Pulmonary embolism

Pulmonary embolism (PE) is a blockage of an artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream. This can cause symptoms such as shortness of breath, chest pain when breathing in, and sometimes coughing up blood. People may also notice signs like low blood oxygen levels, rapid breathing, and a rapid heart rate.

Most often, PE happens when a blood clot from the leg travels to the lungs. Factors that increase the risk include advanced age, cancer, long periods of bed rest, smoking, long travel, certain genetic conditions, pregnancy, and after some surgeries. Doctors diagnose PE using tests like a D-dimer blood test, CT pulmonary angiography, or ultrasound of the legs.

Preventing PE can involve moving around after surgery, doing exercises while sitting, and sometimes using blood thinners. Treatment usually includes medications such as heparin or warfarin to stop more clots from forming. In severe cases, special medications or surgery may be needed. Pulmonary embolism affects many people each year, and it becomes more common as people get older.

Signs and symptoms

A pulmonary embolism can cause sudden symptoms like shortness of breath, chest pain that hurts more when you breathe in, and coughing up blood. In more serious cases, a person might turn blue around the lips and fingers, feel very weak, or have trouble with their blood flow.

Doctors might hear certain sounds when listening to the lungs or heart, and they may notice a slight fever if there is bleeding in the lungs. Smaller blood clots in the lungs might cause pain but not other symptoms, while larger clots can cause low blood pressure, a fast heart rate, and fainting.

Risk factors

Most blood clots that cause pulmonary embolism come from deep vein thrombosis, especially in the upper part of the leg. These clots can break free and travel to the lungs. Conditions that increase the risk of these clots include recent hip or knee surgery, certain cancers like pancreatic or colon cancer, pregnancy, and taking estrogen-containing medications.

Other risk factors include things like prolonged immobility (such as long flights), injury, obesity, and genetic conditions that affect blood clotting. Having varicose veins, high blood pressure in the lungs, diabetes, or breaking a hip and being unable to move can also increase the risk of a pulmonary embolism.

Diagnosis

To diagnose a pulmonary embolism, doctors look at certain signs and symptoms. If a person has low risk — like being under 50, having a heart rate under 100 beats per minute, oxygen levels above 94%, and no leg swelling, coughing up blood, recent surgery, or history of blood clots — they might not need more tests.

For those at higher risk, tests are needed. A CT pulmonary angiogram (CTPA) is the best way to diagnose a pulmonary embolism because it is easy and accurate. Other tests, like a compression ultrasound of the legs, can also help confirm the diagnosis. These tests check for blood clots in the legs, which can sometimes travel to the lungs.

The decision to do imaging tests depends on the person's medical history, symptoms, and physical examination. Doctors use special rules, like the Wells score, to help decide if a pulmonary embolism is likely. These rules look at things like heart rate, recent surgery, and symptoms to estimate the chance of a pulmonary embolism.

Blood tests, like checking the level of D-dimer, can also help. A normal D-dimer level usually means there is no pulmonary embolism. Imaging tests such as CT pulmonary angiography are used to see the arteries in the lungs clearly. Another option is a ventilation/perfusion scan, which is useful for people who cannot have CT scans. Overall, diagnosing a pulmonary embolism involves careful evaluation of symptoms, risk factors, and specific tests to ensure an accurate diagnosis.

Prevention

Further information: Thrombosis prevention

Pulmonary embolism can often be prevented in people who have certain risk factors. For example, those staying in the hospital might be given special medicines such as low molecular weight heparin or fondaparinux, along with special stockings, to help stop blood clots from forming in the legs. These clots can sometimes travel to the lungs and cause a pulmonary embolism. After treatment to dissolve blood clots, taking aspirin regularly can help prevent another pulmonary embolism from happening.

Treatment

Anticoagulant therapy is the main way to treat pulmonary embolism. At first, people may need extra support like oxygen or pain relief, and they often stay in the hospital until their condition is stable. For many years, doctors used medicines called vitamin K antagonists, but now there are newer options that do not need careful monitoring.

There are different medicines to stop blood clots, including some that can be taken at home. For people with cancer or during pregnancy, special treatments are used to keep them safe. Sometimes, if the blockage is very severe, doctors may use a special procedure to break up the clot directly. Surgery is rarely needed, but it can help in certain cases.

Prognosis

Pulmonary embolism (PE) can be serious, but many people recover well with treatment. The outcome depends on how much of the lung is affected and whether the person has other health problems. Blood flow usually starts to improve within the first couple of days after treatment.

Doctors use special tools to help predict how serious a PE might be and how likely a person is to recover. These tools look at things like the person's symptoms and health history to decide which treatments are best.

Epidemiology

Every year, around 10 million people experience pulmonary embolisms worldwide. In the United States, these events are a leading cause of death, contributing to many fatalities annually. The number of hospital admissions for pulmonary embolisms has increased from 1993 to 2012, but thanks to advances in medicine, deaths from this condition have decreased during the same period.

Older individuals, especially those over 70, are at a higher risk for conditions like venous thromboembolism, which can make pulmonary embolisms more severe. This increased risk is often linked to less physical activity and other health factors common in older age groups.