- Clinical science
Giant cell arteritis (GCA) is a type of autoimmune vasculitis that causes chronic inflammation of large and medium-sized arteries, in particular the carotid arteries, its major branches, and the aorta. It is most common in white women over the age of 50, and approximately 50% of patients also have polymyalgia rheumatica. Patients usually present with constitutional symptoms (e.g., fever, weight loss, night sweats, fatigue, and malaise), new-onset headache, a tender, hardened temporal artery, jaw claudication, or amaurosis fugax. Laboratory tests typically show signs of inflammation (e.g., elevated erythrocyte sedimentation rate and CRP), and temporal artery biopsy should be performed to confirm the diagnosis. The classic histopathological findings are mononuclear infiltration of the vessel wall and formation of giant cells. If GCA is suspected, prompt administration of glucocorticoids is essential to reduce the risk of permanent vision loss and cerebral ischemia.
- Local vascular damage: macrophages produce metalloproteinases → destruction of vessel wall structures (e.g., )
- Concentric intimal hyperplasia: macrophages and giant cells produce PDGF and VEGF → stimulate intimal proliferation → reduced blood flow and ischemia
- Constitutional symptoms
- Symptoms of arterial inflammation: extracranial branches of the common carotid, internal carotid, and external carotid arteries (the temporal artery is the most commonly affected vessel)
- Scintillating scotoma
- Amaurosis fugax or permanent loss of vision
- Symptoms of (if both diseases are present)
- ACR criteria (3 of the 5 criteria are required)
- Laboratory tests
- Temporal artery biopsy (gold standard): mandatory in all patients
- Polymyalgia rheumatica
- Other vasculitides
- Other causes of monocular vision loss, e.g.:
The differential diagnoses listed here are not exhaustive.
- Ischemic organ damage (e.g., impaired vision): high dose of IV glucocorticoids or oral glucocorticoids
- Uncomplicated disease: medium dose of oral glucocorticoids
- After symptoms have resolved (usually after 2–4 weeks), slowly taper glucocorticoids to the lowest dose that is needed to control symptoms (The mean duration of treatment is 1–2 years).
- Low-dose aspirin to prevent ischemic complications
- Tocilizumab (antagonizes IL-6 receptor) may be used to reduce the required dose of steroids.
- Permanent vision loss: ∼ 20–30% if giant cell arteritis is left untreated
- Cerebral ischemia (e.g., transient ischemic attack and stroke): < 2% of cases
- Aortic aneurysm and/or dissection: ∼ 10–20% of patients
We list the most important complications. The selection is not exhaustive.