Distinguishing Retinal Arteritis from Retinal Phlebitis

Key Clinical Distinctions

• Boxcar segmentation (slow, segmented blood flow) in retinal arterioles is a diagnostic feature of retinal arteritis, particularly in cases of embolic disease from carotid stenosis or cardiac sources 1

Critical Etiologic Considerations

• Giant Cell Arteritis (GCA) is the most common non-embolic cause of retinal arteritis in patients over 50 years, requiring immediate high-dose corticosteroids, as recommended by the American Academy of Ophthalmology 2, 3
• Embolic disease from carotid stenosis or cardiac sources presents with arterial occlusion patterns, and the American Heart Association recommends immediate evaluation and treatment to prevent further complications 1, 2

Practical Diagnostic Algorithm

• The American Academy of Ophthalmology recommends performing dilated fundoscopy looking specifically for arterial versus venous sheathing patterns, and obtaining fluorescein angiography to document arterial filling times, vascular leakage patterns, and areas of nonperfusion 2
• The use of OCT to identify paracentral acute middle maculopathy (PAMM) suggesting arterial ischemia is also recommended by the American Academy of Ophthalmology 2

Critical Pitfalls to Avoid

• The American College of Cardiology and the American Heart Association recommend never delaying GCA workup in patients over 50 with arteritis, and checking ESR, CRP immediately and starting corticosteroids if clinical suspicion is high 2, 4
• Arteritis requires immediate stroke center referral within 24 hours as it represents a stroke equivalent with 3-6% stroke risk in the first 1-4 weeks, as recommended by the American Stroke Association 5, 3