Remember – a lot of this diagnosis can be made with labs and a good physical exam!
Steroid induced myopathy – normal CK and normal DTRs
Critical illness myopathy/neuropathy – elevated CK and decreased DTRs
GBS – normal CK and decreased DTRs
Inflammatory myopathy – elevated CK with normal DTRs
If you have a patient who had inflammatory myopathy and was receiving steroids for treatment and despite a normalization in CK did not have improvement in weakness – wean off the steroids because this likely now became a steroid induced myopathy!