What are the signs and symptoms of pulmonary embolism (PE)?

Signs and Symptoms of Pulmonary Embolism (PE)

Pulmonary embolism presents with dyspnea (80% of cases), chest pain (52%), and syncope (19%), with at least one of these symptoms present in 97% of patients with PE. 1

Common Clinical Presentations

Primary Symptoms

• Dyspnea: Most common symptom (80% of cases)

  • May be acute and severe in central PE
  • May be mild and transient in peripheral PE
  • In patients with pre-existing heart failure or pulmonary disease, worsening dyspnea may be the only symptom 2

• Chest Pain: Present in 52% of cases

  • Pleuritic chest pain: Caused by pleural irritation due to distal emboli causing pulmonary infarction
  • Angina-like retrosternal pain: May reflect right ventricular ischemia in central PE 2

• Syncope: Present in 19% of cases

  • Important warning sign as it may indicate severely reduced hemodynamic reserve
  • Associated with higher prevalence of hemodynamic instability and RV dysfunction 2, 1

Other Common Symptoms

• Hemoptysis: Results from alveolar hemorrhage in pulmonary infarction 2
• Pre-syncope: Feeling of lightheadedness without complete loss of consciousness 2

Physical Examination Findings

Vital Signs

• Tachypnea (>20 breaths/min): Present in 70% of cases 1
• Tachycardia (>100 beats/min): Present in 26% of cases 1
• Hypotension: Systolic BP <90 mmHg or drop ≥40 mmHg lasting >15 minutes (indicates high-risk PE) 2
• Fever: Present in 7% of cases 1

Other Physical Findings

• Signs of deep vein thrombosis (unilateral leg swelling, pain): Present in 15% of cases 1
• Signs of right ventricular failure: Elevated jugular venous pressure, right-sided S3 gallop, tricuspid regurgitation murmur

Laboratory and Imaging Findings

• Hypoxemia: Present in 75% of cases, though up to 40% may have normal arterial oxygen saturation 1
• Hypocapnia: Often present 2
• ECG findings: Signs of RV strain such as:
  • T-wave inversion in leads V1-V4
  • QR pattern in lead V1
  • S1Q3T3 pattern
  • Right bundle branch block 2

Severity Classification

PE can be classified based on risk of early mortality:

1. High-risk PE (Massive):

   • Presents with shock or persistent arterial hypotension
   • Systolic BP <90 mmHg or requiring vasopressors
   • May require cardiopulmonary resuscitation
   • Associated with >15% short-term mortality 2

2. Intermediate-risk PE (Submassive):

   • Hemodynamically stable but with right ventricular dysfunction and/or myocardial injury
   • Short-term mortality 3-15% 2, 1

3. Low-risk PE:

   • Hemodynamically stable without RV dysfunction
   • Short-term mortality <1% 2, 1

Important Clinical Pitfalls

• Normal oxygen saturation does not exclude PE: Up to 40% of patients may have normal arterial oxygen saturation 1
• Absence of risk factors: In approximately 30% of cases, PE occurs without any identifiable predisposing factors 2
• Variable symptom onset: Dyspnea onset can be acute or gradually progressive over several weeks 2
• Non-specific chest X-ray findings: Common findings (plate-like atelectasis, pleural effusion, elevated hemidiaphragm) are non-specific 2
• Asymptomatic presentation: Some cases may be asymptomatic or discovered incidentally 2

When to Suspect PE

PE should be suspected in any patient presenting with:

1. Unexplained dyspnea, especially of sudden onset
2. Pleuritic chest pain without other obvious cause
3. Syncope without alternative explanation
4. Worsening of pre-existing dyspnea in patients with heart failure or pulmonary disease
5. Hypoxemia disproportionate to the degree of dyspnea
6. Presence of risk factors for venous thromboembolism (recent surgery, trauma, immobilization, cancer, pregnancy, oral contraceptive use)

Early recognition of these signs and symptoms is crucial for prompt diagnosis and treatment to reduce PE-related mortality, which can be as high as 8-15% in the first 3 months after diagnosis 1.