A 35-year-old woman with a history of recurrent oral and genital ulcers, ocular inflammation, and arthritis presents with acute chest pain and dyspnea. Chest X-ray shows a widened mediastinum. Which investigation is most appropriate to confirm the diagnosis of Behçet disease with vascular involvement?

Explanation

## Diagnosis: Behçet Disease with Vascular Involvement **Key Point:** CT angiography (CTA) of the thorax is the most appropriate investigation to confirm vascular involvement in Behçet disease, demonstrating thrombosis, aneurysms, or aortic involvement causing the widened mediastinum. ### Clinical Presentation of Behçet Disease The patient meets diagnostic criteria for Behçet disease: - Recurrent oral ulcers (mandatory criterion) - Recurrent genital ulcers - Ocular involvement (uveitis) - Arthritis (arthralgia/arthritis) - Vascular manifestations (chest pain, dyspnea, widened mediastinum) ### Vascular Manifestations in Behçet Disease | Manifestation | Frequency | Imaging Finding | |---------------|-----------|------------------| | **Venous thrombosis** | 25–40% | CTA: filling defect, collateral veins | | **Pulmonary artery involvement** | 5–10% | CTA: aneurysm, thrombosis, hemorrhage | | **Aortic involvement** | 2–5% | CTA: aneurysm, dissection, widened mediastinum | | **Coronary artery disease** | 1–5% | Coronary angiography (if indicated) | ### Why CTA is the Gold Standard for Vascular Involvement **High-Yield:** CTA with contrast is the imaging modality of choice for detecting and characterizing vascular complications in Behçet disease: 1. **Superior resolution** — visualizes thrombosis, aneurysms, and aortic involvement 2. **Mediastinal assessment** — explains the widened mediastinum (aortic aneurysm, thrombosis, or hemorrhage) 3. **Rapid acquisition** — critical in acute presentations with chest pain 4. **Guides management** — determines need for anticoagulation, immunosuppression, or surgery **Clinical Pearl:** Pulmonary artery involvement in Behçet disease is associated with poor prognosis and high mortality if not treated aggressively with immunosuppression. CTA is essential for early detection. ### Diagnostic Algorithm for Behçet Disease ```mermaid flowchart TD A[Recurrent oral ulcers + 2 of: genital ulcers, ocular, skin lesions]:::outcome --> B{Suspected Behçet?}:::decision B -->|Yes| C[Clinical diagnosis confirmed]:::outcome C --> D{Vascular symptoms?}:::decision D -->|Yes| E[CTA thorax/abdomen]:::action D -->|No| F[Pathergy test for confirmation]:::action E --> G[Thrombosis/aneurysm detected?]:::decision G -->|Yes| H[Immunosuppression + anticoagulation]:::action G -->|No| I[Continue monitoring]:::action ``` **Warning:** Do not delay CTA in a patient with chest pain and suspected vascular Behçet disease. Aortic involvement can lead to rupture and sudden death.