What are the diagnostic criteria for Takayasu arteritis?

Diagnostic Criteria for Takayasu Arteritis

The diagnosis of Takayasu arteritis requires meeting at least 3 of the 6 American College of Rheumatology 1990 criteria: age of onset <40 years, intermittent claudication, diminished brachial artery pulse, systolic blood pressure difference >10 mmHg between arms, subclavian/aortic bruit, and angiographic evidence of aorta or branch vessel stenosis. 1, 2

American College of Rheumatology 1990 Criteria

When 3 or more of the following 6 criteria are present, the sensitivity is 90.5% and specificity is 97.8% for diagnosis:

1. Age of onset younger than 40 years
2. Intermittent claudication of extremities
3. Decreased brachial artery pulse
4. Systolic blood pressure difference >10 mmHg between arms
5. Bruit over subclavian arteries or aorta
6. Angiographic evidence (CT, MRI) of stenosis or occlusion of the aorta or its primary branches 1, 2

Supporting Laboratory Tests

• Inflammatory markers are important but not part of formal diagnostic criteria:
  • Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are elevated in approximately:
    • 70% of patients in the acute phase
    • 50% of patients in the chronic phase 1

Imaging for Diagnosis

• Initial evaluation should include thoracic aorta and branch vessel imaging:
  • CT angiography (CTA) or MR angiography (MRA) to investigate aneurysm or occlusive disease 1, 3
  • Characteristic findings include:
    • Narrowing of arterial lumen
    • Circumferential soft tissue thickening of vessel walls
    • Stenosis or occlusion of the aorta and its major branches 1, 4

Clinical Phases and Presentations

Takayasu arteritis typically develops in two phases:

1. Acute phase:

   • Constitutional symptoms ("B" symptoms): weight loss, fatigue, night sweats, anorexia, malaise 1

2. Chronic phase:

   • Vascular symptoms related to affected organs:
     • Upper extremity claudication (>50% of patients)
     • Cerebrovascular insufficiency: vision loss, lightheadedness, stroke (50% of patients)
     • Carotid artery pain (one-third of patients)
     • Hypertension (common in Indian-type distribution) 1, 3

Disease Distribution Patterns

• Japanese distribution: Primarily affects thoracic aorta and great vessels
• Indian distribution: Primarily affects abdominal aorta and renal arteries 1, 3

Vascular Complications

• Stenosis: More common (53% of patients), predominantly affecting abdominal aorta (>70% of cases)
• Aneurysm: Less common (23-32% of patients), can affect descending aorta, abdominal aorta, aortic arch, or root 1

Important Clinical Considerations

• Takayasu arteritis affects women approximately 10 times more often than men 1, 3
• Although initially described in Japan, the disease is found worldwide and affects all ethnic groups 1, 5
• Diagnosis is often delayed due to nonspecific initial symptoms 6
• Physical examination should focus on vascular findings: pulse deficits, bruits, and blood pressure differentials 3

The diagnosis of Takayasu arteritis requires a high index of suspicion, especially in young women presenting with constitutional symptoms and vascular abnormalities. The combination of clinical criteria, laboratory markers, and imaging findings provides the most accurate diagnostic approach.