Ischemic ocular manifestations of giant cell arteritis: A Canadian case series

BACKGROUND: Diagnosing giant cell arteritis (GCA) can be challenging due to the variable clinical presentation and lack of systemic symptoms in approximately 20% of cases, which are termed occult GCA. GCA affects the ocular circulation in more than half of cases and can cause irreversible bilateral blindness if not rapidly recognized and treated. We compared clinical and laboratory findings of patients with occult and systemic temporal artery biopsy (TAB)-positive GCA with ocular manifestations. METHODS: Retrospective chart review of patients with TAB-positive GCA with ocular manifestations seen at a tertiary neuro-ophthalmology practice between 2015 and 2020. RESULTS: GCA was occult in 14.3% (6/42) and systemic in 85.7% (36/42) of patients. Occult GCA affected older patients (average age 84.6 ± 5.3 vs 75.9 ± 8.2). There was no significant difference in ESR or CRP levels between two cohorts. In patients with occult GCA, 83.3% (5/6) presented with AION, and 16.7% (1/6) with isolated cranial nerve six palsy (CN6P). In the systemic GCA cohort, 47.2% (17) presented with AION, 5.6% (2) with CRAO, 2.8% (1) with PION, 2.8% (1) with isolated CWS, 2.8% (1) had both CRAO and AION, 2.8% (1) isolated cranial nerve 4 palsy (CN4P), 2.8% (1) isolated CN6P, 22.2% (8) had history of amaurosis fugax but normal examination, and 11.1% (4) had visual symptoms but a normal exam. Three of the above patients with AION also had CN4P. Of patients diagnosed with AION, presenting visual acuity in the affected eye(s) was significantly worse in patients with occult GCA. Involvement of multiple ocular circulations was seen in six patients in the systemic group but none in the occult group. CONCLUSION: Occult GCA occurs more commonly in older patients who most of the time present with AION. Levels of inflammatory markers were similar in the occult and systemic groups. Though ocular ischemic manifestations were similar in both cohorts, in systemic GCA involvement of multiple ocular circulations is likely more common GCA should always be considered in older patients who present with signs of retinal and/or optic nerve head ischemia (AION and/or CWS) and new onset of CNPs, especially in patients where more than one ocular arterial circulation is involved.