Signs and Symptoms of Pulmonary Embolism
Dyspnea, chest pain, syncope, or hemoptysis—occurring singly or in combination—are present in over 90% of patients with pulmonary embolism, and at least one of these four cardinal symptoms occurs in 94% of cases. 1, 2
Cardinal Symptoms (In Order of Frequency)
Dyspnea (Most Common)
- Sudden onset dyspnea is the most frequent presenting symptom, occurring in 78-81% of patients 2
- Present in over 90% of cases when combined with tachypnea 1
- In central PE: dyspnea is acute, severe, and of rapid onset 1, 3
- In small peripheral PE: dyspnea is often mild and may be transient 1, 3
- In patients with pre-existing heart failure or pulmonary disease, worsening dyspnea may be the only symptom 1, 3
Chest Pain (Second Most Common)
Pleuritic chest pain (52% of cases):
- Sharp, stabbing, or burning quality that intensifies with respiration 3
- Caused by pleural irritation from distal emboli causing alveolar hemorrhage 1, 3
- Worsened by deep breathing, coughing, or respiratory movements 3
- Associated with peripheral emboli 3
Substernal angina-like pain (12% of cases):
- Retrosternal chest pain with anginal characteristics 3
- Likely reflects right ventricular ischemia from acute RV strain 1, 3
- Associated with central PE 3
Syncope or Pre-syncope (Third Most Common)
- Occurs in 22-26% of patients 2
- Indicates severely reduced hemodynamic reserve 1
- Associated with higher prevalence of hemodynamic instability and RV dysfunction 1
- May be the presenting symptom in 17% of patients presenting with syncope 1
Hemoptysis (Least Common Cardinal Symptom)
Physical Examination Findings
Respiratory Signs
- Tachypnea (respiratory rate >20/min) occurs in 70% of patients 3
- The combination of dyspnea, tachypnea, or pleuritic pain is present in 97% of PE patients 3
Cardiovascular Signs
- Tachycardia (sinus tachycardia in 40% of patients) 1
- Shock or hypotension in high-risk PE (indicates >15% early mortality risk) 1
- Atrial arrhythmias, most frequently atrial fibrillation, may be associated with acute PE 1
ECG Findings (More Common in Severe Cases)
- Inversion of T waves in leads V1-V4 1
- S1Q3T3 pattern 1
- QR pattern in V1 1
- Incomplete or complete right bundle branch block 1
- In milder cases, sinus tachycardia may be the only abnormality 1
Critical Clinical Pitfalls
Normal Findings Do NOT Exclude PE
- Up to 20-40% of patients have normal arterial oxygen saturation (SaO2) 1, 3
- 20% have a normal alveolar-arterial oxygen gradient 1
- Nearly 48% of PE patients do not have chest pain of any type 3
- Only 3% of patients lack all three features of dyspnea, tachypnea, or pleuritic pain 3
Asymptomatic and Unrecognized Cases
- Many cases of PE are asymptomatic or discovered incidentally 1, 4
- Autopsy studies show most fatal PE cases are unrecognized and undiagnosed 4
- Only 1% of patients had no symptoms before PE diagnosis in one large series 2
Non-Specific Presentations
- Individual clinical signs and symptoms are neither sensitive nor specific 1
- The predictive value of any single feature is less than 80% 3
- Chest X-ray is usually abnormal but findings (atelectasis, pleural effusion, elevated hemidiaphragm) are non-specific 1
Risk Stratification Based on Presentation
High-Risk PE (>15% Early Mortality)
- Presence of shock or hypotension 1
- Indicates central or extensive PE with severely reduced hemodynamic reserve 1, 3
- Requires immediate thrombolysis or embolectomy 1
Intermediate-Risk PE (3-15% Mortality)
- At least one marker of RV dysfunction or myocardial injury present 1
- May have syncope, RV strain on ECG, or elevated biomarkers 1
Low-Risk PE (<1% Mortality)
- All checked RV dysfunction and myocardial injury markers negative 1
- Typically presents with isolated mild symptoms 1
Predisposing Factors
Knowledge of VTE risk factors is essential, as PE probability increases with the number of factors present 1
- However, in 30-40% of cases, PE occurs without any predisposing factors (unprovoked PE) 1