Incidence of giant cell arteritis mimicking non‐arteritic anterior optic neuropathy

Authors: Mariam Issa¹, Laura Donaldson², Edward Margolin³. ¹Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada, ²Department of Ophthalmology, McMaster University, Hamilton, Ontario, Canada, ³Department of Ophthalmology and Medicine (Neurology), University of Toronto.

Author Disclosures: Mariam Issa: None Laura Donaldson: None Edward Margolin: None 


Abstract Body: 

Purpose: Giant cell arteritis (GCA) involving ophthalmic circulation often manifests as anterior ischemic optic neuropathy (AAION), presenting with severe vision loss and pallid optic disc edema. Non‐arteritic anterior ischemic optic neuropathy (NAION) classically presents with segmental optic disc edema and corresponding altitudinal visual field defect (VFD) with small cupto‐disc ratio in the fellow eye. Differentiating these two entities is critical as GCA requires immediate treatment to prevent vision loss in the fellow eye. This study investigated how often GCA mimics NAION at presentation. 

Study Design: Retrospective case series. 

Methods: Retrospective chartreview of patients with temporal artery biopsy (TAB) positive GCA with ocular manifestations seenat a tertiary neuro‐ophthalmology practice between 2015 and 2020. Patients presenting with segmental non‐pallid optic disc swelling and corresponding altitudinal VFD mimicking NAION were identified. 

Results: The clinical presentation of 7.1% (3/42) of patients with TAB‐positive GCA mimicked NAION. Two of three patients had cup‐to‐disc ratio of <0.3 in the fellow eye. Two patients were women, mean age was 67.3 ± 6.5 years, and mean presenting visual acuity was 0.45 ± 0.48 LogMAR. Two patients had a normal temporal artery ultrasound. Two of three patients had at least one systemic symptom of GCA at presentation and all had elevation of one or both inflammatory 
markers. 

Conclusions: There should be high index of suspicion for GCA in patients with suspected NAION. Inflammatory markers must be checked in every patient with presumed NAION and TAB performed if one or both are elevated to avoid missing GCA.

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