STEPTRACKERCARDIOVASCULAR | PATHOLOGY + IMMUNOLOGY | HIGH-YIELD REVIEW

Large-Vessel Vasculitis

Granulomatous inflammation of the aorta and its major branches — giant cell arteritis in older adults, Takayasu in young women.

FOCUS ON
Both are granulomatous and both raise the ESR; age separates them (> 50 vs < 40). Giant cell arteritis threatens vision, so give steroids before the biopsy result. Takayasu is the "pulseless disease" of the aortic arch. Polymyalgia rheumatica travels with GCA.
FEATURE
GIANT CELL (TEMPORAL) ARTERITIS
TAKAYASU ARTERITIS
EXAM CLUE
Who
> 50 years, women; Northern European ancestry
< 40 years, women; Asian ancestry
Age is the first discriminator
Vessels
Carotid branches — temporal, ophthalmic, vertebral; also aorta
Aortic arch and its branches (subclavian, carotid); pulmonary artery
GCA = head · Takayasu = arch
Pathology
Granulomatous inflammation with giant cells; fragmented internal elastic lamina; intimal thickening; segmental (skip lesions)
Granulomatous thickening of the aortic arch; narrowed branch origins
Both are Th1/IL-6 driven
Symptoms
New unilateral headache, scalp/temporal artery tenderness, jaw claudication, visual loss; fever, weight loss
Weak or absent arm pulses, arm claudication, BP difference between arms, bruits, dizziness; fever, night sweats
"Pulseless disease"
Labs
Very ↑ ESR and CRP
↑ ESR
Normal ESR makes GCA unlikely
Complications
Irreversible blindness (ophthalmic artery), stroke; later thoracic aortic aneurysm
Aortic regurgitation, renal artery stenosis → hypertension, stroke
—
Diagnosis
Temporal artery biopsy (may miss skip lesions); ultrasound "halo"
CT or MR angiography
Negative biopsy doesn't rule out GCA
Treatment
High-dose steroids immediately; tocilizumab (IL-6R) to spare steroids
Steroids; immunosuppressants; revascularization if needed
Don't delay steroids for the biopsy
Polymyalgia rheumatica
GCA companion
Pain and morning stiffness of shoulder and hip girdles in > 50s; ~half of GCA patients have it
—
↑ ESR, normal CK; dramatic response to low-dose steroids

Mechanism — granulomas in the wall

Dendritic cells in adventitiaActivated
→
Th1 + Th17IFN-γ, IL-6
→
Macrophages + giant cellsElastic lamina destroyed
→
Intima thickensLumen narrows
→
IschemiaBlindness, claudication

Vasculitis map by vessel size

SIZE
DISEASES
Large — aorta and major branches
Giant cell arteritis, Takayasu
Medium — main visceral arteries
Polyarteritis nodosa, Kawasaki, Buerger (page 7.02)
Small, ANCA — arterioles, capillaries
GPA, MPA, EGPA (page 7.03)
Small, immune complex
IgA vasculitis, cryoglobulinemic, cutaneous leukocytoclastic (page 7.04)
Variable size
Behçet, Cogan

How it's tested

COMMON CONFUSIONJaw pain on chewing is not TMJ disease in a 70-year-old with headache and a high ESR. It is jaw claudication from GCA.
THE TRAP"What is the next step?" in suspected GCA is high-dose steroids now, then the biopsy. Waiting risks permanent blindness.
YOUR APPROACHGranulomatous large-vessel vasculitis → age → GCA (head, vision) or Takayasu (arch, pulses) → steroids.

If you see… think…

72-year-old woman, new headache, jaw claudication, ESR 95 → GCA — steroids now
Sudden monocular vision loss in GCA → ophthalmic artery ischemia
Shoulder and hip stiffness, ↑ ESR, normal CK → polymyalgia rheumatica
Young Asian woman, absent radial pulse, arm claudication → Takayasu arteritis
30 mmHg BP difference between arms in a young woman → Takayasu (subclavian stenosis)
Negative temporal biopsy, high suspicion → skip lesions — still treat
Former GCA patient with a dilated ascending aorta → thoracic aortic aneurysm
Granulomas with giant cells in the aortic arch of a 25-year-old → Takayasu
Steroid-sparing biologic for GCA → tocilizumab (IL-6 receptor)