Giant Cell Arteritis (GCA) is a potentially vision-threatening condition that often presents with symptoms like new-onset headaches, visual disturbances, and elevated inflammatory markers like ESR and CRP. However, challenges with diagnosis arise when patients exhibit atypical symptoms. Early recognition is crucial to prevent irreversible vision loss. We report a rare and diagnostically challenging case of GCA with atypical clinical presentation, which initially suggested an alternative ocular etiology.

A 59-year-old male with a history of left internal carotid artery aneurysm post-stent, hyperlipidemia, and peripheral vascular disease presented with a 3-month history of intermittent, left-sided headaches, and neck pain. Over the course of three days, he developed worsening photophobia and blurred vision in the left eye. Lab work up showed normal ESR and CRP levels, and unremarkable MRI brain and cervical spine imaging. Initial ophthalmologic evaluation suggested floppy eyelid syndrome as the cause of his visual symptoms. Treatment for ocular issues did not alleviate his headaches, raising suspicion for GCA. Temporal artery duplex ultrasound revealed bilateral temporal artery inflammation with the classic hypoechoic halo sign, confirming the diagnosis. Prednisone 60 mg daily was initiated, leading to symptom improvement. The overlapping ocular condition and prolonged nature of the headache delayed the diagnosis.

This rare case highlights the importance of having high index of suspicion for Giant Cell Arteritis, when presented with normal inflammatory markers and atypical clinical presentation. Timely recognition and comprehensive evaluation are prudent to prevent irreversible vision loss.