Pulmonary embolism is a blockage in one of the pulmonary arteries in your lungs. In
most cases, pulmonary embolism is caused by blood clots that travel to the lungs
the legs or, rarely, other parts of the body (deep vein thrombosis).
Because the clots block blood flow to the lungs, pulmonary embolism can be lifethreatening. However, prompt treatment greatly reduces the risk of death.
Pulmonary embolism symptoms can vary greatly. Common signs and symptoms include:
Other signs and symptoms that can occur with pulmonary embolism include:
Pulmonary embolism occurs when a clump of material, most often a blood clot, gets
wedged into an artery in your lungs. These blood clots most commonly come from the
deep veins of your legs. This condition is known as deep vein thrombosis (DVT).
In most cases, multiple clots are involved but not necessarily all at once.
Occasionally, blockages in the blood vessels are caused by substances other than blood clots, such as:
You're at higher risk if you or any of your family members have had venous blood clots or pulmonary embolism in the past. This may be due to inherited disorders that affect blood, making it more prone to clot.
In addition, some medical conditions and treatments put you at risk, such as:
Blood clots are more likely to form during periods of inactivity, such as:
Other risk factors
Pulmonary embolism can be life-threatening. About one-third of people with
and untreated pulmonary embolism don't survive. When the condition is diagnosed and
treated promptly, however, that number drops dramatically.
Pulmonary embolism can also lead to pulmonary hypertension, a condition in which the blood pressure in your lungs and in the right side of the heart is too high. When you have obstructions in the arteries inside your lungs, your heart must work harder to push blood through those vessels. This increases the blood pressure within these vessels and the right side of the heart, which can weaken your heart.
Pulmonary embolism can be difficult to diagnose, especially in people who have underlying heart or lung disease.
D dimer high levels
may suggest an increased likelihood of blood clots, although other factors can also
high D dimer levels.
Blood tests also can measure the amount of oxygen and carbon dioxide in your blood. A clot in a blood vessel in your lungs may lower the level of oxygen in your blood. In addition, blood tests may be done to determine whether you have an inherited clotting disorder.
Although X-rays can't diagnose pulmonary embolism and may even appear normal when pulmonary embolism exists, they can rule out conditions that mimic the disease.
A noninvasive test known as duplex ultrasonography (sometimes called duplex scan, or
compression ultrasonography) uses sound waves to check for blood clots in your thigh
The absence of clots reduces the likelihood of DVT. If the upper thigh vessels are clear, the ultrasonography will also scan the veins behind the knee looking for residual clots. If clots are present, treatment likely will be started immediately.
Spiral CT scan
In a spiral (helical) CT scan, the scanner rotates around your body in a spiral — like the stripe on a candy cane — to create 3-D images. This type of CT can detect abnormalities within the arteries in your lungs with much greater precision than conventional CT scans. In some cases, contrast material is given intravenously during the CT scan to outline the pulmonary arteries.
This test provides a clear picture of the blood flow in the arteries of your lungs.
most accurate way to diagnose pulmonary embolism, but because it requires a high
degree of skill to administer and has potentially serious risks, it's usually
other tests fail to provide a definitive diagnosis.
In a pulmonary angiogram, a flexible tube (catheter) is inserted into a large vein — usually in your groin — and threaded through into your heart and on into the pulmonary arteries. A special dye is then injected into the catheter, and X-rays are taken as the dye travels along the arteries in your lungs.
Treatment is aimed at keeping the blood clot from getting bigger and preventing new clots from forming. Prompt treatment is essential to prevent serious complications or death.