Transient Monocular Vision Loss in a Patient on Aspirin
A 68-year-old retired teacher presents with three episodes over the past 10 days of a "gray curtain" descending over the left eye, each lasting 3–5 minutes and resolving completely. She has hypertension and hyperlipidemia and takes low-dose aspirin. She mentions that her jaw feels tired when chewing steak and that her scalp is tender when she brushes her hair. Visual acuity is 20/25 OD and 20/30 OS; pupils are equal and reactive without a relative afferent pupillary defect; IOP is 16 mmHg OU; fundoscopy shows healthy optic discs and no Hollenhorst plaque. She has a dental cleaning scheduled this afternoon and asks whether the visual episodes can be evaluated at a routine visit next month. Your office does not have same-day erythrocyte sedimentation rate or C-reactive protein testing, and the local laboratory closes in two hours.
1. What is the most likely diagnosis, and what makes same-day action necessary rather than waiting for next month?
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The leading diagnosis is giant cell arteritis (GCA) with amaurosis fugax. The combination of age over 50, recurrent transient monocular visual loss, jaw claudication, and scalp tenderness is a classic GCA red-flag cluster; a normal fundus and absence of a Hollenhorst plaque do not exclude it. Aspirin is not protective against GCA-related ischemia. Waiting a month risks irreversible anterior ischemic optic neuropathy or central retinal artery occlusion in the affected eye and, because GCA is bilateral, the fellow eye. The judgement point is that this is not a routine 'floater' or dry-eye visit: the history itself creates an emergency despite 20/30 acuity. I would treat this as same-day, not next-month, regardless of the schedule. If I could not arrange urgent evaluation, I would send her to the emergency department with a written note describing the red flags. I would also ask about polymyalgia rheumatica symptoms-proximal stiffness, fever, weight loss-because they raise pretest probability.
2. Outline your immediate actions and how you would coordinate care given the laboratory deadline.
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Draw ESR and CRP immediately and do not delay corticosteroid treatment while awaiting results if GCA is strongly suspected and there is no contraindication. In many settings the optometrist should phone the primary care physician or rheumatologist and arrange same-day temporal artery biopsy; if that is not possible, the emergency department is the safer pathway. I would explain that the biopsy can be falsely negative because of skip lesions and that steroids are usually started before biopsy, not after. I would document the time of arrival, the specific red-flag history, the visual acuity and fundus findings, the consultations attempted, and the patient's understanding. Because the laboratory closes in two hours, I would call ahead, use a stat order, and give the patient written directions rather than relying on a routine requisition. I would also advise her not to drive herself if she develops visual loss and to return immediately. The goal is to compress the interval between suspicion and steroid or biopsy decision, not to complete a leisurely workup.
3. If the ESR and CRP come back normal, how should that affect your management?
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A normal ESR and CRP do not exclude GCA, so I would not be reassured into inaction. A minority of biopsy-proven GCA cases have normal inflammatory markers, and markers can be normal early or blunted. The decision should remain driven by the clinical syndrome: age, amaurosis, jaw claudication, and scalp tenderness. I would proceed with the same urgent rheumatology or emergency referral and temporal artery biopsy, and I would not withhold steroids solely because the labs are normal. I would broaden the differential only after GCA is addressed-carotid embolic disease, migraine, seizure, and ocular surface disease are possibilities, but none explains jaw claudication and scalp tenderness together. I would record the normal results, my continued suspicion, and the advice given. If the patient is already on steroids, I would not stop them based on normal labs; the biopsy result and clinical response guide duration. This is a classic test of whether the clinician treats the patient or the number.