Chest pain, respiratory distress, and any sudden unexplained lowering of blood pressure suggest pulmonary embolism (Table 1). Most people first come to the physician because of shortness of breath or chest pain. The typical patient has low blood pressure, distended neck veins, and syncope (fainting). Massive pulmonary embolism causes acute cor pulmonale (overload of the heart’s right ventricle), with sudden collapse of the cardiovascular system, syncope, or sudden death.

Table 1. Symptoms and Signs of Pulmonary Embolism in Selected Patients With Pulmonary Embolism

An embolus that obstructs an end artery (artery that branches out without connecting to other arteries) can lead to pulmonary infarction (obstruction and death of lung tissue). When the infarct has been present long enough to cause pleural inflammation, chest pain worsens when the person breathes. The person may also have rales, a cough, and possible hemoptysis (blood in sputum).

In people with severe cardiopulmonary disease (e.g., chronic obstructive pulmonary disease or congestive heart failure); even a small pulmonary embolism can cause symptoms and prove fatal.

Small pulmonary embolisms occur in up to 58% of surgical patients and usually cause no symptoms. Patients eventually recover even without treatment.