How to Detect Pulmonary Embolism: Symptoms, Testing, and Diagnostic Procedures

Recognizing the signs of a pulmonary embolism (PE) is crucial for timely medical intervention. This potentially life-threatening condition occurs when a blood clot—often originating in the deep veins of the legs—travels to the lungs and blocks one or more arteries. Early detection can significantly improve outcomes and reduce complications.

Common Symptoms of Pulmonary Embolism

Sudden and unexplained shortness of breath is one of the hallmark symptoms of PE. This may be accompanied by sharp chest pain that worsens with deep breathing, coughing, or physical activity. In some cases, patients may cough up blood-tinged sputum, a sign that requires immediate medical attention.

Additional warning signs include rapid heart rate, lightheadedness, excessive sweating, and feelings of anxiety or impending doom. If you experience persistent low oxygen levels that don't respond to supplemental oxygen, especially without a clear cause, pulmonary embolism should be strongly suspected.

Initial Blood and Cardiac Tests

When PE is suspected, healthcare providers typically begin with a series of initial tests to assess overall health and rule out other conditions. A complete blood count (CBC) helps evaluate for infection or anemia, while cardiac biomarkers like troponin can indicate heart strain caused by the clot.

D-dimer testing is particularly useful in ruling out PE in low-risk patients. Elevated D-dimer levels suggest recent clot formation, although they are not specific to PE and can be elevated in other conditions such as infection or recent surgery.

Imaging Techniques for Confirming Diagnosis

To confirm the presence of a pulmonary embolism, advanced imaging studies are essential. The most commonly used and reliable method is CT pulmonary angiography (CTPA). This non-invasive scan provides detailed images of the pulmonary arteries and can clearly identify blockages caused by blood clots.

For patients who cannot undergo CT due to contrast allergies or kidney issues, alternative options include ventilation/perfusion (V/Q) scintigraphy. This nuclear medicine test compares airflow and blood flow in the lungs, highlighting areas where perfusion is reduced despite normal ventilation—a classic sign of PE.

Other Diagnostic Tools

In select cases, magnetic resonance imaging (MRI) or MR pulmonary angiography may be used, especially during pregnancy or when radiation exposure must be avoided. While less commonly performed, these methods offer valuable insights without ionizing radiation.

The gold standard, though rarely used today due to its invasiveness, is conventional pulmonary angiography. It involves inserting a catheter into the pulmonary artery and injecting contrast dye under X-ray guidance. A positive result from any one of these four imaging modalities—CTPA, V/Q scan, MRI, or pulmonary angiography—is sufficient to confirm the diagnosis.

Act Fast: Time Is Critical

Because pulmonary embolism can rapidly progress to shock or cardiac arrest, prompt evaluation and treatment are vital. If you or someone else exhibits symptoms suggestive of PE, seek emergency medical care immediately. Early diagnosis through appropriate testing can save lives and prevent long-term damage to the heart and lungs.