Rapid progression of large intracranial cerebral artery involvement in a patient with myeloperoxidase antineutrophil cytoplasmic antibody-associated vasculitis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic necrotizing vasculitis that predominantly affects small vessels of the body. The two most common ANCAs are myeloperoxidase ANCA and proteinase 3 ANCA. Neurological manifestations are frequent in patients with AAV, including peripheral neuropathy, meningitis, and stroke. AAV-associated ischemic stroke usually affects small vessels supplying the white matter or brainstem. This case report details the presentation and treatment course of a 70-year-old man with rapidly progressive multiple intracranial large artery involvement attributed to myeloperoxidase ANCA-associated vasculitis. Despite treatment with high-dose steroids and a rituximab infusion, the patient developed new speech difficulties and respiratory distress, and brain imaging confirmed new stroke lesions with progressive multiple intracranial large cerebral artery involvement. The patient died from SARS-CoV-2 infection 4 months after the diagnosis. This case emphasized the rare presentation of rapidly progressive large vessel involvement in a patient with myeloperoxidase ANCA-associated vasculitis despite active immunotherapy.