Signs and Symptoms of Pulmonary Embolism
Suspect pulmonary embolism when patients present with unexplained dyspnea, pleuritic chest pain, or isolated breathlessness, particularly when accompanied by tachypnea (respiratory rate >20/min), as most PE patients are breathless and/or tachypneic. 1, 2
Three Classic Clinical Patterns
The British Thoracic Society identifies three distinct presentations that should raise immediate suspicion 1:
- Sudden collapse with raised jugular venous pressure (faintness and/or hypotension) - indicates massive PE with hemodynamic compromise 1
- Pulmonary hemorrhage syndrome (pleuritic pain and/or hemoptysis) - results from peripheral emboli causing pleural irritation 1, 2
- Isolated dyspnea (breathlessness without cough, sputum, or chest pain) - the most easily missed presentation 1
Primary Symptoms
Dyspnea (Most Common)
- Present in 80-85% of PE patients, making it the most frequent symptom 2, 3, 4
- Can be acute and severe in central PE, or mild and transient in small peripheral PE 2
- In patients with pre-existing heart failure or lung disease, worsening dyspnea may be the only clue to PE 2
- Unexplained dyspnea should always prompt consideration of PE 3, 4, 5
Chest Pain (Second Most Common)
- Pleuritic chest pain occurs in approximately 52% of PE patients - sharp, stabbing, or burning pain that intensifies with breathing 2, 6
- Substernal chest pain presents in approximately 12% of cases with angina-like quality, reflecting right ventricular ischemia 2
- Important caveat: 48% of PE patients have NO chest pain of any type 2
Tachypnea
- Respiratory rate >20/min occurs in 70% of PE patients 2
- Most patients are breathless and/or tachypneic 1
Other Symptoms
- Cough occurs in approximately 20% of cases 6
- Hemoptysis may be present, particularly with peripheral emboli causing pulmonary hemorrhage 1, 2
Critical Diagnostic Triad
The combination of dyspnea, tachypnea, or pleuritic pain is present in 97% of PE patients - only 3% lack all three features 2. This makes the absence of all three symptoms highly reassuring against PE.
High-Risk Populations Where PE Is Easily Missed
PE is frequently overlooked in 1:
- Elderly patients - may present atypically 1
- Patients with severe cardiorespiratory disease - symptoms attributed to underlying condition 1
- Patients with isolated dyspnea - no accompanying chest pain or hemoptysis 1
Major Risk Factors to Assess
When PE is suspected, the British Thoracic Society recommends scoring for these major risk factors 1:
- Recent immobilization or major surgery 1, 7
- Recent lower limb trauma and/or surgery 1, 7
- Clinical deep vein thrombosis 1
- Previous proven DVT or PE 1, 7
- Pregnancy or postpartum period 1, 7
- Major medical illness 1
- Malignancy 7
Note: PE is rare if age <40 with no risk factors, and estrogens are only a minor risk factor 1
Common Pitfalls to Avoid
- Do not rule out PE based on absence of chest pain - nearly half of patients have no pain 2
- Do not exclude PE based on normal oxygen saturation - up to 20% of PE patients have normal arterial oxygen pressure 2
- Individual symptoms lack specificity - predictive value of any single feature is less than 80% 2
- Many PE cases are asymptomatic - autopsy studies show most fatal PEs are unrecognized, and screening studies in high-risk populations reveal asymptomatic cases 8
- Do not dismiss symptoms in patients with pre-existing cardiopulmonary disease - worsening dyspnea may be the only manifestation 2
Clinical Reasoning Algorithm
- Assess for unexplained dyspnea, pleuritic chest pain, or isolated breathlessness 1, 3
- Check respiratory rate - tachypnea >20/min supports diagnosis 1, 2
- Identify which clinical pattern - collapse with hypotension, pulmonary hemorrhage syndrome, or isolated dyspnea 1
- Score major risk factors - each present risk factor increases probability 1, 7
- Consider alternative diagnoses - but maintain high suspicion if other diagnoses are unlikely 1
- Remember that absence of symptoms does not exclude PE - particularly in high-risk populations 8