Giant cell arteritis imitating dural arteriovenous fistula: Diagnostic pitfalls and the importance of timely corticosteroid treatment – A case report

Visual disturbances and chronic headaches in the elderly often prompt investigation for intracranial vascular anomalies such as dural arteriovenous fistulas (DAVFs). However, giant cell arteritis (GCA) - a systemic vasculitis - can present with similar symptoms and even mimic DAVF radiologically. Misdiagnosis may delay appropriate treatment and result in irreversible complications such as vision loss. We report a case of a 65-year-old male presenting with progressive bilateral visual impairment and a longstanding headache. Initial magnetic resonance angiography (MRA) suggested DAVF involving the ophthalmic and internal maxillary arteries, with associated vascular dilatation. However, digital subtraction angiography (DSA) revealed bilateral dilatation and sluggish contrast flow in the superficial temporal arteries - findings more indicative of GCA. High-dose oral prednisone (40–60 mg/day) was initiated, followed by a gradual taper. Within one month, the patient experienced marked improvement in both visual acuity and headache symptoms. While DAVF and GCA are distinct vascular disorders, overlapping clinical features and imaging findings can lead to diagnostic confusion. DAVFs typically show arteriovenous shunting and venous congestion, while GCA demonstrates arterial wall inflammation and altered flow patterns. In this case, DSA played a pivotal role in clarifying the diagnosis. Early corticosteroid therapy, as recommended by major rheumatologic societies, was effective in reversing symptoms and preventing visual deterioration. This case highlights the importance of thorough vascular imaging interpretation and clinical judgment in differentiating DAVF from GCA. Prompt and accurate diagnosis, coupled with early corticosteroid treatment, can significantly reduce morbidity and preserve vision in elderly patients presenting with overlapping vascular symptoms.