Posterior circulation stroke as the initial manifestation of giant cell arteritis: a case report

Background Giant cell arteritis (GCA) is a granulomatous vasculitis affecting medium and large arteries and is associated with severe complications including irreversible visual loss and aortic disease. Ischaemic stroke is an uncommon manifestation of GCA, but when present demonstrates a marked predilection for the vertebrobasilar circulation. Diagnosis may be challenging in the absence of classical cranial symptoms. Case Presentation A man in his 80s presented following an unwitnessed collapse and was found to have acute bilateral visual loss. CT brain and CT angiography demonstrated multifocal posterior circulation infarcts involving the bilateral occipital lobes and cerebellum with occlusion of the left posterior cerebral artery. MRI confirmed multifocal subacute infarction with haemorrhagic transformation. Initial investigations also identified a suspicious spiculated right upper lobe pulmonary lesion. FDG-PET performed for pulmonary malignancy evaluation demonstrated diffuse arterial uptake involving the brachiocephalic, carotid, subclavian, vertebral, and internal mammary arteries, raising suspicion for large-vessel vasculitis. Temporal artery biopsy subsequently confirmed GCA. The patient was commenced on high-dose corticosteroid therapy; however, bilateral functional blindness persisted, requiring discharge to residential aged care. Conclusion This case highlights an atypical presentation of GCA as multifocal posterior circulation stroke without preceding cranial or constitutional symptoms. Recognition of otherwise unexplained ischaemic stroke in conjunction with elevated inflammatory markers and large-vessel imaging abnormalities may facilitate earlier diagnosis and prompt initiation of immunosuppressive therapy in GCA-associated stroke.