What is the diagnostic approach for a young woman with suspected Takayasu arteritis, presenting with symptoms of vascular insufficiency, fever, and fatigue?

Diagnosis of Takayasu Arteritis

Diagnose Takayasu arteritis through a combination of clinical findings (diminished pulses, blood pressure discrepancy >10 mmHg between arms, vascular bruits), elevated inflammatory markers in 50% of cases, and confirmatory noninvasive vascular imaging (CT angiography, MR angiography, or FDG-PET) demonstrating aortic or branch vessel stenosis, aneurysm, or characteristic wall inflammation. 1

Clinical Assessment

Key Physical Examination Findings

• Diminished or absent peripheral pulses are the hallmark finding that should immediately raise suspicion for Takayasu arteritis 1
• Blood pressure discrepancy >10 mmHg between arms is a critical diagnostic clue—measure four-extremity blood pressures at initial evaluation 1
• Vascular bruits over subclavian arteries or aorta are characteristic findings on auscultation 1
• Constitutional symptoms including fever, fatigue, weight loss, and night sweats often precede vascular manifestations in a biphasic presentation pattern 1

Demographics and Clinical Context

• Predominantly affects young women under 40 years of age, which is the most critical distinguishing feature from giant cell arteritis 1
• Symptoms of vascular insufficiency combined with systemic inflammation in this demographic should trigger immediate diagnostic workup 1

Laboratory Testing

Inflammatory Markers

• ESR and CRP should be measured but are elevated in only 50% of active cases—normal inflammatory markers do NOT exclude active disease 1, 2
• These markers are imperfect indicators of disease activity and should never be relied upon solely for diagnosis 1
• No specific diagnostic autoantibodies exist for Takayasu arteritis, making clinical and imaging findings paramount 1, 2

Imaging Strategy (First-Line Diagnostic Approach)

Preferred Initial Imaging

• CT angiography, MR angiography, or FDG-PET are first-line diagnostic modalities and should be performed immediately when Takayasu arteritis is suspected 1, 3
• MRI/CT angiography is most commonly used, with CT angiography used for diagnosis in 58.8% of cases and MR angiography preferred for follow-up in 62.3% 1
• These noninvasive modalities provide information about vascular wall inflammation, not just luminal changes, allowing earlier diagnosis 1, 4

Key Imaging Findings That Confirm Diagnosis

• Angiographic evidence of aortic or branch vessel stenosis is the key diagnostic criterion per American College of Rheumatology criteria 1
• Circumferential soft tissue thickening of arterial walls with luminal narrowing on CT/MRI 3
• Vascular wall edema, contrast enhancement, and increased wall thickness on MR/CT angiography indicate active disease 3
• Supraphysiologic FDG uptake on PET-CT documents arterial involvement and active inflammation 1, 3
• Aneurysm formation or occlusive disease in the aorta and major branches 1

Conventional Angiography

• Should NOT be used as first-line diagnostic imaging as it has been superseded by noninvasive modalities 3
• Only shows luminal changes and misses early wall inflammation 1
• Reserve for determining central blood pressures, surgical planning, or when noninvasive modalities are inadequate 1

Diagnostic Algorithm

Step 1: Clinical Suspicion

• Young woman (<40 years) presenting with vascular insufficiency symptoms, fever, and fatigue 1
• Perform thorough vascular examination: check four-extremity blood pressures, palpate all pulses, auscultate for bruits 1

Step 2: Laboratory Evaluation

• Measure ESR/CRP (recognizing they may be normal in 50% of cases) 1, 2
• No specific autoantibody testing is diagnostic 1, 2

Step 3: Confirmatory Imaging

• Immediately obtain CT angiography or MR angiography of thoracic aorta and branch vessels 1, 3
• Look for stenosis, occlusion, aneurysm, or wall thickening/enhancement 1, 3
• Consider FDG-PET if available to assess disease activity 1, 3

Step 4: Referral and Treatment Initiation

• If clinical suspicion is high, initiate high-dose oral glucocorticoids (40-60 mg/day prednisone) immediately, even before imaging confirmation, to prevent irreversible ischemic complications 1
• Refer to an experienced center for multidisciplinary diagnostic workup and management 1

Differential Diagnosis to Exclude

• Giant cell arteritis: typically affects patients >50 years old, whereas Takayasu arteritis affects those <40 years 1
• Aortic coarctation: congenital narrowing without inflammatory features 1
• Fibromuscular dysplasia: non-inflammatory arterial disease 1
• Behçet disease: one of the only vasculitides that commonly involves veins, unlike Takayasu arteritis which is purely arterial 1

Critical Pitfalls to Avoid

• Do not wait for elevated inflammatory markers to make the diagnosis—they are normal in 50% of active cases 1, 2, 5
• Do not rely on conventional angiography alone—it misses early wall inflammation and only shows luminal changes 1, 3
• Do not delay treatment if clinical suspicion is high—irreversible ischemic complications can occur while awaiting imaging 1
• Do not dismiss the diagnosis in patients with normal ESR/CRP—disease activity can be present with normal inflammatory markers 1, 5

Post-Diagnosis Monitoring Protocol

• Lifelong monitoring is mandatory given catastrophic potential outcomes 1
• Regular noninvasive imaging every 3-6 months during active disease, with longer intervals for quiescent disease 1, 3
• Four-extremity blood pressures at every visit 1
• Vascular examination for new bruits or pulse deficits 1
• ESR/CRP alongside clinical assessment (but never rely on these alone) 1