Temporal (Giant Cell GCA) Arteritis ✅

Related Subjects: | Temporal (Giant Cell GCA) Arteritis | Tocilizumab

🩺 Giant Cell Arteritis (GCA) is a large-vessel vasculitis and an ophthalmological emergency. ⚠️ Can cause irreversible blindness (20% of cases) but preventable if diagnosed and treated promptly. Commonly encountered in rheumatology, ophthalmology, and stroke/TIA clinics.

🚨 Ophthalmological Emergency – Immediate Actions

• 👵 Age >50 with new headache, tender/pulseless temporal arteries, ↑ ESR/CRP.
• 💊 Start Prednisolone 1 mg/kg PO immediately + PPI for gastroprotection. Do not delay for biopsy.
• 🔬 Confirm with temporal artery biopsy (TAB) or duplex US (“halo sign”).
• 🦴 Provide bone protection: bisphosphonate, calcium, vitamin D.
• 👨‍⚕️ Urgent referral to Rheumatology/Ophthalmology.
• 🧬 Tocilizumab (IL-6R inhibitor) for steroid-sparing in relapsing/refractory cases.

💡 Tocilizumab: Humanised monoclonal antibody targeting IL-6 receptor. Weekly SC injection; reduces relapse and steroid burden.

ℹ️ About GCA

• 🎯 Large/medium artery vasculitis, especially branches of the external carotid (temporal, ophthalmic, ciliary, retinal).
• 👁️ Blindness risk due to anterior ischaemic optic neuropathy from posterior ciliary artery occlusion.
• 🧑‍🦳 ~50% overlap with Polymyalgia Rheumatica (PMR).

📊 Epidemiology

• Mean age ~70 yrs; rare <50.
• ♀:♂ ratio ≈ 3:1.
• Predominantly Northern European/Caucasian populations.

🔎 Phenotypes

• 🧠 Cranial GCA: headache, scalp tenderness, jaw claudication, visual loss.
• 🫀 Extracranial GCA: limb claudication, systemic features, aortic involvement.
• ⚖️ Mixed: combination of cranial and extracranial features.

🩸 Vessels Involved

• Posterior ciliary arteries → AION → blindness.
• Central retinal artery → sudden visual loss.
• Extraocular muscle ischaemia → diplopia.
• Aorta → late aneurysm or dissection.

🧬 Pathogenesis

• Immune response to unknown antigen → chronic granulomatous inflammation with giant cells.
• Th1-mediated inflammation; IL-6 central to pathophysiology.
• HLA-DRB1 alleles increase susceptibility.

📋 ACR Diagnostic Criteria (≥3/5 = GCA)

🩺 Clinical Presentation

• 🌡️ Systemic: fever, malaise, weight loss, fatigue.
• 👁️ Visual: transient/monocular visual loss, AION, diplopia.
• 🧠 Headache: abrupt, often temporal/occipital.
• 🖐️ Temporal artery: tender, thickened, pulseless.
• 🦷 Jaw claudication = highly specific.
• 📉 Complications: blindness, aortitis, aortic aneurysm/dissection (late).

🔬 Investigations

• 🩸 FBC: normocytic anaemia, thrombocytosis.
• 🔥 ESR >50, CRP elevated; ALP ↑ in ~30%.
• 🖥️ Duplex US: halo sign (resolves after steroids).
• 🔬 Temporal artery biopsy: gold standard; skip lesions common, ideally <2 weeks after steroids.
• 👁️ Fluorescein angiography: choroidal hypoperfusion.

💊 Management

• 👁️ Visual symptoms: high-dose steroids (Prednisolone 1 mg/kg PO or IV methylprednisolone 500–1000 mg × 3 days), urgent ophthalmology input.
• Non-visual symptoms: oral steroids + rheumatology follow-up.
• ⏳ Taper steroids slowly over 18–24 months; monitor relapses.
• 🧬 Tocilizumab: weekly SC 162 mg; steroid-sparing for relapsing/refractory disease.
• 🦴 Bone protection: calcium/vitamin D ± bisphosphonate, cardiovascular risk mitigation, glucose monitoring.

📚 References

• Hassan N et al. Giant Cell Arteritis. BMJ 2011;342:d3019.
• NICE Guideline: Vasculitis (ANCA-associated & GCA)

Cases

Case 1 – Cranial GCA with visual risk: 71F, new unilateral temporal headache, scalp tenderness, jaw claudication, transient amaurosis fugax. Exam: tender, thickened temporal artery, RAPD. CRP 78, ESR 92. Immediate high-dose steroids + PPI, bone protection, ophthalmology review, urgent temporal artery US/biopsy, slow taper under rheumatology.

Case 2 – PMR phenotype with systemic symptoms: 68M, 4 weeks shoulder/hip girdle pain, low-grade fever, dull headache. CRP 56, ESR 70. Start prednisolone 40 mg PO same day; arrange temporal artery US ± biopsy, consider large-vessel imaging (CTA/MRA), bone protection, monitor steroid toxicity, steroid-sparing if relapsing.

Case 3 – Pure PMR: 73F, bilateral shoulder/hip pain >60 min morning stiffness, no headache/jaw/visual symptoms. Labs: CRP 48, ESR 62. Prednisolone 12.5–15 mg PO with taper; bone protection, safety-net advice for GCA red flags, consider methotrexate if relapsing or steroid-intolerant.