens, many people are unable to move around without the aid of a walker or a wheelchair. Muscle weakness is often accompanied by constant dull aches and occasional sharp pains.

Doctors usually diagnose the condition by conducting physical examinations, taking magnetic resonance imaging (MRI) scans of muscles, and extracting samples of muscle tissue for laboratory analysis. A physician will look for signs of inflammation and degeneration in MRI and muscle biopsy results. Clinical laboratory specialists count the number of T cells in tissue samples in order to rule out other causes of muscle problems.

There is no known cure for inclusion body myositis, and doctors cannot generally treat the condition with medicines or hormone therapy. Most patients who are diagnosed with the disorder are scheduled for physical rehabilitation therapy sessions with professional trainers. Physical therapists can help people strengthen their leg and arm muscles through custom exercise and weightlifting routines. In addition, trainers teach patients how to reduce their risks of falling and other accidents by fitting them with walkers or suggesting they admit themselves into assisted living facilities.