Case Presentation: A 63-year-old woman with hypertension and essential thrombocytosis presented with transient left eye vision loss. Imaging revealed a left parietal stroke, moderate stenosis of the left internal carotid artery (ICA), and diffuse intracranial atherosclerosis. She was discharged on dual antiplatelet therapy. One week later, she presented with complete left eye vision loss and new right-sided hemiparesis. Physical exam was notable for aphasia with right-sided hemiplegia, hemianopia and facial droop. Laboratory results were notable for platelets of 800,000/μL (normal: 150,000-450,000/μL), ESR 3 mm/hr (0–20 mm/hr) and CRP 0.7 mg/dL (< 1.0 mg/dL). Brain MRI showed hemorrhagic conversion of the prior infarct and new infarctions in the left middle cerebral artery (MCA), and deep watershed zones. MRA revealed further worsening of left ICA stenosis. Temporal artery biopsy confirmed giant cell arteritis (GCA). Additional workup revealed a JAK2 mutation. The remainder of the hypercoagulable workup was negative. Echocardiogram was unremarkable. The patient was treated with IV methylprednisolone, followed by an oral prednisone taper and aspirin monotherapy.The patient subsequently had multiple presentations for new strokes requiring pulse dose steroids. Despite initial steroid treatment, she experienced progressive right-sided weakness and vision loss. Imaging showed evolving infarcts in the left anterior cerebral artery and MCA. Due to steroid-refractory GCA, tocilizumab was initiated with steroid tapering, which subsequently halted further stroke recurrence.
Discussion: GCA is the most common primary systemic vasculitis in patients over 50 years of age, affecting large and medium-sized arteries, especially branches of the external carotid artery. Clinical presentation varies but often includes vision changes, headache, jaw claudication and constitutional symptoms. Stroke occurs in 3-7% of patients with GCA and typically involves the posterior circulation. However, in this case, infarcts were primarily in the anterior and middle cerebral arteries, highlighting the need to consider GCA even in less typical stroke patterns.Diagnosing GCA-related stroke is challenging, particularly in patients with vascular risk factors. The etiology of stroke in our patient was further confounded by the presence of essential thrombocytosis with a JAK2 mutation, a known prothrombotic state that likely contributed to the burden of recurrent strokes. While GCA causes vascular inflammation and luminal narrowing, JAK2-driven thrombocytosis can promote thrombus formation, further increasing stroke risk. Despite high-dose corticosteroids, the patient experienced progressive neurologic events, indicative of steroid-refractory GCA. The addition of tocilizumab, an IL-6 receptor antagonist, has shown benefit in reducing disease activity and steroid dependence and was initiated with subsequent tapering of corticosteroids, without recurrence of cerebrovascular events.
Conclusions: Hospitalists should maintain a high index of suspicion for vasculitis in older patients with multifocal or recurrent strokes, even when inflammatory markers are normal or vascular risk factors are present. Failure to respond to corticosteroids should prompt early rheumatology involvement and consideration of biologic therapy. Timely recognition and treatment escalation are critical to prevent permanent neurologic and visual morbidity.