Supplementary Material for: Intracranial giant cell arteritis progressing despite treatment with high doses of corticosteroids: case report

A 64-year-old man presented with unilateral visual loss. He had systemic symptoms of giant cell arteritis (GCA), however, both inflammatory markers were normal. He was diagnosed with arteritic anterior ischemic optic neuropathy after temporal artery biopsy revealed classic findings of GCA and treated with high-dose corticosteroids. Despite appropriate treatment, serial imaging revealed progressive narrowing of intracranial arteries, predominantly involving anterior circulation of the brain. This case highlights that GCA can rarely present with normal inflammatory markers, involve intracranial vasculature, and progress despite treatment with high doses of corticosteroids emphasizing the importance of advanced imaging and potential need for adjunctive immunosuppressive therapy in patients with refractory disease.