Day #329 - Fever of Unknown Origin

Today we discussed a patient with fever of unknown origin (previous blogs here including links to the articles I mentioned)

I erred when I said that abdominal imaging was required prior to making the diagnosis -- however, given the ease at which we can get said imaging I would say that it probably *should* be required before labeling as FUO. Certainly, it should be the first test performed in the "second tier"

On the basis of profound inflammatory markers and microscopic hematuria (in the absence of other causes) I postulated that this case may be a medium-small vessel vasculitis such as microscopic polyangiitis. A classic NEJM review on small vessel vasculitis is available here and the corresponding article on medium vessel vasculitis is available here.

This article reviews the guidelines for the management of medium and small vessel vasculitis.