What are the signs of pulmonary embolism?

Signs of Pulmonary Embolism

Dyspnea (shortness of breath) is the most common symptom of pulmonary embolism, present in approximately 80% of patients with PE, and can be acute and severe in central PE or mild and transient in small peripheral PE. 1, 2

Common Clinical Presentations

Symptoms

• Dyspnea (shortness of breath) - present in 80% of cases, can be acute and severe or mild and transient 1, 2
• Pleuritic chest pain - present in 52% of cases, typically caused by pleural irritation due to distal emboli 1, 2
• Substernal chest pain - present in 12% of cases, may represent right ventricular ischemia 1
• Syncope - present in 19% of cases, may occur even without hemodynamic instability 1, 3
• Hemoptysis - present in 11% of cases, results from alveolar hemorrhage caused by small distal emboli 1, 2
• Cough - present in 20% 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
• Signs of deep vein thrombosis - present in 15% of cases 1
• Fever (>38.5°C) - present in 7% of cases 1
• Cyanosis - present in 11% of cases 1
• Hypotension and shock - hallmark of central PE with severe hemodynamic consequences 1

Presentation Based on PE Location

Central PE

• Acute and severe dyspnea 1, 2
• Substernal chest pain with anginal characteristics 1, 2
• Higher probability of hemodynamic instability 1, 2
• More frequent syncope 1, 2

Peripheral PE

• Mild and sometimes transient dyspnea 1, 2
• Pleuritic chest pain 1, 2
• Hemoptysis 1, 2
• Pleural effusion (usually mild) 1, 2

Diagnostic Findings

Chest X-ray Findings

• Atelectasis or infiltrate - present in 49% of cases 1
• Pleural effusion - present in 46% of cases 1
• Pleural-based opacity (infarction) - present in 23% of cases 1
• Elevated diaphragm - present in 36% of cases 1
• Decreased pulmonary vascularity - present in 36% of cases 1
• Amputation of hilar artery - present in 36% of cases 1

Laboratory Findings

• Hypoxemia - present in 75% of cases, although up to 20% of patients may have normal arterial oxygen pressure 1, 2
• Hypocapnia - often present 2

Electrocardiographic Findings

• Right ventricular overload - present in 50% of cases 1
• S1Q3T3 pattern (S wave in lead I, Q wave and inverted T wave in lead III) 1, 2
• Inversion of T waves in leads V1-V4 1, 2
• QR pattern in V1 1, 2
• Right bundle branch block (complete or incomplete) 1, 2

Special Considerations

• In patients with pre-existing heart failure or pulmonary disease, worsening dyspnea may be the only symptom indicative of PE 1, 2
• PE can be completely asymptomatic and discovered incidentally during diagnostic studies for other conditions 2
• Approximately 40% of patients with PE do not have predisposing factors 2
• At least one of the four main symptoms (dyspnea, chest pain, syncope, hemoptysis) is reported in 94% of patients with PE 4
• Only 1% of patients have no symptoms before PE is diagnosed 4

Risk Stratification

• High-risk PE is defined by hemodynamic instability (persistent arterial hypotension and/or shock), indicating high risk of early mortality 2
• Non-high-risk PE requires additional evaluation to determine level of risk and guide management decisions 2

Clinical Pitfalls to Avoid

• Do not rule out PE based on normal oxygen saturation, as up to 40% of patients may have normal arterial oxygen saturation 2
• Do not dismiss transient symptoms, as they can lead to delayed diagnosis or misdiagnosis 3
• Do not overlook PE in patients with pre-existing cardiopulmonary disease where worsening dyspnea may be the only new symptom 1, 2
• Do not rely solely on individual clinical signs or symptoms, as they lack specificity 1
• Consider PE in any patient presenting with sudden onset dyspnea, chest pain, syncope, or hemoptysis that cannot be explained by other causes 4