Describe an atypical case of giant cell arteritis (GCA), lacking its classic systemic features and presenting as vertebrobasilar strokes, emphasizing the importance of considering GCA in older patients with elevated inflammatory markers—even in the absence of typical signs, symptoms, or imaging findings.

An 86-year-old woman with multiple sclerosis and a recent pontine infarct on dual antiplatelet therapy presented with acute binocular diplopia. Examination revealed severe dysarthria, right hemiparesis, right facial droop, and left cranial nerve III and cranial nerve VI palsies. MRI with contrast demonstrated multiple acute infarcts in the bilateral cerebellar hemispheres and left ventral midbrain with the subacute known left pontine insult. Orbital fat stranding and bilateral patchy enhancement were also noted. CTA showed bilateral vertebral artery irregularities throughout the course of the cervical vessels with multifocal occlusions on the left side, interpreted initially as vertebral artery dissections. There was no arch, subclavian, or proximal carotid involvement. Despite the absence of classic symptoms (headache, fatigue, jaw claudication, vision loss) and a normal fundoscopic exam, giant cell arteritis was suspected based on imaging and persistently elevated inflammatory markers. High-dose intravenous methylprednisolone was initiated. Temporal artery biopsy confirmed the diagnosis.

GCA should remain on the differential for older patients with posterior circulation strokes who present with unexplained elevated inflammatory markers and vasculopathy, even without classic clinical or imaging findings.