Inflammatory Myopathies Dermatomyositis • Onset: Subacute • Pattern: Proximal • CK: Up to 50X ULN • Autoantibodies: Anti-MDA5, anti-Mi-2, anti-TIF-1, anti-NXP-2 • Associated Features: Cancer-associated, periorbital heliotrope, shawl sign Polymyositis • Onset: Subacute • Pattern: Proximal • CK: Up to 50X ULN • Autoantibodies: Anti-synthetase • Associated Features: Diagnosis of exclusion Necrotizing Autoimmune Myositis • Onset: Acute or subacute • Pattern: Proximal • CK: >50X ULN • Autoantibodies: Anti-SRP, anti-HMGCR • Associated Features: Weakness is severe, initially worsens after offending med is discontinued Inclusion Body Myositis • Onset: Insidious/slow • Pattern: Proximal and distal • CK: Up to 10x ULN • Autoantibodies: Anti-cN1A • Associated Features: Develops over years, often diagnosed when patients don't respond to steroids - BWH Medicine Chiefs @BrighamChiefs #Inflammatory #Myopathies #differential #diagnosis #comparison #rheumatology #table
