Anna and Auntie Jo

🗒️ Question 

A 45 year old woman presents to clinic with a 6 month history of progressive muscle weakness and a rash. She reports difficulty climbing stairs and rising from a seated position. On examination, she has a violet-coloured rash over her eyelids and erythematous papules over her knuckles.

Laboratory tests reveal the following:

• Creatine kinase (CK): 1250 U/L (normal: 38-174 U/L)

• ESR: 50 mm/hr (normal <20)

• ANA: Positive

• Anti-Jo-1 antibody: Positive

What is the most likely diagnosis?

(A) Systemic lupus erythematosus
(B) Polymyalgia rheumatica
(C) Dermatomyositis
(D) Rheumatoid arthritis
(E) Systemic sclerosis