What are the signs and symptoms of pulmonary embolism?

Signs and Symptoms of Pulmonary Embolism

The clinical signs and symptoms of acute pulmonary embolism are nonspecific, but most patients present with at least one of four cardinal symptoms: sudden onset dyspnea (most common at 78-81%), chest pain (39-56%), syncope or presyncope (22-26%), or hemoptysis (5-7%). 1, 2

Cardinal Symptoms

• Sudden onset dyspnea is the most frequent presenting symptom, occurring in 78-81% of patients across different clinical settings 2
• Chest pain (often pleuritic) occurs in 39-56% of cases, with higher rates in younger patients and lower rates in older women with low-risk PE 3, 2
• Syncope or fainting presents in 22-26% of patients and is associated with higher prevalence of hemodynamic instability 1, 2
  • Syncope occurs more frequently in older men and women compared to younger patients in low-risk PE (15.5% vs 11.3% vs 4.5%; p=0.009) 3
• Hemoptysis is less common at 5-7% overall but is more prominent in younger men, particularly those with intermediate-risk and high-risk PE 3, 2

Critical Clinical Presentation: High-Risk PE

Hemodynamic instability defines high-risk PE and indicates severely reduced hemodynamic reserve requiring emergency intervention. 1

The ESC guidelines define hemodynamic instability as one of the following: 1

• Cardiac arrest requiring cardiopulmonary resuscitation
• Obstructive shock with end-organ hypoperfusion (altered mental status, cold/clammy skin, oliguria/anuria, increased serum lactate)
• Persistent hypotension: systolic BP <90 mmHg or systolic BP drop ≥40 mmHg lasting >15 minutes (not caused by new-onset arrhythmia, hypovolemia, or sepsis), or need for vasopressors

Physical Examination Findings

• Tachycardia increases in frequency with PE severity across all age and sex subgroups 3
• Tachypnea is a common finding that should prompt consideration of PE 4
• Signs of deep vein thrombosis (leg swelling, pain, erythema) occur in only about 3% as isolated symptoms 2
• Hypoxemia results from ventilation/perfusion mismatch, though arterial blood gas analysis contributes poorly to diagnosis 1, 5

Age and Sex-Specific Variations

• Younger men more frequently present with hemoptysis (11.7% in intermediate-risk, 13.8% in high-risk PE) and pneumonia (31.8% in low-risk PE) compared to other demographic groups 3
• Older women with low-risk PE present with chest pain less commonly (35.8%) than men and younger women (48.8-55.8%) 3
• Older patients more frequently have syncope with low-risk PE compared to younger patients 3

Important Clinical Considerations

At least one of the four cardinal symptoms (dyspnea, chest pain, syncope, hemoptysis) is present in 94% of PE patients, meaning only 1% of patients are completely asymptomatic at presentation. 2

• The incidence of dyspnea, syncope, and tachycardia increases with PE severity regardless of sex and age 3
• Right-to-left shunting through a patent foramen ovale occurs in approximately one-third of patients, potentially causing severe hypoxemia and increased risk of paradoxical embolization and stroke 1
• Pulmonary infarction syndrome (small distal emboli causing alveolar hemorrhage) presents with hemoptysis, pleuritis, and mild pleural effusion 1

Common Pitfalls

Because no individual symptom or sign can definitively diagnose or exclude PE, clinicians must use validated clinical prediction rules (Wells score, revised Geneva score) rather than relying on clinical presentation alone. 1, 4

• The nonspecific nature of PE symptoms means they are encountered in a wide range of pulmonary diseases, making clinical diagnosis difficult 1, 5
• Shortness of breath and smoking history have been significantly associated with negative angiography results, highlighting the low specificity of individual symptoms 6
• Routine laboratory investigations (arterial blood gases, LDH, complete blood count) contribute poorly to making the diagnosis 5