Giant Cell Arteritis With Impending Fellow-Eye Risk
A 74-year-old woman presents with sudden painless loss of vision in the right eye upon waking 1 day ago. She reports 2 weeks of right temporal headache, scalp tenderness when combing her hair, and jaw pain when chewing. Visual acuity is counting fingers right and 20/25 left. There is a right relative afferent pupillary defect. Funduscopy shows right disc edema with a few splinter hemorrhages at the disc margin; the left disc is normal. Visual field testing shows an altitudinal defect in the right eye. Erythrocyte sedimentation rate is 84 mm/h and C-reactive protein is 36 mg/L. She has type 2 diabetes and hypertension. She denies flashing lights or floaters. She asks if she can wait for an outpatient temporal artery biopsy before starting steroids.
1. What is the leading diagnosis, what features support it, and what is the danger to the fellow eye?
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The leading diagnosis is giant cell arteritis with arteritic anterior ischemic optic neuropathy. Supporting features are age over 50, sudden painless unilateral vision loss, a right relative afferent pupillary defect, altitudinal field loss, disc edema, elevated ESR and CRP, and systemic symptoms of jaw claudication, scalp tenderness, and temporal headache. The danger is involvement of the fellow eye, which can occur within days to weeks without treatment. The diagnosis must be treated as a medical emergency. Diabetic retinopathy and hypertensive changes can coexist, but they do not explain the systemic inflammatory symptoms and markedly elevated inflammatory markers.
2. Explain why treatment should not wait for biopsy and outline immediate steroid management, including route and dose considerations given her diabetes.
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Do not wait for biopsy. Start high-dose systemic corticosteroids immediately, before the biopsy, because steroid treatment reduces the risk of second-eye involvement and may preserve remaining vision in the affected eye. A common approach is intravenous methylprednisolone followed by oral prednisone, or high-dose oral prednisone depending on local protocol and severity. In a patient with diabetes, expect hyperglycemia and monitor glucose closely; do not withhold steroids because of diabetes. Also address gastric protection, bone protection, and blood pressure. The biopsy can be performed after steroids have started and remains interpretable for days to weeks. The judgment is that the cost of waiting, irreversible blindness in the fellow eye, is greater than the small effect of steroids on biopsy yield.
3. Describe the role and timing of temporal artery biopsy and what monitoring is needed.
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Arrange temporal artery biopsy promptly, ideally within 1 to 2 weeks, and ensure an adequate specimen length, often at least 2 to 3 cm, because skip lesions occur. A negative biopsy does not exclude the diagnosis if clinical features are compelling. Treatment is continued and the diagnosis is managed clinically. Monitoring includes inflammatory markers, visual acuity, fundus examination, and steroid complications: glucose, blood pressure, bone density, infection risk, and mood. The steroid dose is tapered slowly guided by symptoms and inflammatory markers, with rheumatology involvement. The key is that biopsy confirms but does not gate emergency treatment.