Beyond the Temporal Artery: Atypical Mesenteric Vessel Involvement in Giant Cell Arteritis

Objective To highlight the importance of additional vascular imaging for patients with Giant Cell Arteritis (GCA). Background GCA, the most common systemic vasculitis, presents with headache, scalp tenderness, visual disturbances, and systemic symptoms. Large artery involvement is less common and typically involves the aorta and its proximal branches, most often in the upper extremities. Mesenteric vessel involvement is rare. Design/Methods NA. Results We present a 70-year-female with hypertension, hyperlipidemia, and diabetes who presented to the hospital for right eye vision loss. MRI brain was negative for stroke. ESR was elevated at 77. Due to high suspicion for temporal arteritis, she was started on high-dose steroids and underwent a temporal artery biopsy. On follow up, her vision had improved. Her biopsy resulted with rare mononuclear cells with histiocytes and severe disruption of the elastic lamina suggestive of remote or treated arteritis. Due to refractory hyperglycemia and recurrent hospitalizations for diabetic ketoacidosis, she was unable to tolerate a prednisone taper and ultimately transitioned to Tocilizumab with improved glycemic control. Later, she developed sharp right-sided abdominal pain, diaphoresis, and general malaise concerning for large-vessel vasculitis. MRA chest, abdomen, and pelvis showed multifocal areas of arterial wall thickening and postcontrast enhancement in the right brachiocephalic artery with extension to the origin the right subclavian artery as well as in the mesenteric arteries (SMA and IMA), and left common iliac artery. Conclusions This case highlights the importance of additional imaging to assess for underrecognized large-vessel involvement in patients with newly diagnosed GCA. Extracranial imaging detects aortitis in up to 83% of cases. Given this patient’s imaging findings and rarity of mesenteric vessels involvement in GCA, chronic mesenteric ischemia should be considered. Active extracranial large-vessel GCA would require prolonged, intensive therapy with glucocorticoids plus a steroid-sparing agent and carries a higher risk of relapse, making distinction in diagnosis essential.