What are the signs of a pulmonary embolism?

Signs of Pulmonary Embolism

Pulmonary embolism presents with highly non-specific signs and symptoms, including dyspnea, chest pain, pre-syncope or syncope, and hemoptysis, which can mimic many other cardiac or pulmonary conditions. 1

Common Clinical Presentations

Respiratory Symptoms

• Dyspnea: Most common symptom (80-89% of cases), may be acute and severe in central PE or mild and transient in peripheral PE 1, 2
• Hemoptysis: Less common but specific sign of pulmonary infarction 1
• Pleuritic chest pain: Occurs in 40-60% of patients, typically caused by pleural irritation from distal emboli 1, 2

Cardiovascular Signs

• Tachycardia: Present in approximately 40% of patients 1
• Syncope or pre-syncope: Associated with higher prevalence of hemodynamic instability and right ventricular dysfunction 1
• Hypotension or shock: Rare but important presentation indicating central or extensive PE with severely reduced hemodynamic reserve 1

ECG Findings

• Right ventricular strain patterns:
  • Inversion of T waves in leads V1-V4
  • QR pattern in V1
  • S1Q3T3 pattern (S wave in lead I, Q wave and inverted T wave in lead III)
  • Incomplete or complete right bundle branch block 1
• Atrial arrhythmias: Particularly atrial fibrillation 1

Physical Examination

• Often unremarkable in small to moderate PE
• Tachypnea
• Signs of deep vein thrombosis (unilateral leg swelling, pain)
• Elevated jugular venous pressure
• Accentuated pulmonary component of second heart sound
• Right ventricular heave (in severe cases) 1

Laboratory and Imaging Findings

Blood Tests

• Hypoxemia: Common but not universal (≤40% of patients have normal arterial oxygen saturation) 1
• Hypocapnia: Often present 1
• D-dimer: Elevated in acute PE but has low specificity (approximately 50%) 2

Chest X-ray

• Frequently abnormal but findings are non-specific
• May show:
  • Atelectasis
  • Pleural effusion
  • Elevated hemidiaphragm
  • Pulmonary infiltrates
  • Hampton's hump (wedge-shaped peripheral opacity)
  • Westermark sign (focal oligemia) 1

Echocardiographic Signs

• Right ventricular dilation (RV/LV ratio >1.0)
• McConnell sign (hypokinesia of RV free wall with normal RV apex)
• Flattened interventricular septum
• Distended inferior vena cava with diminished inspiratory collapsibility
• Tricuspid regurgitation
• Pulmonary hypertension 1

Risk Stratification

PE severity should be assessed based on:

1. Hemodynamic status: Presence of shock or hypotension indicates high-risk PE 1
2. Right ventricular function: Evidence of RV dysfunction on imaging suggests intermediate-high risk 1
3. Clinical prediction scores: Wells score or revised Geneva score help determine pre-test probability 2

Common Pitfalls in Diagnosis

• Non-specific presentation: PE symptoms overlap with many other cardiopulmonary conditions 3
• Variable clinical picture: Presentation ranges from asymptomatic to cardiovascular collapse 4
• Co-existing conditions: PE frequently coexists with conditions it mimics 3
• Normal vital signs: Some patients with PE may have normal oxygen saturation and vital signs 1
• Relying solely on clinical impression: No single symptom or sign has sufficient sensitivity or specificity to rule in or rule out PE 2

Key Points for Early Recognition

• Maintain high clinical suspicion in patients with risk factors (recent surgery, trauma, malignancy, estrogen exposure, immobility) 5
• Consider PE in any patient with unexplained dyspnea, chest pain, or syncope 6
• Use structured clinical prediction tools to guide diagnostic approach 2
• Remember that PE can present with minimal symptoms despite significant clot burden 7

Early recognition of these signs and appropriate diagnostic workup are crucial for reducing mortality and morbidity associated with pulmonary embolism.