What is the recommended workup and treatment for a patient suspected of having large vessel vasculitis?

Workup for Large Vessel Vasculitis

Immediate Clinical Assessment

When large vessel vasculitis (LVV) is suspected, initiate high-dose glucocorticoids (40-60 mg/day prednisone) immediately based on clinical suspicion alone, before imaging confirmation, to prevent irreversible complications such as blindness in giant cell arteritis (GCA) or vascular ischemia. 1

Key Clinical Features to Identify

For Giant Cell Arteritis (age ≥50 years): 1

• New-onset temporal headache, scalp tenderness, jaw claudication 1
• Visual symptoms (amaurosis fugax, diplopia, acute vision loss) 1
• Tenderness or thickening of temporal arteries with reduced pulsation 1
• Constitutional symptoms (fever, weight loss >2 kg, fatigue, night sweats) 1
• Bruits over axillary arteries, reduced upper limb pulses or blood pressure discrepancy 1

For Takayasu Arteritis (typically age <40 years): 1, 2

• Hypertension (>140/90 mmHg), particularly renovascular hypertension 1, 2
• New loss of pulses, pulse inequality between extremities 1, 2
• Vascular bruits over subclavian arteries or aorta 1, 2
• Blood pressure discrepancy >10 mmHg between arms 2
• Constitutional symptoms followed by vascular manifestations (biphasic presentation) 2
• Limb claudication, stroke, syncope, myocardial infarction 1

Diagnostic Confirmation Strategy

Laboratory Testing

Obtain inflammatory markers immediately, recognizing their limitations: 1

• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are elevated in most GCA cases, but normal ESR/CRP should raise suspicion for alternative diagnosis in suspected GCA 1
• In Takayasu arteritis, inflammatory markers are elevated in only 50% of cases and cannot be relied upon solely for diagnosis or disease activity assessment 2

Imaging Workup

The diagnostic approach differs based on suspected disease subtype:

For suspected predominantly cranial GCA: 1

• First-line: Ultrasound of temporal ± axillary arteries showing non-compressible "halo" sign (77% sensitive, 96% specific) 1
• Alternative if ultrasound unavailable or inconclusive: High-resolution MRI of cranial arteries to detect mural inflammation 1
• CT and PET are not recommended for cranial artery assessment 1

For suspected large vessel GCA or Takayasu arteritis: 1, 2

• First-line for Takayasu arteritis: MRI/MRA to investigate mural inflammation and luminal changes (stenosis, occlusion, aneurysm) 1, 2
• Alternative modalities: PET-CT (shows supraphysiologic FDG uptake in active disease), CT/CTA, or ultrasound for extracranial vessels 1, 2
• Ultrasound has limited value for thoracic aorta assessment 1
• Conventional angiography is not recommended as it has been superseded by cross-sectional imaging 1

Critical timing considerations: 1

• Imaging should not delay initiation of glucocorticoid therapy 1
• Temporal artery biopsy (if performed) should not be delayed beyond 1-2 weeks after starting glucocorticoids 1
• Biopsy specimens must be ≥1 cm in length (≥0.7 cm post-fixation) for adequate diagnostic yield 1

Diagnostic Confirmation Algorithm

High clinical probability + positive imaging = diagnosis confirmed without additional testing 1

Low clinical probability + negative imaging = diagnosis unlikely 1

All other scenarios require additional diagnostic efforts (alternative imaging modality, temporal artery biopsy for GCA, or referral to expert center) 1

Urgent Referral Criteria

All patients with suspected GCA require urgent referral to a specialist team for multidisciplinary diagnostic workup 1

All patients with suspected Takayasu arteritis require referral to an experienced center due to disease rarity, need for specialized imaging and vascular surgery expertise, and treatment complexity 1, 2

Life-threatening presentations requiring immediate specialist involvement: 1

• Acute vision loss, amaurosis fugax, or diplopia 1
• Stroke, seizures, syncope 1
• Myocardial infarction, angina 1
• Critical limb ischemia 1

Initial Treatment Pending Confirmation

Initiate high-dose oral prednisone 40-60 mg/day (or 1 mg/kg/day, maximum 60-80 mg) immediately upon clinical suspicion 1

For GCA with acute vision loss or amaurosis fugax: 1, 3

• Consider intravenous methylprednisolone 0.25-1 g/day for 3 consecutive days, followed by oral prednisone 60 mg/day 1, 3
• However, do not delay oral glucocorticoid treatment while arranging IV access 1, 3
• Evidence supporting IV pulse therapy is limited to low-quality retrospective data 1, 3

For Takayasu arteritis: 1, 2, 4

• Initiate high-dose oral glucocorticoids (40-60 mg/day prednisone) plus a non-glucocorticoid immunosuppressive agent (preferably methotrexate 20-25 mg/week) simultaneously 1, 2, 4
• Do not use glucocorticoid monotherapy except in mild or diagnostically uncertain cases 2, 4

Monitoring Protocol After Diagnosis

Establish baseline assessment with four-extremity blood pressures, complete vascular examination, and cross-sectional imaging 2

Schedule regular follow-up imaging: 2

• Every 3-6 months during active disease 2
• Extended intervals for established quiescent disease, but maintain lifelong monitoring given catastrophic potential outcomes 2
• MRA or CTA for long-term structural damage monitoring (stenosis, occlusion, aneurysm formation) 1, 2

At each clinical visit: 2

• Four-extremity blood pressures 2
• Vascular examination for new bruits or pulse deficits 2
• Assessment for clinical signs/symptoms of active disease 2
• Inflammatory markers (ESR, CRP), recognizing they are imperfect indicators 2

Common Pitfalls to Avoid

Do not wait for imaging confirmation before starting glucocorticoids in high clinical suspicion cases 1

Do not rely solely on normal inflammatory markers to exclude LVV, particularly in Takayasu arteritis where ESR/CRP are normal in 50% of active cases 1, 2

Do not use catheter angiography for routine diagnosis or monitoring, as it only shows luminal changes and misses wall inflammation 2

Do not perform temporal artery biopsy >2 weeks after glucocorticoid initiation, as diagnostic yield decreases 1

Do not discontinue monitoring in clinical remission, as vascular changes occur when disease appears quiescent 2