A severe cerebral infarction associated with giant cell arteritis, which developed during tocilizumab therapy and was successfully treated with intravenous cyclophosphamide.

Giant cell arteritis (GCA) is a large vessel vasculitis that primarily involves aorta and its major branches. Cerebral infarction is a serious complication that can occur secondary to GCA in up to 3% of patients with a mortality rate of over 50%. Due to the rarity of this severe complication, no therapeutic strategies are currently available. Furthermore, despite the recent progress in molecular-targeted therapy for GCA, it remains unknown whether tocilizumab is effective for severe ischemic complications such as cerebral infarction. The accumulation of individual cases in which this fatal complication could be treated is apparently required to build a better management of the disease. We present our case of GCA that developed severe cerebral infarction during high-dose glucocorticoid and tocilizumab therapy, and its symptoms and image findings were improved by switching to intravenous cyclophosphamide. Our case suggests that an intensive immunosuppressive therapy, including cyclophosphamide, may be necessary to stabilise this fatal complication of GCA.