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Giant cell arteritis (GCA) is a disease of the elderly, most commonly occurring in the 7th decade and almost never among patients less than 50 years of age. It is a form of vasculitis that involves the aorta and its branches. Constitutional symptoms such as fatigue and weight loss are common. About one-half of patients can have fevers.
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The more defining symptoms of GCA are the result of organ and tissue ischemia, caused by inflammatory narrowing of the lumen of the extracranial vessels. The reduced blood flow to facial muscles, the scalp, eyes, tongue, inner ear, and brain can result in a wide variety of symptoms. Headache and scalp tenderness are common presentations; however, they are very nonspecific. Importantly, there are no “typical” GCA headaches, as they can be frontal, temporal, occipital, unilateral, or generalized. The most specific symptom of GCA is jaw claudication as a result of reduced blood flow to the masticatory muscles. The clinical presentation of jaw claudication is often not straightforward. Patients may report facial pressure with talking, difficulties chewing, and problems with mouth opening or speaking.
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Vision loss is the most dramatic presentation of GCA and a common reason for patients to present to the ED. It is typically the result of arteritic anterior ischemic optic neuropathy, an inflammatory occlusion of the posterior ciliary arteries. Impairment of vision in patients with GCA is typically monocular and can initially present as transient visual loss (amaurosis fugax), visual field defects, or swift permanent vision loss. Although fundoscopy in these patients is typically abnormal (optic disc edema), fundoscopic findings are never pathognomonic for GCA. On rare occasions, fundoscopy can be completely normal in patients with acute vision loss and a GCA. This can occur in cases where the ocular symptoms are caused by posterior ischemic optic neuropathy or cortical ischemia.
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Symptoms of polymyalgia rheumatica, such as proximal myalgias and polyarthralgias, can be associated with GCA in up to one-third of cases.
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The diagnosis of GCA in the emergency setting will mostly rely on history and physical exam. Acute phase response parameters such as ESR or CRP are typically elevated but can be normal in rare cases. Although temporal artery biopsy, vascular ultrasound, magnetic resonance angiography, and positron emission tomography are important testing modalities to confirm a diagnosis of GCA, these are typically not available in the ED when a therapeutic decision needs to be made.
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Management and Disposition
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Patients with suspected GCA require prompt initiation of therapy with high-dose systemic glucocorticoids. This is particularly true for patients with ocular symptoms and threatened visual loss. Importantly, treatment should never be withheld while awaiting more definite tests such as a temporal artery biopsy if there is a strong clinical suspicion for GCA.
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In patients without visual symptoms, treatment with 1 mg/kg of prednisone equivalent is typically sufficient. ...