Inflammatory Myositis

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Introduction

Inflammatory myositis describes polymyositis and dermatomyositis. The main feature is muscle inflammation.

a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.

symmetric proximal muscle weakness

elevated serum muscle weakness

typical rash with DM, as opposed to PM

Gottron's papules

heliotrope rash - violet coloration of the eyelid

Shawl sign - maculopapular rash in mainly sunexposed areas

mechanic's hands - hyperkeratosis and cracking

multiple organs involved: muscles, skin, lungs, heart, GI tract

myopathic changes on EMG

characteristic muscle biopsy changes

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