Giant Cell Arteritis (Temporal Arteritis)
Summary
Giant Cell Arteritis (GCA) is a systemic large and medium vessel vasculitis that predominantly affects the cranial branches of the aorta, particularly the temporal arteries. It is a medical emergency because untreated GCA causes permanent visual loss in 15-20% of patients. GCA almost exclusively affects individuals over 50 years (peak age 70-80) and is strongly associated with polymyalgia rheumatica (PMR). The classic presentation is new-onset headache, scalp tenderness, jaw claudication, and markedly elevated inflammatory markers (ESR greater than 50, often greater than 100). Immediate high-dose glucocorticoids (prednisolone 60mg or IV methylprednisolone if visual symptoms) must be started on clinical suspicion — do NOT wait for biopsy confirmation. Temporal artery biopsy remains the gold standard for diagnosis, though ultrasound (halo sign) is increasingly used. Tocilizumab is now used as a steroid-sparing agent for relapsing or refractory disease.
Key Facts
- Definition: Large/medium vessel granulomatous vasculitis affecting aortic branches, predominantly cranial arteries
- Age: Greater than 50 years (by definition); peak 70-80 years
- Sex: Female:Male 2-3:1
- Emergency: 15-20% risk of permanent blindness if untreated
- Key symptom: New-onset headache + scalp tenderness in patient greater than 50
- Specific sign: Jaw claudication (pain on chewing — 90% specificity)
- Inflammatory markers: ESR greater than 50 (often greater than 100), CRP elevated
- Treatment: Immediate high-dose prednisolone (60mg) or IV methylprednisolone if visual symptoms
Clinical Pearls
"Don't Wait for the Biopsy": If GCA is clinically suspected, START STEROIDS IMMEDIATELY. Biopsy remains positive for up to 2 weeks after steroids are started. Delay risks permanent blindness.
Jaw Claudication is Gold: Jaw claudication (pain in the jaw muscles when chewing that is relieved by rest) is approximately 90% specific for GCA. It is caused by ischaemia of the masseter muscles.
The PMR-GCA Spectrum: 50% of GCA patients have symptoms of PMR. 10-20% of PMR patients will develop GCA. Always ask about headache and visual symptoms in PMR.
Why This Matters Clinically
GCA is a true emergency. Once vision is lost, it rarely recovers. The key is high clinical suspicion in any patient over 50 with new headache, temporal symptoms, or unexplained raised inflammatory markers. Starting steroids immediately can prevent blindness.
Incidence & Prevalence
- Incidence: 15-25 per 100,000 in those greater than 50 years (higher in Northern Europe)
- Peak age: 70-80 years
- Lifetime risk: Approximately 1% for women, 0.5% for men
- Geographic variation: Higher in Scandinavian and Northern European populations
Demographics
| Factor | Details |
|---|---|
| Age | Always greater than 50 years (typically 70-80) |
| Sex | Female:Male 2-3:1 |
| Ethnicity | Most common in Caucasians; rare in Asian and African populations |
| Geography | Higher in Northern Europe, North America |
Risk Factors
Non-Modifiable:
- Age greater than 50 years
- Female sex
- Northern European ancestry
- Family history
- HLA-DR4 association
Modifiable:
| Risk Factor | Association |
|---|---|
| Smoking | Possible association |
| Prior PMR | 10-20% develop GCA |
| Infections | Possible trigger (varicella zoster, parvovirus) |
Mechanism
Step 1: Trigger (Possibly Infectious/Environmental)
- Unknown trigger activates dendritic cells in adventitia of large vessels
- Possible infectious triggers include varicella zoster virus
Step 2: T-Cell Mediated Immune Response
- Activated dendritic cells present antigens to CD4+ T-helper cells
- Th1 and Th17 cells release IFN-γ, IL-17, and other inflammatory cytokines
- Macrophages recruited and fuse to form multinucleated giant cells
Step 3: Granulomatous Inflammation
- Transmural inflammation centred on internal elastic lamina
- Giant cells (fused macrophages) attack elastic tissue
- Intimal proliferation causes luminal narrowing
Step 4: Ischaemic Complications
- Luminal stenosis or occlusion of affected arteries
- Temporal artery involvement: headache, scalp tenderness
- Ophthalmic artery: anterior ischaemic optic neuropathy (AION), central retinal artery occlusion (CRAO)
- Large vessel involvement: aortic aneurysm, limb claudication, stroke
Classification
| Type | Features |
|---|---|
| Cranial GCA | Classic presentation with headache, temporal artery involvement, visual symptoms |
| Large Vessel GCA | Aorta and major branches involved; may present without headache |
| Occult GCA | Raised inflammatory markers, constitutional symptoms, no classic cranial features |
Association with PMR
| Condition | Overlap |
|---|---|
| GCA with PMR | 40-50% of GCA patients have PMR symptoms |
| PMR progressing to GCA | 10-20% of PMR patients develop GCA |
| Clinical significance | Always screen PMR patients for headache, jaw claudication, visual symptoms |
Symptoms
Classic Presentation:
Visual Symptoms (EMERGENCY):
PMR Symptoms (if present):
Signs
General:
Head and Neck:
Eyes:
Red Flags
[!CAUTION] Red Flags — IMMEDIATE steroids required if:
- ANY visual symptoms (transient or permanent)
- Jaw claudication (highly specific for GCA)
- Temporal artery tenderness or reduced pulsation
- New headache in patient greater than 50 with raised ESR/CRP
- Diplopia
- Scalp necrosis (rare, late sign)
Structured Approach
General:
- Vital signs (low-grade fever possible)
- Assess for weight loss, malaise
Head and Neck:
- Inspect temporal arteries (both sides): visible swelling?
- Palpate: tenderness, thickening, reduced or absent pulsation
- Scalp tenderness
- Jaw claudication (ask to chew repeatedly)
Eyes:
- Visual acuity
- Pupillary reflexes (RAPD)
- Fundoscopy (pale swollen disc in AION)
- Eye movements (diplopia/restriction)
Musculoskeletal:
- Shoulder and hip range of motion (PMR assessment)
- Proximal muscle tenderness
Special Tests
| Test | Technique | Positive Finding | Clinical Significance |
|---|---|---|---|
| Temporal artery palpation | Palpate along course of STA | Tender, thickened, non-pulsatile | GCA likely |
| RAPD (swinging flashlight test) | Shine light from one eye to other | Pupil dilates on affected side | Optic nerve ischaemia |
| Jaw claudication test | Ask patient to chew for 1-2 minutes | Pain develops, relieved by rest | 90% specific for GCA |
| PMR screen | Assess shoulder/hip ROM and stiffness | Restricted, painful | Associated PMR |
First-Line (Urgent)
- ESR — Typically greater than 50; often greater than 100
- CRP — Elevated (correlates well with activity)
- FBC — Normocytic anaemia, thrombocytosis common
- LFTs — Raised ALP (30%)
Laboratory Tests
| Test | Expected Finding | Purpose |
|---|---|---|
| ESR | Greater than 50 (often greater than 100) | Key diagnostic marker |
| CRP | Elevated | More sensitive; rises and falls faster than ESR |
| FBC | Normocytic anaemia; thrombocytosis | Chronic inflammation |
| LFTs | Raised ALP | Hepatic involvement in systemic inflammation |
| U&Es | Usually normal | Baseline before steroids |
| Glucose | Baseline | Monitor during steroids |
Imaging
| Modality | Findings | Indication |
|---|---|---|
| Ultrasound temporal artery | "Halo sign" — hypoechoic wall thickening | First-line; rapid, non-invasive |
| Temporal artery biopsy | Granulomatous inflammation, giant cells, intimal proliferation | Gold standard; arrange within 2 weeks |
| CTA/MRA | Large vessel involvement (aorta, subclavian) | Suspected large vessel GCA |
| PET-CT | Vascular FDG uptake | Active large vessel vasculitis |
Temporal Artery Biopsy
Technique:
- Minimum 2 cm segment (skip lesions common)
- Positive result confirms diagnosis
- Negative does not exclude — sensitivity 50-80%
- Can remain positive up to 2 weeks after steroids started
Histology:
- Granulomatous inflammation centred on internal elastic lamina
- Multinucleated giant cells
- Intimal proliferation
- Fragmentation of internal elastic lamina
Diagnostic Criteria
1990 ACR Classification Criteria (≥3 of 5):
- Age at onset ≥50 years
- New headache
- Temporal artery abnormality (tenderness, reduced pulse)
- ESR ≥50
- Abnormal temporal artery biopsy
Sensitivity 93%, Specificity 91%
Management Algorithm
Immediate Management (Emergency)
HIGH Clinical Suspicion — Don't Wait for Biopsy:
| Presentation | Treatment |
|---|---|
| GCA without visual symptoms | Prednisolone 40-60mg PO daily |
| GCA WITH visual symptoms | IV Methylprednisolone 1g daily × 3 days → then oral prednisolone 60mg |
| Recent or evolving visual loss | Urgent ophthalmology + IV steroids |
Long-Term Steroid Therapy
Taper Schedule (Example — BSR Guideline):
- Prednisolone 40-60mg daily for 2-4 weeks (until symptoms resolve and markers normalise)
- Reduce by 10mg every 2 weeks until 20mg
- Reduce by 2.5mg every 2-4 weeks until 10mg
- Reduce by 1mg every 1-2 months thereafter
- Total duration: 1-2 years minimum (often longer)
Monitoring:
- ESR/CRP monthly initially, then less frequently
- Symptoms of relapse (headache, jaw claudication, visual symptoms, PMR symptoms)
- Steroid side effects (glucose, BP, bone health)
Adjunctive Therapy
| Drug | Dose | Purpose |
|---|---|---|
| Low-dose aspirin | 75mg daily | Reduces ischaemic events (BSR recommends) |
| Bisphosphonate | Alendronate 70mg weekly | Bone protection (long-term steroids) |
| Calcium + Vitamin D | 1000mg Ca / 800IU D3 daily | Bone protection |
| PPI | Omeprazole 20mg | GI protection (especially if on aspirin) |
Steroid-Sparing Agents
| Drug | Dose | Indication |
|---|---|---|
| Tocilizumab | 162mg SC weekly OR 8mg/kg IV monthly | Relapsing/refractory GCA; reduces steroid burden; NICE approved |
| Methotrexate | 15-25mg weekly | Alternative; less evidence than tocilizumab |
Disposition
- Urgent ophthalmology referral: Any visual symptoms
- Rheumatology referral: All patients for ongoing management
- Vascular surgery/radiology: If large vessel GCA suspected (aortic imaging)
- Follow-up: Initially 2-weekly, then monthly; taper over 1-2+ years
Immediate (Hours-Days)
| Complication | Incidence | Presentation | Management |
|---|---|---|---|
| Permanent visual loss | 15-20% if untreated | Sudden painless monocular vision loss | Immediate IV methylprednisolone |
| Stroke | 2-4% | Sudden neurological deficit | Acute stroke management |
Early (Weeks-Months)
- Disease relapse: Return of symptoms during taper; requires steroid dose increase
- Steroid side effects: Hyperglycaemia, hypertension, weight gain, mood changes, insomnia
- Second eye involvement: 25-50% risk if first eye affected and untreated
Late (Years)
- Aortic aneurysm: 10-20% of GCA patients; aortic aneurysm/dissection risk elevated
- Osteoporosis: From prolonged steroid therapy
- Cataracts, glaucoma: Steroid complications
- Diabetes mellitus: Steroid-induced
- Adrenal suppression: From prolonged steroids; taper slowly
Natural History
- Untreated: High risk of permanent bilateral blindness (15-20%)
- With steroids: Excellent symptom control; majority achieve remission
- Average treatment duration: 1-2 years; some require longer
Outcomes with Treatment
| Variable | Outcome |
|---|---|
| Remission with steroids | 90%+ |
| Relapse during taper | 40-50% |
| Permanent visual loss (treated) | Less than 5% if treated early |
| Duration of treatment | Median 2 years |
| Long-term aortic complications | 10-20% |
Prognostic Factors
Good Prognosis:
- Rapid diagnosis and treatment
- No visual symptoms at presentation
- Good response to steroids
- Tocilizumab use in relapsing disease
Poor Prognosis:
- Visual symptoms at presentation
- Delayed treatment
- Large vessel involvement
- Frequent relapses
- Steroid intolerance
Key Guidelines
- BSR/BHPR Guideline (2020) — Management of Giant Cell Arteritis. Recommends immediate steroids, aspirin, tocilizumab for relapse. BSR
- EULAR Recommendations (2018) — Imaging in large vessel vasculitis. Supports ultrasound as first-line. EULAR
- ACR 1990 Classification Criteria — Standard diagnostic criteria. ACR
Landmark Trials
GiACTA Trial (Stone et al. 2017) — Tocilizumab for GCA
- 251 patients randomised to tocilizumab vs placebo
- Key finding: Tocilizumab + short steroid taper superior to steroids alone for sustained remission (56% vs 14%)
- Clinical Impact: Tocilizumab now first-line steroid-sparing agent
Proven et al. (2002) — Visual outcomes in GCA
- Retrospective cohort
- Key finding: 25-50% of untreated patients with unilateral visual loss develop bilateral blindness
- Clinical Impact: Emphasises urgency of treatment
TABUL Study (Luqmani et al. 2016) — Ultrasound in GCA
- Pragmatic trial comparing ultrasound to biopsy
- Key finding: Ultrasound "halo sign" has 77% sensitivity, 96% specificity
- Clinical Impact: Supports ultrasound as first-line imaging modality
Evidence Strength
| Intervention | Level | Key Evidence |
|---|---|---|
| Immediate high-dose steroids | 4 | Expert consensus; ethical barrier to RCT |
| IV methylprednisolone for visual symptoms | 4 | Expert consensus |
| Tocilizumab | 1b | GiACTA RCT |
| Ultrasound "halo sign" | 2a | TABUL study |
| Low-dose aspirin | 2a | Observational studies |
What is Giant Cell Arteritis?
Giant Cell Arteritis (GCA), also called Temporal Arteritis, is an inflammation of the blood vessels, especially the arteries in your temples (the sides of your head). It mainly affects people over 50. The inflammation can reduce blood flow through these arteries, which can cause serious problems — including permanent blindness if not treated quickly.
Is it serious?
Yes, GCA is a medical emergency because of the risk to your vision. Without treatment, about 1 in 5 people with GCA will lose some or all of their sight. The good news is that treatment with steroids is very effective if started early — this is why doctors will often start treatment immediately if they suspect GCA, even before confirming the diagnosis with tests.
How is it treated?
- Steroids (prednisolone): High-dose steroid tablets are started immediately. If you have any problems with your vision, you may be given steroids through a drip first.
- Long-term treatment: You will need to take steroids for 1-2 years, gradually reducing the dose. This is to keep the inflammation under control and prevent it coming back.
- Bone protection: Because steroids can weaken bones over time, you will likely be given tablets to protect your bones.
- Aspirin: A low dose of aspirin is often recommended to help prevent blockages in the blood vessels.
- Newer treatments: A medication called tocilizumab can be used if the condition keeps coming back or if steroids are causing too many side effects.
What to expect
- Symptoms usually improve within days of starting steroids
- Blood tests (ESR and CRP) are used to monitor your condition
- You'll be followed up regularly and the steroid dose will be slowly reduced
- Relapses can happen, especially when reducing the dose — this is why tapering is done very slowly
When to seek help
See a doctor immediately (this is an emergency) if:
- You notice any change in your vision (blurred, double, or partial loss)
- You develop a new headache, especially if you're over 50
- You have pain in your jaw when chewing
- Your scalp feels tender
- You feel generally unwell with high inflammatory markers
Primary Guidelines
- Mackie SL, et al. British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis. Rheumatology (Oxford). 2020;59(3):e1-e23. PMID: 31970405
- Dejaco C, et al. EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice. Ann Rheum Dis. 2018;77(5):636-643. PMID: 29358285
Key Trials
- Stone JH, et al. Trial of Tocilizumab in Giant-Cell Arteritis (GiACTA). N Engl J Med. 2017;377(4):317-328. PMID: 28745999
- Luqmani R, et al. The Role of Ultrasound Compared to Biopsy of Temporal Arteries in the Diagnosis and Treatment of Giant Cell Arteritis (TABUL). Ann Rheum Dis. 2016;75(6):996-1002. PMID: 26888949
- Proven A, et al. Glucocorticoid therapy in giant cell arteritis: duration and adverse outcomes. Arthritis Rheum. 2003;49(5):703-708. PMID: 14558057
Further Resources
- Versus Arthritis GCA: versusarthritis.org/about-arthritis/conditions/giant-cell-arteritis
- NHS Giant Cell Arteritis: nhs.uk/conditions/temporal-arteritis
- RNIB (sight loss support): rnib.org.uk
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Giant Cell Arteritis is a medical emergency. If you suspect GCA or have any visual symptoms, seek immediate medical attention.