Missed diagnoses of giant cell arteritis in acute ocular ischemia: A diagnostic blind spot

Abstract Background In patients >50 years of age, isolated acute visual symptoms may represent occult giant cell arteritis (GCA). Additionally, central retinal artery occlusion (CRAO) or ischemic optic neuropathy (ION) may present with isolated, acute ophthalmic symptoms. In such settings, GCA, a treatable vasculitis, is under-diagnosed or misdiagnosed, with catastrophic consequences. Objective To quantify diagnostic gaps in GCA evaluation among patients presenting with ocular ischemic symptoms in emergency settings, using both institutional and national datasets. Methods We conducted a retrospective cohort analysis using data from patients aged >50 years presenting to the emergency department (ED) with isolated ocular symptoms between 2021 and 2024. Datasets included the University of Kentucky (UKY) Epic EHR and Epic Cosmos (299 million patients nationwide). Patients were stratified into three cohorts: occult GCA, CRAO, and ION. Multivariable logistic regression was performed using standard statistical software to estimate predictors of GCA diagnosis, adjusting for temporal artery ultrasound (TAUS), temporal artery biopsy (TAB) and use of corticosteroid administration prior to a diagnosis. Results In the UKY dataset of 103 patients with acute ocular symptoms, 38.8% had confirmed GCA, 27.2% were clinically diagnosed, and 34% were ruled out. Among confirmed cases, 67.5% underwent TAUS and 17.5% had a TAB. A total of 66/103 (64%) received steroids before testing and 46/66 (69.7%) of them tested negative for GCA. In Epic Cosmos (nationwide) data, 62.8% of 17,372 patients lacked any testing; TAUS-specific data were unavailable. Among patients with CRAO (n=90) in the UKY cohort, 12.2% underwent TAUS, with 63.6% diagnosed with GCA; workup for stroke revealed an embolic stroke 22/90 (24.4%); 75.5% received no further workup after stroke evaluation was unrevealing and 1/90 underwent TAB that was negative, the patient received steroids prior. In Epic Cosmos, of 18,621 patients with CRAO, 561 underwent TAB (3%), and 5908 (31%) had ultrasound but TAUS-specific data was unavailable. Among 594 UKY patients with ischemic optic neuropathy (ION), 28 had carotid ultrasound or TAUS; 15 had TAUS, with 33% diagnosed as having GCA; 9 underwent TAB and 33% had GCA. Additionally, 94.1% of the UKY cohort had no testing for GCA; In Epic Cosmos, of the 56554 patients with ION, 2686 (4.7%) underwent carotid U/S or TAUS, or both. 901(1.6%) underwent TAB, while 52967/56554 (93.6%) had no formal testing for GCA. Conclusions GCA is underdiagnosed among patients presenting with acute ocular ischemic syndromes and TAUS, a point-of-care non-invasive diagnostic tool, is underutilized. Integrating TAUS into ED protocols for ocular ischemia could reduce diagnostic delays and prevent irreversible blindness.