What are the key symptoms and signs to watch for in a patient suspected of having a pulmonary embolism, particularly those with a history of deep vein thrombosis, recent surgery, cancer, or other conditions that increase the risk of blood clots?

Key Clinical Presentations and Warning Signs of Pulmonary Embolism

Watch for sudden onset dyspnea, chest pain, syncope/fainting, or hemoptysis—at least one of these symptoms occurs in 94% of PE cases, and their presence should immediately trigger consideration of PE in your differential diagnosis. 1

Cardinal Symptoms to Monitor

Most Common Presentations:

• Sudden onset dyspnea (occurs in 78-81% of cases) is the single most frequent symptom and often presents as isolated breathlessness without cough, sputum, or chest pain 2, 1
• Chest pain (39-56% of cases), typically pleuritic in nature, often associated with the pulmonary hemorrhage syndrome 2, 1
• Syncope or fainting (22-26% of cases), particularly when accompanied by raised jugular venous pressure and hypotension, signals massive PE with hemodynamic compromise 2, 1
• Hemoptysis (5-7% of cases) as part of the pulmonary hemorrhage syndrome 2, 1

Critical Vital Sign Abnormalities:

• Tachypnea (respiratory rate >20/min) is present in most patients and should raise immediate suspicion 2
• Tachycardia is a common finding that warrants attention 3
• Hypoxemia or decreased oxygen saturation should prompt urgent evaluation 4

High-Risk Clinical Patterns Requiring Immediate Recognition

Three distinct presentations demand urgent action: 2

1. Sudden collapse with raised JVP (faintness and/or hypotension)—indicates massive PE with right ventricular strain
2. Pulmonary hemorrhage syndrome (pleuritic pain and/or hemoptysis)
3. Isolated dyspnea (breathlessness without cough, sputum, or chest pain)

Populations Where PE Is Easily Missed

Maintain heightened vigilance in: 2

• Elderly patients—symptoms may be atypical or attributed to other conditions
• Patients with severe pre-existing cardiorespiratory disease—PE symptoms overlap with baseline disease
• Patients presenting with isolated breathlessness only—this subtle presentation is frequently overlooked

Major Risk Factors That Should Trigger Suspicion

Strong provoking factors include: 5, 6

• Recent major surgery or trauma (especially lower limb fractures, hip/knee replacement)
• Recent immobilization or hospitalization
• Clinical deep vein thrombosis (look for unilateral leg swelling, pain, warmth)
• Previous proven DVT or PE
• Active cancer (particularly pancreatic, hematologic, lung, gastric, brain)
• Recent myocardial infarction (within 3 months)
• Hospitalization for heart failure or atrial fibrillation (within 3 months)

Important patient-related factors: 5

• Pregnancy or postpartum period
• Major medical illness requiring hospitalization
• Congestive heart failure or chronic cardiorespiratory disease
• Stroke or neurological disease causing lower limb immobility

Signs of Right Ventricular Dysfunction and Hemodynamic Instability

Monitor for indicators of severe PE: 3

• Elevated jugular venous pressure
• Hypotension or hemodynamic instability
• Reduced cardiac output
• Signs of impaired right ventricular contractility

Critical Pitfall to Avoid

PE is rare in patients under age 40 without risk factors, but do not dismiss the diagnosis if risk factors are present. 2 Only 1% of PE patients have no symptoms before diagnosis, so the absence of symptoms should not be used to exclude PE in high-risk patients 1.

When to Act Immediately

Start anticoagulation immediately (before imaging confirmation) in patients with intermediate or high clinical probability, as delaying anticoagulation while awaiting diagnostic confirmation significantly increases mortality 7. Use weight-based unfractionated heparin: 80 units/kg bolus, then 18 units/kg/hour infusion, targeting aPTT 1.5-2.5 times control 7.

Isolated symptoms of deep vein thrombosis (leg swelling/pain only) occur in only 3% of PE cases, so do not rely on DVT symptoms alone to trigger PE evaluation 1.