Granulomatous large-vessel vasculitis in patients >50, typically affecting the extracranial carotid branches (especially temporal arteries), causing headaches, jaw claudication, and risk of blindness.
Most common adult vasculitis and a true rheumatologic emergency due to risk of irreversible blindness without prompt treatment.
Usually an elderly patient (>50, often 70s) with new-onset unilateral temporal headache, scalp tenderness (pain when combing hair), and jaw claudication (jaw pain/fatigue when chewing). Often accompanied by fatigue, weight loss, low-grade fever, and ~50% have coexisting polymyalgia rheumatica (shoulder/hip girdle aching and morning stiffness).
Visual symptoms may appear: transient blurred vision or amaurosis fugax (brief monocular vision loss) or diplopia can precede sudden permanent vision loss (from anterior ischemic optic neuropathy) if not treated. On exam, the temporal artery may be tender, enlarged, or have a diminished pulse.
Laboratory: Markedly elevated ESR (often >50–100 mm/h) and CRP are classic; mild normocytic anemia and elevated platelets are common inflammatory markers. Liver enzymes (especially alkaline phosphatase) can be mildly elevated.
Large-vessel involvement beyond cranial arteries can occur: e.g., arm claudication or asymmetric blood pressures if subclavian/axillary arteries are affected, or chest/back pain from aortitis (risking aneurysm). However, these manifestations are often subtler than cranial symptoms.
If you suspect GCA (age >50 + typical symptoms or high ESR), start high-dose corticosteroids immediately – do NOT wait for tests. Prompt treatment (prednisone ~40–60 mg daily, or IV methylprednisolone if vision is threatened) can prevent permanent blindness.
Confirm diagnosis with a temporal artery biopsy as soon as possible (ideally within 1–2 weeks of starting steroids). Biopsy a long segment (>1 cm) because of skip lesions. Histology shows granulomatous inflammation with multinucleated giant cells in the artery wall.
Use temporal artery ultrasound as a rapid, noninvasive adjunct: a hypoechoic "halo sign" (thickened vessel wall) is suggestive of GCA. MRI/MRA or PET can also identify large-vessel inflammation (e.g., aortitis) especially if biopsy is negative but suspicion remains.
Differentiate from Takayasu arteritis: GCA occurs in older patients (>50) with predominantly cranial artery involvement, whereas Takayasu affects younger patients (<40) and involves the aortic arch and its branches ("pulseless disease" of upper extremities).
acute focal deficits or transient monocular blindness (amaurosis fugax) usually from embolic disease; no systemic inflammation (normal ESR)
Corticosteroids – high-dose prednisone (40–60 mg daily) as first-line; if visual symptoms, consider IV methylprednisolone. Start at diagnosis (or suspicion) to prevent optic nerve damage, then taper slowly over 6–12+ months (guided by symptoms and ESR).
Tocilizumab (IL-6 inhibitor) – often added for GCA to improve remission rates and spare steroids. It's FDA-approved for GCA and can be started alongside steroids, especially in relapsing or refractory cases (monitor for infection).
Low-dose aspirin – often recommended if no contraindications, as GCA can predispose to cranial ischemia; aspirin may reduce the risk of vision loss or stroke. Ensure bone protection (calcium/Vit D, consider bisphosphonate) and gastric protection (PPI) given prolonged high-dose steroid use.
Mnemonic: 50-50-50 – occurs after age 50, ESR is often >50, treat with high-dose (~50 mg) steroids. In any new headache over 50 with ESR >50, think temporal arteritis and start steroids.
GCA and polymyalgia rheumatica travel together – about half of GCA patients have PMR, and some patients with isolated PMR later develop GCA. Always ask about head/jaw symptoms in PMR patients (and vice versa).
Amaurosis fugax (transient vision loss) or diplopia in a patient with suspected GCA – this is an emergency warning sign. It often heralds impending permanent blindness; treat immediately with IV high-dose steroids.
Signs of aortic involvement in known GCA (new chest pain, unequal blood pressures, or aortic regurgitation murmur) – raise concern for aortic aneurysm/dissection. Urgently image the aorta (e.g., CT/MRI) if these appear.
Age ≥50 with new localized headache (± jaw claudication or visual changes) → suspect GCA; check ESR/CRP.
High suspicion (classic symptoms or ESR >> 50) → start high-dose prednisone immediately (don't wait for confirmation).
Temporal artery biopsy within 1–2 weeks of starting steroids to confirm (histology: intimal thickening, granulomas with giant cells, skip lesions).
Imaging: Temporal artery ultrasound can show the halo sign; MRI/MRA or PET can assess large vessels (useful if biopsy is negative or atypical presentation).
After diagnosis, continue steroids and taper slowly (monitor symptoms and ESR). Add tocilizumab for steroid-sparing if needed; monitor for relapse and complications (osteoporosis prophylaxis, etc.).
An older woman with unilateral throbbing temple headache, scalp tenderness, jaw pain when chewing, and episodic vision blurring → Giant cell (temporal) arteritis (high ESR, treat immediately with steroids to prevent blindness).
A 65‑year‑old man with polymyalgia rheumatica on low-dose prednisone develops a new headache and jaw claudication; ESR is 85 → suspect giant cell arteritis (PMR patient with new cranial symptoms = GCA until proven otherwise).
Case 1
A 72‑year‑old woman presents with a 2-month history of right-sided temporal headaches and scalp tenderness. She reports jaw pain after chewing and had one episode of transient vision loss in her right eye.
Case 2
A 66‑year‑old man with polymyalgia rheumatica (on low-dose prednisone) develops a new constant headache and double vision. On exam, he has tenderness over his left temple and a left temporal artery pulse that is diminished.
Ultrasound of the temporal artery showing a dark "halo" around the vessel (wall thickening) consistent with giant cell arteritis.
