A case of large-vessel giant cell arteritis onset in a patient over 90 years old: Diagnostic challenge in differentiating from an infectious aneurysm.

UNLABELLED: Giant cell arteritis (GCA) is a large-vessel vasculitis that can involve extracranial arteries, such as the aorta, leading to aneurysm formation. However, differentiating aneurysms caused by large-vessel GCA (LV-GCA) from infectious aortic aneurysms remains a diagnostic challenge. We report a rare case of a 91-year-old man with anorexia, weight loss, and low-grade fever. Laboratory findings revealed elevated inflammatory markers, and contrast-enhanced computed tomography (CT) showed saccular aneurysms of the descending and abdominal aorta with periaortic soft tissue mass. Although empirical antibiotic therapy was initiated for suspected infectious aortic aneurysm, there was no clinical or laboratory improvement, and blood cultures remained negative. Positron emission tomography-CT demonstrated intense fluorodeoxyglucose uptake at aneurysmal sites. After multidisciplinary discussion, a diagnosis of LV-GCA was made, and prednisolone 40 mg/day was initiated, resulting in rapid symptom resolution and normalization of inflammatory markers. Despite initial improvement, relapse occurred during glucocorticoid tapering, and the patient unfortunately suffered aneurysmal rupture and died. This case underscores the difficulty in differentiating LV-GCA from infectious aneurysms and highlights the importance of considering early initiation of biologic therapy, such as interleukin-6 receptor inhibitors, in LV-GCA to prevent relapse and potentially life-threatening complications.

LEARNING

OBJECTIVE

This case highlights the diagnostic challenges in distinguishing large-vessel giant cell arteritis (LV-GCA) from infectious aortic aneurysms, as both can present with similar imaging and clinical features. It also underscores the importance of considering early initiation of biologic therapy, such as interleukin-6 receptor inhibitors, in LV-GCA to prevent relapse and potentially life-threatening complications.