âť“Whatâť“
- Large/medium-vessel vasculitis: while GCA is also known as “cranial/temporal arteritis,” this is misleading as many patients have large vessel-predominant disease (e.g. aortitis)
âť“Epidemiologyâť“
- Age: older adults (virtually never seen if younger than 50)
- Peak incidence: 70-80
- FUO: one study found 1 in 6 FUOs in older adults was due to GCA
âť“Presentationâť“
Path to the Problem đź—» = Age Over 50 + ___
- Unexplained fever/inflammatory symptoms, ↑ ESR/CRP
- Abrupt-onset ophthalmic symptoms (e.g. vision loss, diplopia)
- New vs. different headache/scalp pain syndrome
đź“š Polymyalgia Rheumatica (PMR) should prompt an intense search for any of the below symptoms due to its strong association with GCA
Non-Specific
- ~10% have inflammatory signs/symptoms without symptom localization, which puts GCA on the FUO DDx; however, of note, many of these patients have ⊕ large-vessel imaging (e.g. aortitis)
MEDIUM Vessel = ”Cranial/Temporal Arteritis”
- Ophthalmic: painless vision loss (~85% due to posterior ciliary artery occlusion), diplopia (due to ischemia to any portion of oculomotor system)
- Pain: headache & scalp pain/tenderness (~2/3), jaw/tongue claudication (~1/2)
đź“š Any of these symptoms can be sudden-onset, transient, & recurrent if vasospasm is the ischemic mechanism (compared to persistent vessel occlusion)
LARGE Vessel = Less Common
- Aortitis: inflammatory chest pain → aneurysms, dissections, stenosis
- Subclavian → Axillary arteritis: limb claudication → BP discrepancy, ↓ radial pulse
- Vertebrobasilar arteritis: very rarely, posterior circulation ischemic stroke (>50% in vertebrobasilar system; bilateral vertebral arteritis is extremely suggestive)
📚 GCA patients with large-vessel disease are less likely to have cranial/temporal symptoms (~40% vs. ~80%), & there is a corresponding decrease in temporal artery biopsy positivity (only ~50% positive)
Other
- Very rarely, may be accompanied by RS3PE
âť“Diagnosisâť“
- Rule Out: negative ESR/CRP in only ~5%, so if low pre-test probability, can be used to rule-out.
- Biopsy: While Doppler ultrasound is still being studied, temporal artery biopsy remains the gold-standard test, & scheduling this should not delay empiric glucocorticoid treatment due to risk of vision loss.
- What if the biopsy is ⊖ but the pre-test probability was high? Large-vessel imaging can be pursued (CTA, MRA, PET) if large-vessel disease is suspected. (These tests are not helpful for medium-vessel/cranial disease due to lower sensitivity.)
- What if the biopsy & imaging are ⊖ but the pre-test probability was high? Dr. John Stone recommends making a clinical diagnosis even before biopsy & imaging comes back due to the sensitivity of biopsy being no more than ~50%.
âť“Treatmentâť“
- ⥀ vision loss: 40 to 60 mg/day prednisone
- (+) vision loss: 500 to 1000 mg/day IV methylprednisolone x 3 days → 40 to 60 mg/day prednisone
- Adjunctive: the ACR currently recommends toci- for all patients given glucocorticoids alone are not sufficient for many patients
📚 References 📚
