26th August 2024

A 54-year-old woman is referred to the clinic by her GP due to proximal muscle weakness

A 54-year-old woman is referred to the clinic by her GP due to proximal muscle weakness which has been getting progressively worse over the last 2 weeks. On examination, you note symmetrical 4/5 weakness in her hips and shoulders. The rest of the neurological exam is normal. You also note purple patches over her knuckles on both hands and her hands appear to be well used for her work as a human resources manager. She also appears abnormally sunburnt for this time of year around her neck and chest. On further questioning, the changes on her hands have only been present for the last couple of months.

What investigation is necessary to establish the diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.