Zebra of the Week: Inclusion body myositis

Inclusion body myositis (IBM), a type of inflammatory myopathy, is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy. Common symptoms include progressive weakness of the legs, arms, fingers, and wrists. Some people also have weakness of the facial muscles (especially muscles controlling eye closure) or dysphagia. Muscle cramping and pain are uncommon, but have been reported in some people. The underlying cause of IBM likely involves the interaction of genetic, immune-related, and environmental factors; the condition itself is not typically inherited.