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Published on: 2/24/2026
Sudden chest pain with shortness of breath can signal a pulmonary embolism, a blood clot that often starts in the leg, travels to the lungs, blocks blood flow, and strains the heart; leg swelling or pain may come first. If suspected, seek emergency care now for tests like CT angiography and D-dimer and for prompt treatment with blood thinners, oxygen, or clot-busting therapy when indicated.
Risk is higher with immobility, recent surgery, cancer, estrogen use, pregnancy, smoking, obesity, heart disease, or prior clots; there are several factors to consider that can change diagnosis, treatment length, and prevention, so see the complete details below to guide your next steps.
Sudden chest pain can be frightening. While many causes are mild—such as muscle strain or acid reflux—some are serious and require urgent medical care. One of the most dangerous causes is a pulmonary embolism.
A pulmonary embolism (PE) occurs when a blood clot blocks an artery in the lungs. This can prevent oxygen from reaching parts of the lung and strain the heart. Without prompt treatment, a pulmonary embolism can become life-threatening. The good news: when recognized early, it is treatable.
This guide explains why pulmonary embolisms happen, the symptoms to watch for, and the vital medical steps you should take.
A pulmonary embolism happens when a clot—usually formed in the deep veins of the legs or pelvis—travels through the bloodstream to the lungs. This type of clot often starts as a condition called deep vein thrombosis (DVT).
When the clot lodges in a lung artery:
The severity of a pulmonary embolism depends on the size of the clot and how much of the lung is affected.
Pulmonary embolisms typically develop due to one or more of the following risk factors:
Most pulmonary embolisms begin as deep vein thrombosis. Clots form in deep leg veins when blood flow slows or the blood becomes more prone to clotting.
Long periods of sitting or lying down can increase risk. Examples include:
When the legs are still for too long, blood flow slows and clots may form.
Major surgery—especially orthopedic procedures like hip or knee replacement—raises pulmonary embolism risk. Trauma to the lower body also increases clot risk.
Certain cancers and chemotherapy treatments increase the body's tendency to form clots.
Estrogen increases clotting risk.
Conditions that may raise pulmonary embolism risk include:
Understanding your risk factors can help with prevention and early detection.
Symptoms of a pulmonary embolism can vary from mild to severe. Some people have subtle signs; others experience sudden, dramatic symptoms.
Because many pulmonary embolisms begin in the legs, you may notice:
If you experience sudden chest pain along with shortness of breath, seek emergency care immediately.
A pulmonary embolism is a medical emergency. Large clots can:
However, not all pulmonary embolisms are massive. Smaller clots may cause milder symptoms but still require prompt treatment to prevent complications or recurrence.
With modern treatment, many people recover fully—especially when care is sought quickly.
If you suspect a pulmonary embolism, time matters.
Call emergency services or go to the nearest emergency department if you have:
Do not attempt to "wait it out."
Doctors may perform:
These tests help confirm or rule out a pulmonary embolism.
Treatment typically includes:
Treatment duration varies. Some people need blood thinners for three months; others may require longer therapy depending on risk factors.
Prevention focuses on reducing clot risk, especially if you have known risk factors.
If you have a personal or family history of blood clots, speak to a doctor about prevention strategies.
Chest pain and shortness of breath can have many causes, including:
Because symptoms overlap, it can be difficult to know what's serious. If you're experiencing chest pain or breathing difficulties and want to better understand whether your symptoms could indicate a Pulmonary Embolism, a free online symptom checker can help you assess your risk level and determine if you need urgent care.
If symptoms are severe, sudden, or worsening, seek emergency treatment immediately.
Most people recover from a pulmonary embolism with appropriate treatment. However, possible complications include:
Follow-up care is essential. Your doctor may:
Adhering to treatment significantly reduces the risk of recurrence.
You should speak to a doctor promptly if you:
If symptoms suggest a possible pulmonary embolism, treat it as urgent. Early action can save your life.
Sudden chest pain should never be ignored. While many causes are minor, a pulmonary embolism is one condition that requires immediate attention.
Pulmonary embolisms occur when blood clots—often from the legs—travel to the lungs and block blood flow. Risk factors include immobility, surgery, cancer, hormonal therapy, and inherited clotting disorders. Symptoms often include chest pain and shortness of breath, and prompt medical evaluation is critical.
If you are uncertain about your symptoms, consider using a Pulmonary Embolism symptom checker to evaluate your risk and help guide your next steps. Most importantly, speak to a doctor immediately about any symptoms that could be serious or life-threatening.
When recognized and treated early, pulmonary embolism is manageable. Acting quickly makes all the difference.
(References)
* Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS). Eur Heart J. 2020 Jan 21;41(4):543-603. doi: 10.1093/eurheartj/ehz405. Epub 2019 Aug 31. PMID: 31504429.
* Chaparro L, Al-Samkari H, Connors JM. Risk factors for pulmonary embolism: A systematic review and meta-analysis. Thromb Res. 2021 Jan;197:179-192. doi: 10.1016/j.thromres.2020.10.038. Epub 2020 Oct 30. PMID: 33187843.
* Müller-Schall T, Mücke MM, Al-Samman B, et al. Diagnosis of Acute Pulmonary Embolism. Dtsch Arztebl Int. 2022 Nov 11;119(45):760-770. doi: 10.3238/arztebl.m2022.0298. PMID: 36629731; PMCID: PMC9931707.
* Agnelli G, Becattini C. Pulmonary embolism: an update on diagnosis and management. J Thromb Haemost. 2022 Aug;20(8):1733-1741. doi: 10.1111/jth.15802. Epub 2022 Jun 30. PMID: 35770511.
* Lombardi R, Scoccia E, Bellusci L, et al. The Pathophysiology of Pulmonary Embolism: A Clinical Review. J Clin Med. 2023 May 30;12(11):3799. doi: 10.3390/jcm12113799. PMID: 37298642; PMCID: PMC10254257.
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