A 58-year-old man with a 3-day history of acute dyspnea and pleuritic chest pain presents to the emergency department. He has been immobilized for 10 days following a femoral fracture. Vital signs: HR 110/min, BP 128/82 mmHg, RR 24/min, SpO₂ 92% on room air. Chest X-ray is normal. ECG shows sinus tachycardia. Which is the most appropriate next step in management?

Explanation

## Clinical Context This patient has a high pretest probability of pulmonary embolism (PE): immobilization (major risk factor), acute dyspnea, pleuritic chest pain, tachycardia, and hypoxemia. The normal chest X-ray and ECG do not exclude PE. ## Diagnostic Approach in High-Probability Patients **Key Point:** In patients with high clinical suspicion for PE, imaging confirmation (CTPA) should be obtained before or immediately upon starting anticoagulation. **High-Yield:** The Wells score or revised Geneva score can stratify risk, but in this case the clinical picture is sufficiently concerning that imaging is warranted without delay. ## Why CTPA is the Next Step 1. **Confirmatory imaging** — CTPA is the gold standard for PE diagnosis when clinical suspicion is high 2. **Guides treatment intensity** — Confirms PE presence and helps assess severity (RV dysfunction, hemodynamic impact) 3. **Timing** — Should be obtained urgently (within hours) in suspected PE with hemodynamic compromise or significant hypoxemia 4. **Avoids unnecessary anticoagulation** — Confirms diagnosis before committing to long-term anticoagulation and its bleeding risks **Clinical Pearl:** While anticoagulation may be started empirically in some high-risk scenarios (e.g., massive PE with hemodynamic collapse), in a stable patient with moderate-to-high suspicion, diagnostic confirmation via CTPA is standard practice. ## Management Algorithm ```mermaid flowchart TD A[Suspected PE: High clinical probability]:::outcome --> B{Hemodynamically stable?}:::decision B -->|Yes| C[Obtain CTPA]:::action B -->|No| D[Start anticoagulation empirically]:::urgent C --> E{PE confirmed?}:::decision E -->|Yes| F[Anticoagulation + supportive care]:::action E -->|No| G[Investigate alternative diagnosis]:::action D --> H[CTPA when stable enough]:::action ``` **Tip:** Remember that D-dimer is useful for ruling out PE in low-probability patients; it is not helpful in high-probability cases and should not delay imaging.