What are the clinical symptoms and signs of pulmonary embolism?

Clinical Symptoms and Signs of Pulmonary Embolism

Dyspnea, chest pain, and syncope are the most common clinical presentations of pulmonary embolism (PE), with these symptoms present in up to 97% of patients with PE. 1 Recognition of these key symptoms is critical as PE is a potentially fatal disorder with a wide range of clinical presentations, from hemodynamic instability to completely asymptomatic cases.

Common Clinical Presentations

Symptoms

• Dyspnea: Most frequent symptom (80% of PE cases) 1

  • May be acute and severe in central PE
  • Can be mild and transient in peripheral PE
  • In patients with pre-existing heart or lung disease, worsening dyspnea may be the only symptom 1

• Chest Pain: Second most common symptom (52% of cases) 1

  • Pleuritic chest pain: Usually caused by distal emboli causing pleural irritation 1
  • Substernal angina-like pain: Often seen in central PE, may reflect right ventricular ischemia 1

• Syncope: Present in 19% of cases 1

  • Important warning sign as it may indicate central PE with severe hemodynamic compromise
  • May occur regardless of hemodynamic instability 1

• Other symptoms:

  • Cough (20% of cases)
  • Hemoptysis (11% of cases)
  • Signs of deep vein thrombosis (15% of cases) 1

Signs

• Tachypnea (respiratory rate >20/min): Present in 70% of cases 1
• Tachycardia (heart rate >100/min): Present in 26% of cases 1
• Fever (>38.5°C): Present in 7% of cases (less common than in patients without PE) 1
• Cyanosis: Present in 11% of cases 1
• Signs of hemodynamic instability in severe cases:
  • Systemic arterial hypotension
  • Oliguria
  • Cold extremities
  • Signs of acute right heart failure 1

Clinical Patterns Based on Embolus Location

Distal/Peripheral PE

• Predominantly pleuritic chest pain
• May have pleural irritation and consolidation on chest X-ray
• Often referred to as "pulmonary infarction syndrome"
• Hemodynamic consequences are usually less severe 1

Central PE

• Predominantly features isolated dyspnea of rapid onset
• May have substernal angina-like chest pain
• More significant hemodynamic consequences
• Can progress to syncope or shock in severe cases 1

Diagnostic Findings

Blood Gas Analysis

• Hypoxemia is common but not universal
• Up to 20% of patients have normal arterial oxygen pressure
• 15-20% have normal alveolar-arterial oxygen gradient 1
• Hypocapnia is often present 1

Chest X-ray

• Usually abnormal but findings are non-specific 1
• Common findings:
  • Atelectasis or infiltrate (49%)
  • Pleural effusion (46%)
  • Pleural-based opacity/infarction (23%)
  • Elevated diaphragm (36%)
  • Decreased pulmonary vascularity (36%)
  • Amputation of hilar artery (36% in some series) 1

Electrocardiogram

• Right ventricular overload signs present in 50% of cases 1
• Specific findings:
  • S1Q3T3 pattern
  • T wave inversion in leads V1-V4
  • QR pattern in V1
  • Incomplete or complete right bundle branch block 1
  • These changes are typically seen in more severe forms of PE 1

Risk Stratification

PE severity can be classified based on estimated early mortality risk:

• High-risk PE: Characterized by hemodynamic instability (shock or persistent arterial hypotension) 1
• Non-high-risk PE: Further stratified by assessing right ventricular dysfunction and myocardial injury markers 1

Important Clinical Pitfalls

1. Individual symptoms and signs lack specificity: No single symptom or sign can reliably confirm or exclude PE 1

2. Normal oxygen saturation does not rule out PE: Up to 40% of patients have normal arterial oxygen saturation 1

3. PE in patients with pre-existing cardiopulmonary disease: May present only with worsening of baseline dyspnea 1

4. Missed diagnosis in emergency settings: Studies show that PE is frequently undiagnosed in emergency departments, leading to preventable deaths 2

5. Silent PE: Approximately 10% of cases are discovered incidentally during diagnostic workup for another disease 1

6. Risk factors assessment: The risk of PE increases with the number of risk factors present, but PE occurs frequently in individuals without any identifiable risk factors 1

The combination of clinical symptoms, signs, and awareness of risk factors should guide clinicians to consider PE in their differential diagnosis and proceed with appropriate diagnostic testing when indicated.