A Case of Giant Cell Arteritis With a Normal Erythrocyte Sedimentation Rate (ESR) Post ChAdOx1 nCoV-19 Vaccination.

Giant cell arteritis (GCA) has been reported post the coronavirus disease 2019 (COVID-19) vaccination, especially with the mRNA vaccine. A normal erythrocyte sedimentation rate (ESR) is seen in some GCA patients. This report describes a 68-year-old gentleman who presented with a right-sided temporal headache for three weeks, starting three to five days after his second dose of the ChAdOx1 nCoV-19 vaccine, a viral vector vaccine, which was given seven weeks post the first dose. On presentation, he developed blurred vision in the left eye, and it progressed to complete vision loss four days later. He also had episodes of blurred vision in the right eye. The blood test showed a mildly elevated C-reactive protein of 29 mg/L and a normal erythrocyte sedimentation rate (ESR) of 4 mm/hr. Optical coherence tomography showed anterior ischaemic optic neuropathy in the left eye and retinal ischemia in the right eye. Bilateral giant cell arteritis (GCA) was confirmed on temporal artery biopsy. He was treated with methylprednisolone pulse therapy followed by prednisolone. He re-presented with intermittent blurry vision in the right eye three months later. He was treated with methylprednisolone pulse therapy again, followed by prednisolone, aspirin, and tocilizumab. This case describes a patient who developed GCA post ChAdOx1 nCoV-19 vaccination with a normal ESR. Further studies are needed to investigate this relationship as causal or incidental and the likelihood of low-level inflammatory makers in such a situation.