In short
Pulmonary embolism is a serious medical emergency that requires quick diagnosis and immediate treatment. Recognizing the warning signs and knowing which tests can identify this life-threatening condition may make the difference between recovery and severe complications.
Key points
- Seek emergency care immediately if you experience sudden shortness of breath or chest pain – about one-third of pulmonary embolism patients die before diagnosis, making quick action crucial.
- CT pulmonary angiography is the gold standard diagnostic test that creates detailed images showing whether blood clots are blocking your lung arteries.
- A D-dimer blood test can help rule out pulmonary embolism when levels are low, potentially saving you from unnecessary imaging tests.
- Doctors use clinical scoring systems like Wells criteria to assess how likely you are to have pulmonary embolism before ordering expensive or invasive tests.
- Leg ultrasound often accompanies pulmonary embolism diagnosis because most lung clots originate as deep vein thrombosis in your legs.
- Regular chest X-rays cannot detect pulmonary embolism but help doctors exclude other conditions with similar symptoms like pneumonia or collapsed lung.
- With prompt diagnosis and treatment, pulmonary embolism is rarely fatal, but delayed care can lead to permanent lung damage or heart failure.
- Once you've had one pulmonary embolism, your future risk depends on the cause – temporary situations like surgery carry lower recurrence risk than ongoing conditions like cancer.
Introduction: Who Should Undergo Diagnostics
If you suddenly experience shortness of breath, chest pain that worsens with deep breathing, or feel lightheaded or faint, you need medical attention right away. These symptoms could signal a pulmonary embolism, which is a blood clot that blocks an artery in your lungs. This condition is a medical emergency that demands immediate diagnosis and treatment.
Pulmonary embolism can be difficult to identify because its symptoms often resemble those of other heart or lung conditions. Some people may experience sudden, severe symptoms within seconds or minutes, while others notice milder signs that develop gradually over days or even weeks. Because about 33% of people with pulmonary embolism die before receiving a diagnosis and treatment, seeking medical care at the first sign of trouble is critical.
You should seek diagnostic testing immediately if you have any combination of the following symptoms: sudden breathlessness (whether you've been active or at rest), sharp chest pain that gets worse when you cough or take a deep breath, rapid breathing, fast heartbeat, coughing up blood, pale or bluish skin, excessive sweating, or feelings of anxiety with lightheadedness.
Certain people are at higher risk and should be especially alert to symptoms. If you've had surgery recently, especially joint replacement, if you've been on bed rest for an extended period, if you have cancer, heart disease, or a broken bone, or if you take hormone-based medications like birth control pills, you face increased risk. Pregnant women and those who have recently given birth also need to be vigilant, as the risk is highest for about six weeks after childbirth. Long periods without movement, such as during lengthy flights or car trips, can also increase your risk.
Diagnostic Methods
Diagnosing pulmonary embolism can be challenging because the condition shares symptoms with many other heart and lung problems. This is why doctors use a combination of medical history, physical examination, and several different tests to confirm whether you have this condition.
Initial Assessment and Clinical Scoring
When you arrive at the hospital with symptoms that might suggest pulmonary embolism, doctors first assess how likely it is that you actually have this condition. They use standardized tools called clinical scoring systems such as the Wells criteria and Geneva score. These systems consider your symptoms, risk factors, and physical examination findings to calculate the probability that you have a pulmonary embolism. This probability assessment helps determine which diagnostic tests you need next.
Your doctor will ask about your medical history, including whether you've had blood clots before, recent surgeries, long periods of immobility, cancer, or other conditions that increase clotting risk. They'll also perform a physical examination, checking your breathing, heart rate, blood pressure, and looking for signs like swelling, redness, warmth, or pain in your legs, which could indicate deep vein thrombosis (a blood clot in your leg that can travel to your lungs).
Blood Tests
If your risk level appears low to moderate based on the initial assessment, your doctor will likely order a blood test called a D-dimer test. D-dimer is a substance that your body produces when it breaks down blood clots. If this test shows low levels of D-dimer, it can rule out pulmonary embolism, meaning you probably don't have this condition and won't need further testing. However, high D-dimer levels don't necessarily confirm pulmonary embolism because many other conditions can also raise these levels.
Your healthcare team may also check your blood oxygen and carbon dioxide levels through an arterial blood gas test. A clot in your lung can lower the oxygen in your blood. Additionally, doctors sometimes measure levels of substances called troponin and brain natriuretic peptide, which can indicate whether your heart is under strain from the pulmonary embolism.
Imaging Tests
CT pulmonary angiography (CTPA) is the main test used to diagnose pulmonary embolism. This imaging test takes detailed pictures of the blood vessels in your lungs and can clearly show whether blood clots are blocking any of these vessels. During this procedure, you lie on a table that moves through a CT scanner while X-rays are taken from different angles. A special dye is usually injected into your vein to make the blood vessels show up more clearly on the images. This test is highly accurate and is the standard way to confirm pulmonary embolism.
If CT scanning isn't available or suitable for you, doctors may use a ventilation-perfusion scan (also called a V-Q scan). This test involves two parts: one measures air flow in your lungs (ventilation) and the other measures blood flow (perfusion). The test uses small amounts of radioactive material to create images. If areas of your lung have good air flow but poor blood flow, this suggests a pulmonary embolism might be blocking blood vessels in those areas.
Ultrasound of your legs, specifically duplex ultrasonography or compression ultrasonography, uses sound waves to check for blood clots in the deep veins of your legs. A wand-shaped device called a transducer is moved over your skin, creating moving images of your veins. If doctors find clots in your legs, they know these could travel to your lungs and cause pulmonary embolism. This test is noninvasive and painless. Finding clots in your legs doesn't confirm pulmonary embolism, but their absence makes it less likely.
Other Diagnostic Tests
A chest X-ray cannot diagnose pulmonary embolism and may even appear normal when you have this condition. However, doctors often order this test to rule out other conditions with similar symptoms, such as pneumonia or a collapsed lung.
An electrocardiogram (EKG or ECG) measures the electrical activity of your heart. While it cannot directly show pulmonary embolism, it can reveal patterns suggesting that your heart is under strain, which happens when large clots block blood flow to your lungs. This test can also help doctors rule out a heart attack, which can cause similar symptoms.
In some cases, doctors may perform an echocardiogram, which is an ultrasound of your heart. This test can show whether the right side of your heart is working harder than normal or showing signs of strain, which can occur with pulmonary embolism. This test is particularly useful for patients who are too unstable to be moved to a CT scanner.
In rare situations where other tests are inconclusive and pulmonary embolism is strongly suspected, doctors may perform pulmonary angiography. This involves threading a thin, flexible tube (catheter) through your blood vessels to your lungs while injecting dye and taking X-ray images. This test is very accurate but is invasive and carries more risks than other imaging methods, so it's rarely used now that CT technology has improved.
Diagnostics for Clinical Trial Qualification
Clinical trials studying new treatments for pulmonary embolism use standardized diagnostic criteria to ensure all enrolled patients truly have this condition. These trials typically require confirmation through CT pulmonary angiography, as this is considered the gold standard for diagnosis.
Many clinical trials use risk stratification systems to categorize patients based on the severity of their pulmonary embolism. These systems combine clinical scoring tools like the Wells criteria or Geneva score with imaging findings and blood test results. Researchers use biomarkers (measurable substances in your blood) such as troponin and brain natriuretic peptide levels to assess how much strain the pulmonary embolism is placing on your heart. This information helps determine whether patients qualify for specific treatment trials.
Clinical trials often include ultrasound examination of leg veins to document whether deep vein thrombosis is present alongside pulmonary embolism. This information helps researchers understand the complete picture of venous thromboembolism (the medical term that includes both deep vein thrombosis and pulmonary embolism). Some trials also require echocardiography to measure heart function and detect right ventricular strain, which indicates more severe cases.
Trials may exclude patients whose pulmonary embolism is too mild or too severe. For example, studies testing blood-thinning medications might only include patients with confirmed clots but without severe low blood pressure or shock. Conversely, trials testing aggressive treatments like clot-dissolving drugs might specifically enroll patients with massive pulmonary embolism who have unstable vital signs.
Prognosis and Survival Rate
Prognosis
The outlook for people with pulmonary embolism depends greatly on how quickly they receive diagnosis and treatment. With timely medical care, pulmonary embolism is seldom fatal, and most people recover well. However, the condition can cause permanent damage to your lungs, put strain on your heart leading to heart failure, and can be life-threatening depending on the size and number of clots.
Several factors influence your prognosis. The size and location of the blood clot matter significantly – larger clots that block major blood vessels are more dangerous than smaller ones in minor vessels. Whether you have underlying heart or lung disease also affects your outcome, as these conditions make it harder for your body to cope with reduced oxygen levels. Quick treatment with blood thinners greatly reduces your risk of serious complications.
After recovering from an initial pulmonary embolism, you face an increased risk of having another blood clot in the future. However, this risk varies depending on what caused your first clot. If your pulmonary embolism resulted from a temporary situation like recent surgery or prolonged bed rest, your future risk is relatively low once you recover. But if you have ongoing risk factors like cancer, genetic clotting disorders, or unknown causes, your risk of recurrence is higher, sometimes requiring lifelong blood-thinning medication.
For patients whose pulmonary embolism had no clear temporary cause, the risk of having another blood clot within the next year is about 10 to 15 percent after completing three to six months of blood thinner treatment. Within five years, the risk of recurrence is approximately 5 percent.
Survival Rate
Pulmonary embolism is a serious condition with significant mortality. About 33% of people with pulmonary embolism die before they receive a diagnosis and treatment, highlighting why immediate medical attention is so critical when symptoms appear.
However, when pulmonary embolism is diagnosed and treated promptly, survival rates improve dramatically. Quick treatment with blood-thinning medications greatly reduces the chance of death. The specific survival rate depends on the severity of the pulmonary embolism and whether it causes unstable vital signs. Patients who develop very low blood pressure or shock from massive clots face the highest risk, while those with smaller clots and stable vital signs generally have much better outcomes with appropriate treatment.
In the United States, pulmonary embolism affects about 900,000 people annually and causes more than 10,000 to 12,000 deaths per year. In Europe, it's estimated to cause more than 30,000 to 40,000 deaths annually. Despite these concerning numbers, it's important to remember that with today's diagnostic tools and treatments, many people survive pulmonary embolism and return to normal activities, especially when they receive care quickly.
