What is the recommended workup and treatment for a patient suspected of having large vessel vasculitis, such as Takayasu's arteritis?

Workup for Large Vessel Vasculitis (Takayasu Arteritis)

When Takayasu arteritis is suspected, immediately initiate high-dose oral glucocorticoids (40-60 mg/day prednisone) while simultaneously pursuing diagnostic confirmation through comprehensive arterial imaging (MRI/CT angiography or PET-CT) combined with clinical examination of the entire arterial tree. 1, 2

Clinical Recognition and Initial Assessment

Key Clinical Features to Identify

Constitutional symptoms that should raise suspicion include:

• Weight loss >2 kg, low-grade fever, fatigue, night sweats 1
• New onset or worsening limb claudication 1
• Myalgia, arthralgia, or arthritis 1

Vascular manifestations on examination:

• Hypertension (>140/90 mm Hg) 1
• New loss of pulses or pulse inequality between extremities 1
• Blood pressure discrepancy >10 mmHg between arms 2
• Vascular bruits over subclavian arteries, axilla, or aorta 1, 2
• Carotidynia (tenderness over carotid arteries) 1
• Diminished or absent peripheral pulses 2

Life-threatening presentations requiring urgent evaluation:

• Stroke, seizures (non-hypertensive), syncope, dizziness 1
• Myocardial infarction or angina 1
• Severe abdominal pain 1
• Acute visual symptoms (amaurosis fugax, diplopia) 1
• Paresis of extremities 1

Four-Extremity Blood Pressure Measurement

Obtain blood pressures in all four extremities at initial assessment and every follow-up visit to detect asymmetry and monitor for new stenoses 2

Laboratory Evaluation

Essential Initial Tests

Inflammatory markers:

• ESR and CRP should be measured, though they are elevated in only 50% of active cases and are imperfect indicators of disease activity 2, 3
• Normal inflammatory markers do NOT exclude active disease 2

Complete blood count with differential:

• Assess for anemia, leukocytosis, thrombocytosis indicating active inflammation 3

Comprehensive metabolic panel:

• Serum creatinine to evaluate renal function, as renal artery involvement can cause hypertension and renal insufficiency 3

Urinalysis:

• Screen for hematuria and proteinuria at every visit 3

Important caveat: Do not rely on inflammatory markers alone for diagnosis or disease activity assessment—they can be normal in active disease and elevated due to infection or other causes 2, 3

Imaging Strategy

First-Line Diagnostic Imaging

MRI/MRA or CT angiography is the preferred initial imaging modality for Takayasu arteritis:

• MRI is considered first choice for suspected Takayasu arteritis by EULAR 4
• CT angiography is most commonly used for initial diagnosis (58.8% of cases) 2
• MR angiography is preferred for follow-up monitoring (62.3% of cases) 2
• These modalities provide information about vascular wall inflammation, not just luminal changes 2

PET-CT (FDG-PET):

• Can assist in documenting arterial involvement and assessing disease activity 1, 2
• Shows supraphysiologic FDG uptake in active disease 2
• Requires formal validation but is increasingly used 1, 2

Ultrasound:

• Limited evidence for carotid and subclavian ultrasonography in Takayasu arteritis monitoring 1
• Less commonly used than in giant cell arteritis 4

When to Use Conventional Angiography

Reserve catheter angiography for:

• Determining central blood pressures 2
• Surgical planning 2
• When noninvasive modalities are inadequate 2

Important limitation: Conventional angiography only shows luminal changes and misses wall inflammation, making it inferior for disease activity assessment 2

Imaging Findings Indicating Active Disease

• Vascular edema on MRI 2
• Contrast enhancement of vessel walls 2
• Increased wall thickness on MR/CT angiography 2
• Supraphysiologic FDG uptake on PET 2
• New arterial stenosis or vessel wall thickening in new territories 2

Diagnostic Confirmation

A suspected diagnosis must be confirmed by imaging demonstrating:

• Aortic or branch vessel stenosis, occlusion, or aneurysm 1, 2
• Arterial wall thickening or enhancement 1, 2
• Pattern consistent with large vessel vasculitis affecting aorta and major branches 2

Thorough arterial tree assessment should include:

• Thoracic and abdominal aorta 2
• Carotid arteries 2
• Subclavian arteries 2
• Renal arteries 2
• Mesenteric vessels 2

Referral pathway:

• All patients with suspected Takayasu arteritis should be referred to an experienced center for multidisciplinary diagnostic workup and management 1, 2
• Patients with presentations suggesting increased risk of ischemic complications need urgent referral 1

Immediate Treatment Initiation

Do Not Delay Treatment While Awaiting Imaging

Start high-dose oral glucocorticoids immediately (40-60 mg/day prednisone-equivalent) when clinical suspicion is high, even before imaging confirmation 1, 2

Rationale for immediate treatment:

• Prevents irreversible ischemic complications 1
• Imaging can still show features of vasculitis even weeks after glucocorticoid initiation 1
• Sensitivity of diagnostic tests decreases with treatment, but confirmation remains possible 1

Simultaneous immunosuppression:

• Add a non-glucocorticoid immunosuppressive agent (preferably methotrexate 20-25 mg/week) at diagnosis to minimize glucocorticoid toxicity 2
• Do not use glucocorticoid monotherapy except for mild or uncertain cases 2

Special Circumstances Requiring IV Pulse Glucocorticoids

Reserve IV methylprednisolone (500-1,000 mg/day for 3-5 days) for:

• Life-threatening manifestations (stroke, cardiac ischemia) 2
• Organ-threatening disease (vision loss, limb ischemia) 2
• IV pulse therapy is NOT superior to high-dose oral glucocorticoids for routine cases 2

Monitoring Protocol After Diagnosis

Imaging Schedule

During active disease:

• Perform noninvasive imaging every 3-6 months 2
• Continue regular imaging even when disease appears clinically quiescent, as vascular changes can occur without symptoms 2

In established quiescent disease:

• Extend imaging intervals but maintain long-term monitoring 2
• All patients require lifelong monitoring given catastrophic potential outcomes 1, 2

Clinical Monitoring at Each Visit

• 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) alongside clinical assessment 1, 2
• Urinalysis to screen for infection or renal involvement 3

Critical pitfall to avoid: Do not discontinue monitoring in clinical remission—vascular progression occurs when disease appears quiescent 2

Differential Diagnosis Considerations

Age is the most critical distinguishing feature:

• Takayasu arteritis predominantly affects women under 40 years 2
• Giant cell arteritis typically affects patients over 50 years 2

Other conditions to consider:

• Giant cell arteritis (older patients, temporal artery involvement) 2
• Fibromuscular dysplasia 2
• Aortic coarctation 2
• Behçet disease (involves both arteries and veins, unlike Takayasu which is arterial only) 2
• Other large vessel vasculitides 2