A 68-year-old woman comes to the emergency department due to an acute vision disturbance. She had an episode of dimming of vision in the left eye that occurred abruptly and resolved spontaneously in 20 minutes. For the past several weeks, the patient has had a dull ache in the left side of her jaw while chewing that resolves when she stops eating. She has also had malaise and hip muscle aches over the last several months. The patient has a history of hypertension and hypothyroidism. On examination, her blood pressure is 130/70 mm Hg and pulse is 66/min. Neurological examination, including cranial nerves and motor and sensory functions, is unremarkable. Visual acuity, visual fields, and appearance of the ocular fundi are normal. Which of the following is the best initial test for this patient?
Giant cell arteritis | |
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This patient, an elderly woman with jaw claudication and an episode of amaurosis fugax (ie, transient monocular visual loss), most likely has giant cell (temporal) arteritis (GCA). GCA a common form of vasculitis and occurs almost exclusively in patients age >50. About half of patients with GCA will also have polymyalgia rheumatica, which causes achy pain in the shoulder and hip girdles. Headache is the most common presentation of GCA, but jaw or tongue claudication is also common. Ocular manifestations may include amaurosis, diplopia, blurred vision, and ischemic optic neuropathy; untreated GCA may lead to permanent blindness.
Physical findings in GCA may be normal, but patients often have tenderness over the course of the temporal artery. If GCA is suspected, a C-reactive protein (CRP) level or erythrocyte sedimentation rate (ESR) should be determined promptly. Although CRP and ESR are nonspecific, they are highly sensitive and almost always significantly elevated in GCA. Patients with characteristic symptoms and elevated CRP or ESR should undergo temporal artery biopsy for definitive diagnosis.
(Choice A) Angiography in GCA may show focal areas of arterial narrowing, but it is not as sensitive as ESR and CRP for initial assessment.
(Choice B) GCA is associated with an increased risk of cardiovascular events, including transient ischemic attack (TIA), stroke, and myocardial infarction. Appropriate management of other cardiovascular risk factors (eg, hyperlipidemia) is recommended but should not delay initial evaluation.
(Choice D) Noncontrast head CT is recommended for initial evaluation of patients with TIA and stroke. However, this patient has no focal neurologic deficits, and her amaurosis and jaw claudication are more consistent with GCA.
(Choice E) In addition to elevated ESR and CRP levels, other nonspecific signs of inflammation, such as thrombocytosis, may be present in patients with GCA. However, specific serologic markers, such as rheumatoid factor, are not elevated.
(Choice F) Echocardiography is recommended for patients with a suspected cardioembolic event. Although cardioembolism may rarely present with amaurosis, this patient's other features are more characteristic of GCA.
Educational objective:
Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) have very high sensitivity for giant cell (temporal) arteritis. Patients with suspected giant cell arteritis who have an elevated ESR or CRP level should be referred for temporal artery biopsy to confirm the diagnosis.