Characterization of extracranial giant cell arteritis with intracranial involvement and its rapidly progressive subtype

Objective To characterize patients with extracranial giant cell arteritis with intracranial involvement. Methods In a multicenter retrospective study we included 31 patients with systemic GCA with intracranial involvement. Clinical characteristics, pattern of arterial involvement and cytokine profiles were assessed. Patients with GCA without intracranial involvement (n = 17), and with intracranial atherosclerosis (n = 25) served as controls. Results Erythrocyte sedimentation rate (ESR) was elevated in 18 (69.2%) patients with and in 16 (100%) without intracranial involvement (P = 0.02). Headache was complained by 15 (50.0%) patients with and 13 (76.5%) patients without intracranial involvement (P = 0.03). Posterior circulation arteries were affected in 26 (83.9%), anterior circulation arteries in 17 (54.8%) and both territories in 12 (38.7%) patients. Patients with GCA had vertebral artery stenosis proximal and, in contrast, patients with atherosclerosis distal to the origin of posterior inferior cerebellar artery (PICA). Among patients with GCA with intracranial involvement, 11 (37.9%) patients had a rapid progressive disease course characterized by short-term recurrent ischemic events. The median mRS at follow-up in these patients was 4 (IQR 2.0-6.0) and 4 (36.4%) patients died. Vessel wall expression of IL6 and IL17 was significantly increased in patients with rapid progressive course. Interpretation Typical characteristics of GCA, headache and an elevated ESR, are frequently absent in patients with intracranial involvement. However, differentiation of intracranial GCA from atherosclerosis can be facilitated by the typical pattern of vertebral artery stenosis. About one-third of patients with intracranial GCA had a rapid progressive course with poor outcome. IL17 and IL6 may represent potential future treatment targets. This article is protected by copyright. All rights reserved.