Sudden altitudinal visual loss in an older man: is this GCA?
A 74-year-old hypertensive man presents with a 2-day history of painless loss of vision in the right eye, described as a curtain over the upper half of vision. Right eye: visual acuity 6/18, IOP 16 mmHg, a right relative afferent pupillary defect, and a swollen hyperaemic optic disc with a small cup; visual field shows an inferior altitudinal defect. Left eye: visual acuity 6/9, crowded disc, no swelling. He has no headache, jaw claudication, scalp tenderness or weight loss. ESR 32 mm/h, CRP 9 mg/L, platelets 280 x 10^9/L. He takes amlodipine and aspirin. He is due to fly abroad in 3 days.
1. How do you distinguish arteritic from non-arteritic anterior ischaemic optic neuropathy here, and what is the role of temporal artery biopsy?
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Distinguishing the two:
- Age over 70, hypertension and diabetes favour NAION, but giant cell arteritis can present identically; the absence of headache, jaw claudication or scalp tenderness does not exclude it.
- Disc appearance: chalky-white swelling with a small cup suggests arteritic disease; hyperaemic swelling in a crowded disc suggests NAION.
- ESR 32 and CRP 9 are within or near normal for a 74-year-old man, but a normal ESR does not exclude GCA (about 5-10% of biopsy-proven cases have a normal ESR); CRP is more sensitive.
- Temporal artery biopsy is the gold standard, but skip lesions mean a negative biopsy does not fully exclude GCA. It should be performed within 2 weeks of starting steroids.
My judgement: low but not zero suspicion. I would ask specifically about amaurosis, polymyalgia, fever and weight loss, and examine the temporal arteries.
2. Would you start high-dose corticosteroids now, and how do you counsel him about his travel?
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Steroid decision:
- If suspicion is low and he is systemically well with normal inflammatory markers, I would not start high-dose steroids immediately; I would arrange urgent temporal artery biopsy and review within 48 hours, with clear instructions to return if symptoms develop.
- If there were any red flags (jaw claudication, scalp tenderness, bilateral involvement, or a raised CRP), I would start oral prednisolone 60 mg, or intravenous methylprednisolone 500-1000 mg if the fellow eye were threatened, immediately before biopsy, because GCA can cause irreversible blindness.
- Steroids do not invalidate a biopsy if given within 2 weeks.
Travel:
- He should not fly until the diagnosis is clarified or a clear plan and follow-up are in place.
- If steroids are started, he needs monitoring for diabetes and hypertension, and a written plan for the trip.
3. What is the risk to the fellow eye, and how do you manage it?
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Fellow-eye risk:
- NAION: about 15-20% risk of sequential involvement over 5 years; there is no proven prophylaxis. Aspirin is often used but unproven; treat hypertension, diabetes and sleep apnoea, and avoid agents that lower nocturnal blood pressure.
- GCA: the fellow eye is at high risk (up to 50% within days), and high-dose steroids are protective.
Management either way:
- Document baseline visual acuity and visual fields in the left eye.
- Counsel about the small risk of second-eye involvement and the need to return urgently with any new visual symptoms.
- Review his antihypertensive timing to avoid nocturnal hypotension.