Table 1.
(1) Symmetrical weakness of limb-girdle muscles and anterior neck flexor | |
(2) Muscle biopsy shows evidence of characteristic myositis | |
(3) Elevated serum skeletal muscle specific enzyme, especially creatinine phosphokinase | |
(4) Electromyographic (EMG) evidence of myositis | |
(5) Typical dermatomyositis rash, including heliotrope and Gottron's papules |
Definite polymyositis: all of items (1)–(4); probable: any three of items (1)–(4); possible: any two of items (1)–(4).
Definite dermatomyositis: item 5 plus any three of items (1)–(4); probable: item 5 plus any two of items (1)–(4); possible: item 5 plus any one of items (1)–(4).