Giant Cell Arteritis With Atypical Features: Acute Vision Loss and Marked Eosinophilia Mimicking Systemic Vasculitis

Giant cell arteritis (GCA), also known as temporal arteritis, is a chronic inflammatory vasculitis that affects the large- and medium-sized arteries, which commonly includes the cranial branches of the carotid arteries. Manifestations range from constitutional symptoms, headache, and jaw claudication to transient or permanent monocular vision loss. Because its prognosis is poor if untreated, patients require prompt evaluation and appropriate treatment. We present an atypical case of binocular vision loss in a patient diagnosed with GCA with eosinophilic granulomatosis with polyangiitis. The patient declined a temporal artery biopsy and opted for ultrasonography, which helped clinch the ultimate diagnosis. His symptoms partially improved with high-dose steroids and tocilizumab in the hospital. Our case highlights the diagnostic challenges, appropriate specialist consultations required, and prompt management of GCA with overlapping vasculitis symptoms.