Giant cell arteritis: ophthalmic manifestations of a systemic disease

Background: Giant cell arteritis (GCA) is a systemic granulomatous vasculitis, primarily affecting medium-large arteries. It has a predilection for the aorta and its major branches, including the carotid and vertebral arteries. Ophthalmic artery involvement frequently leads to irreversible visual loss, and therefore GCA is one of the few true ophthalmic emergencies. GCA, although classified as a large vessel vasculitis, is known to affect smaller-sized vessels, resulting in a multiplicity of signs in the eye, some of which are often missed. Purpose: We set out to highlight some of the less frequently observed clinical signs, which may provide clues to clinically diagnosing GCA in patients presenting with non-classical features and inconclusive inflammatory markers. Methods: We review the literature and describe the diverse ocular features and some of the systemic findings that can be associated with GCA. Results: Although the most common ocular manifestation of GCA is anterior ischaemic optic neuropathy, the clinical presentation of GCA can vary dramatically. In the absence of obvious ocular involvement, more subtle ophthalmic signs of anterior segment ischaemia, such as hypotony and anisocoria, may be present at the time of initial clinical examination. Conclusion: There are no specific biomarkers for disease to date; therefore, pertinent history and clinical examination can guide towards diagnosis in the acute setting. The diagnostic process is not always straightforward, yet appropriate and prompt diagnosis is critical to enable timely intervention and prevent significant morbidity.