IgG4 Related Disease, A Case of Large Vessel Vasculitis.

Aim This report describes a case of large vessel vasculitis highlighting diagnostic and therapeutic challenges. It describes the use of the B cell depleting agent Rituximab in this setting. This is the case of a 50 year old lady with bipolar disorder presenting with lower limb pain. Method PET CT and CT angiography were employed in the diagnosis of a large vessel vasculitic process. Serum IgG4 was elevated. Histological sampling was not clinically feasible. A presumptive diagnosis of IgG4 related disease was made. Results The patient responded well to steroids and later rituximab. A prompt taper of steroids was required due to labile mood and Rituximab proved to be effective in this case as a maintenance therapy. Conclusion This case demonstrates that a combination of clinical findings, laboratory results and radiological imaging may be necessary for diagnosis for IgG4 related disease, especially in the absence of a histological diagnosis. Rituximab was used in this case as a maintenance therapy allowing for a relatively rapidly reducing course of steroids.