inclusion body myositis

• most common in the elderly
• equal sex incidence

• sporadic idiopathic disease (very rarely familial)
• misdiagnosed as steroid-resistant polymyositis

symptoms

• presents as a painless slowly progressive proximal myopathy
• may cause dysphagia
• mild to moderate muscle wasting

diagnosis

• serum creatine kinase levels usually normal or only slightly elevated
• EMG may show non-specific myopathic features
• diagnosis on muscle biopsy
• inclusion bodies seen in rimmed vacuoles in skeletal muscle fibres

treatment

• steroids and immunosuppression generally ineffective
• rare patients reported who have made a response to treatment

pathogenesis

• unknown
• ubiquitin, prion protein, tau protein found in inclusions
• abnormal mitchondria seen in some case

© 2002, C.E. Kahn, Jr.
2002-04-18