Pulmonary Embolism Symptoms: Warning Signs of a Blood Clot in the Lung

What is a pulmonary embolism?

A pulmonary embolism occurs when a blood clot — most often one that formed in the deep veins of the legs (called deep vein thrombosis, or DVT) — breaks free, travels through the bloodstream, and lodges in one of the arteries supplying blood to the lungs. The blocked artery prevents a portion of the lung from receiving blood to exchange for oxygen, putting stress on the right side of the heart and reducing oxygen delivery throughout the body 1Ref 1National Heart, Lung, and Blood Institute (2023).Venous Thromboembolism — Pulmonary Embolism (PE).Pulmonary embolism overview: symptoms (sudden shortness of breath, chest pain), diagnostic approach (CT pulmonary angiography, D-dimer, V/Q scan), and link to DVT.

Small clots may cause minimal symptoms or none at all. Large or multiple clots can cause severe symptoms and can be rapidly fatal — sudden death is the first symptom in approximately one quarter of people who have a PE 2Ref 2Centers for Disease Control and Prevention (2024).Data and Statistics on Venous Thromboembolism (Blood Clots).Up to 100,000 Americans die of VTE (including PE) each year; sudden death is the first symptom in about 25% of PE cases; risk factors including surgery, immobility, cancer, pregnancy. This is why any combination of the classic symptoms should be evaluated urgently, not monitored at home.

What are the symptoms of pulmonary embolism?

Symptoms vary widely depending on the size and location of the clot. Classic presentations include 1Ref 1National Heart, Lung, and Blood Institute (2023).Venous Thromboembolism — Pulmonary Embolism (PE).Pulmonary embolism overview: symptoms (sudden shortness of breath, chest pain), diagnostic approach (CT pulmonary angiography, D-dimer, V/Q scan), and link to DVT:

Sudden shortness of breath — the most common symptom. May come on out of nowhere, at rest or with exertion. The feeling that you cannot get enough air.

Pleuritic chest pain — a sharp, stabbing pain in the chest that typically worsens when you take a deep breath, cough, or move. This is different from the pressure or squeezing of a heart attack.

Rapid or pounding heart rate — the heart speeds up to compensate for reduced oxygen delivery.

Coughing — sometimes productive of small amounts of blood-tinged or rust-colored mucus (hemoptysis).

Feeling faint, lightheaded, or actually passing out — in larger PEs, blood pressure drops and blood flow to the brain is reduced.

Anxiety or a sense of dread — many patients describe an unexplained feeling that something is seriously wrong.

Symptoms of DVT in a leg — one calf or thigh that is swollen, red, warm, or tender. This may come first, alongside the lung symptoms, or not at all.

Importantly, PE can present with just one or two of these symptoms, or in atypical ways — especially in older adults. Any sudden, unexplained combination of chest discomfort and breathlessness deserves urgent evaluation.

Who is at higher risk for pulmonary embolism?

PE is more likely in people with certain risk factors 2Ref 2Centers for Disease Control and Prevention (2024).Data and Statistics on Venous Thromboembolism (Blood Clots).Up to 100,000 Americans die of VTE (including PE) each year; sudden death is the first symptom in about 25% of PE cases; risk factors including surgery, immobility, cancer, pregnancy. Common ones include:

• Recent surgery, especially orthopedic surgery (hip or knee replacement)
• Prolonged immobility — long flights, bed rest, hospitalization
• Cancer, particularly certain types that increase clotting tendency
• Prior history of DVT or PE
• Pregnancy or recent childbirth
• Use of estrogen-containing medications (birth control pills, hormone therapy)
• Smoking
• Obesity
• Heart failure or chronic lung disease
• Inherited clotting disorders

Having one or more risk factors alongside classic symptoms increases the urgency of evaluation. But PE can occur without any obvious risk factor — which is one reason it is frequently missed initially.

How is pulmonary embolism diagnosed?

A PE cannot be diagnosed or ruled out based on symptoms alone. Emergency or inpatient evaluation typically includes 1Ref 1National Heart, Lung, and Blood Institute (2023).Venous Thromboembolism — Pulmonary Embolism (PE).Pulmonary embolism overview: symptoms (sudden shortness of breath, chest pain), diagnostic approach (CT pulmonary angiography, D-dimer, V/Q scan), and link to DVT3Ref 3National Heart, Lung, and Blood Institute (2023).Venous Thromboembolism — Diagnosis.Diagnostic workup for PE including CT pulmonary angiography as the main test, D-dimer blood test, and V/Q scan as alternatives:

• Blood test (D-dimer): A marker of clot activity. A normal D-dimer in a low-risk person essentially rules out PE. However, D-dimer is elevated in many conditions, so a high result is not by itself a diagnosis.
• CT pulmonary angiography (CTPA): The gold standard imaging test, which directly visualizes clots in the pulmonary arteries. This is the most common definitive test.
• Ultrasound of the legs: Can detect DVT, which supports the diagnosis if found alongside symptoms.
• Ventilation-perfusion (V/Q) scan: Used when CT is contraindicated (e.g., contrast allergy, kidney disease).
• ECG: Often shows characteristic changes with PE, though it is not diagnostic on its own.

Because PE is potentially fatal and treatable, emergency departments take these symptoms seriously.

What kind of specialist treats pulmonary embolism?

PE is treated by emergency physicians initially, and then typically managed by a team that may include:

• Pulmonologists (lung specialists) — often lead outpatient follow-up and decisions about anticoagulation duration
• Hematologists — when an underlying clotting disorder is suspected
• Cardiologists — for large PEs affecting heart function
• Vascular surgeons or interventional radiologists — in rare cases requiring clot removal

This is not a condition Gale manages directly as a primary-care service. If you have already been diagnosed and treated and are looking for follow-up coordination, Gale can help you navigate referrals and prepare for specialist appointments. For symptoms you think could be a PE right now, go to the emergency room — do not wait for a telehealth visit.