Pulmonary embolism

The main warning signs are sudden or gradual onset of shortness of breath, sometimes there is also respiratory pain in the chest. However, pulmonary embolism is often preceded by leg swelling or a period of immobilization or inflammatory disease.

What is a pulmonary embolism?

Pulmonary emboli, are blood clots (thrombus) that can partially or completely occlude blood vessels in the lungs. Such thrombi develop in the form of venous thrombosis, often in the leg vessels, and are carried with the bloodstream to the lungs. Such a ruptured or carried blood clot is called an embolus by experts. The words “embolism” and “embolus” are derived from the Greek word “embole”. Translated, it means “penetration”.

Once in the lungs, that part of the lung normally supplied by the clogged vessel is no longer supplied with sufficient blood, or any blood at all. On the one hand, this has the consequence that the gas exchange in the lungs is restricted and thus the body and the organs are no longer supplied with sufficient oxygen and nutrients. In addition, cardiac stress may occur as a result of the vascular blockage because the right heart has to pump against increased resistance (blocked vasculature).

A small pulmonary embolism with blockage of a few pulmonary vessels may go unnoticed. The greater the thrombus burden and the more pulmonary vessels are blocked, the more dangerous pulmonary embolisms are. In the case of bilateral involvement of many pulmonary vessels, pulmonary embolism can be life-threatening; usually as a result of acute heart failure. Therefore, it is important to immediately notify the emergency services in case of alarm signs – chest pain, palpitations, shortness of breath – to get clarified and, if necessary, treated.

Across Europe, experts estimate the number of deaths from acute pulmonary embolism to be as high as 370,000 yearly. Some affected individuals do not survive the first two hours after the onset of symptoms in severe cases.

Pulmonary embolism: causes and risk factors

The origin of pulmonary embolisms is usually a blood clot that has formed elsewhere in the body and is washed from there into the lungs. In about 90 percent of cases, the thrombus develops in the pelvic and leg veins. The blood clot can detach, it is washed away with the blood flow to the right side of the heart and from there towards the pulmonary arteries. In the lungs, the usually multiple clots then block the blood vessels, causing the various symptoms. Even though a blood clot is the most common cause of pulmonary embolism, there are several other reasons: fat particles, amniotic fluid, air bubbles, cells, and foreign bodies.

Pulmonary embolism and thrombosis: Three mechanisms are at work

There are three factors that promote the formation of blood clots (and thus pulmonary embolism).

• Reduced flow rate of blood: in case of lack of exercise due to prolonged sitting or bedriddenness, serious illnesses, lower leg casts, long air and car journeys or after operations – the calf muscle pump is not activated enough.
• Increased tendency of the blood to clot: The composition of the blood may be altered, for example in the case of coagulation disorders, tumor diseases, inflammatory diseases or the use of hormonal contraceptives.
• Injuries, changes or inflammations of the innermost vein wall layer

Risk factors for thrombosis and pulmonary embolism

Experts know of several risk factors that increase the risk of thrombosis, and in turn pulmonary embolism, to varying degrees – an overview of the most important factors.

High risk of thrombosis

• Major / prolonged operations (e.g. orthopedic surgery)
• previous thrombosis or pulmonary embolism

Medium risk of thrombosis

• Taking hormones
• Plaster cast with limited mobility of the ankle joint
• medium size operations
• Chronic heart failure, previous heart attack
• Chronic lung diseases

Low risk of thrombosis

• Bed rest for more than three days
• Pregnancy and postpartum
• Strong varicose veins

Symptoms: pulmonary embolism

The symptoms of pulmonary embolism correlate with the number of clots and thus the extent of the affected pulmonary vessels. If the thrombus burden is small and only a small area is affected, the pulmonary embolism often causes only exertion-dependent dyspnea and mild and nonspecific symptoms or goes unnoticed at first, often followed by repeated emboli. If, on the other hand, blood clots block several pulmonary vessels, even large ones, respiratory distress at rest becomes increasingly apparent and there is a danger to life. In this case, part of the lung is cut off from the supply of oxygen and nutrients. In the event of resting respiratory distress, affected persons must therefore notify the emergency medical services immediately.

In general, the symptoms of pulmonary embolism are nonspecific and may also occur in the context of other diseases. In addition, the extent of the symptoms varies greatly from individual to individual.

The following alarm signs may indicate pulmonary embolism:

• Increasing shortness of breath, at first only on exertion, then also at rest
• Abrupt dyspnea and shortness of breath, accelerated breathing
• Fast heartbeat, palpitations
• Breath-dependent chest pain, chest pain
• Cough, sometimes with bloody sputum
• massive fears – up to the fear of death
• Sweating
• Blood pressure drop, circulatory weakness, dizziness, lightheadedness, circulatory shock and fainting.

In the case of deep vein thrombosis, swelling, redness, and hyperthermia can often be seen in the extremity where the thrombosis is located. In addition, there may be pain, heaviness or a feeling of tightness in the affected extremity.

Important: Severe shortness of breath at rest, possibly combined with a feeling of weakness or pain in the chest area, is always an emergency in which you must call the emergency services on 144 immediately!

Pulmonary embolism: diagnosis with us

The diagnosis of pulmonary embolism always begins with a discussion between a physician and the patient about the patient’s medical history. For example, the following questions are important:

• What exactly are your complaints, since when and what was the course?
• How intense are the complaints?
• Have you had a thrombosis or pulmonary embolism before?
• Have you recently been bedridden for a long time, for example after surgery?
• Do you smoke?
• Do you take hormones, for example contraceptives?
• Do you have any known medical conditions, for example, clotting disorders, cancer, chronic heart or lung disease?

Your answers already provide us with initial clues as to whether a pulmonary embolism could be the culprit behind the symptoms.

Physical examination and other diagnostic methods

Physical examination with determination of vital signs (blood pressure, pulse) may provide clues to possible pulmonary emboli or other diseases causative of the complaints.

To assess the likelihood of pulmonary embolism, we use a scoring system called the Wells or Geneva score. Seven parameters from the physical examination and the medical history are included:

1. Is there evidence of thrombosis? Yes = 3 points
2. Is pulmonary embolism more likely than another cause/disease? Yes = 3 points
3. Heartbeat: Is it faster than 100 times per minute? Yes = 1.5 points
4. Has there been surgery or strict bed rest in the last four weeks? Yes = 1.5 points
5. Has thrombosis or pulmonary embolism ever occurred? Yes = 1.5 points
6. Does the sputum contain blood admixtures? Yes = 1 point
7. Is there or has there been a cancer in the last six months? Yes = 1 point

Zero to two points indicates a low probability of pulmonary embolism, two to six points indicates a moderate probability, and more than six points indicates a high probability.

Treatment begins immediately if the results of these tests suggest a high probability of pulmonary embolism.

Blood test (D-dimer test)

Sometimes the initial test results are inconclusive. This is followed by a blood test in which we determine the so-called D-dimers (D-dimer test). D-dimers are cleavage products of the protein fibrin, which plays a key role in the formation of blood clots. The body forms D-dimers when it tries to dissolve the blood clot itself, but D-dimers can also be present in other inflammatory diseases.

We also determine other blood values, such as troponin and brain natriuretic peptide, abbreviated BNP. These are proteins produced by the heart. In pulmonary embolism, these values may be elevated as a result of cardiac stress.

Further examinations in pulmonary embolism

Diagnosis of pulmonary embolism requires computed tomography (CT)/CT angiography with contrast. Radiologists administer a contrast medium and then produce a three-dimensional image of the chest. In this way, emboli of the pulmonary vessels can be visualized.

In addition, we consult other studies to estimate the severity. The most important are:

• Heart ultrasound (echocardiography): We can assess the condition of the right heart, such as whether it is pumping normally or is enlarged (congested)
• Lung scintigraphy: Lung scintigraphy works with a low-level radioactive substance that is injected into their vein, sometimes combined with a substance that the patient inhales. Pulmonary scintigraphy allows conclusions about blood flow and ventilation and may be important for clarifying chronic pulmonary emboli during progression (rarely used)
• Ultrasound (sonography) of the leg and pelvic veins to detect thrombosis in this area
• Magnetic resonance imaging/MR angiography: its informative value in the diagnosis of pulmonary embolism is not yet sufficiently proven. Only special centers have this technology, which is why it is not used nationwide.

Pulmonary embolism: prevention, early detection, prognosis

In most cases, a pulmonary embolism is the result of a blood clot in the deep veins of the legs and pelvis. With the right thrombosis prophylaxis, you can start here yourself. If you prevent thrombosis, you can also prevent pulmonary embolism.

Some tips:

• If you are bedridden, try to get up a little each day or at least keep moving your legs/feet to help stimulate blood flow and your circulation. Ask us if you really need to follow strict bed rest. Otherwise, regular foot exercises (tensing the calf muscles, lifting, lowering and circling the tips of the feet) and elevating the legs can also help.
• After surgery, compression stockings reduce the risk of thrombosis. They exert pressure on the leg and ankle from the outside. Compression stockings also help during longer trips when you cannot move around enough.
• When traveling, always try to exercise in between. Walk back and forth a few steps on the bus, train or plane. On road trips, get out of the car often and take a walk.
• If you do not suffer from heart disease, drink a lot! At least 1.5 to two liters per day are advisable. Water, tea or fruit juice spritzers are good. Consume only little alcohol and coffee, as they promote fluid loss.
• Refrain from smoking. This is especially true if you are taking hormones at the same time.
• Maintain a healthy body weight and avoid being overweight or obese.
• With vein gymnastics, you promote blood flow in the legs and prevent varicose veins.
• Anticoagulant medications can prevent pulmonary embolism. They are suitable for people at increased risk of thrombosis in high-risk situations.

Course and prognosis in pulmonary embolism

The course and prognosis of pulmonary embolism depend on several factors:

• the severity of the pulmonary embolism,
• Your age,
• Your general health,
• existing underlying diseases and
• how quickly the treatment kicks in.

Pulmonary embolism treatment

Lungenembolien sind in der überwiegenden Mehrheit der Fälle gut mittels blutverdünnenden Medikamenten behandelbar und heilen meist folgenlos wieder aus. Ausgedehntere Lungenembolien mit Befall von grösseren Blutgerinnsel können dagegen lebensgefährlich werden. Some do not survive the first few hours after the onset of symptoms. This is why prompt diagnosis or treatment of pulmonary embolism is so important. Then there is a possibility that you will fully recover.

Those who have experienced pulmonary embolisms once are also at increased risk for further embolisms. If, despite treatment of pulmonary embolism with blood thinning, you still have symptoms after three to six months, you should definitely seek medical treatment. A pulmonary embolism can lead to other complications and consequences. These include, for example, a pulmonary infarction, pneumonia, cardiac arrhythmia or heart failure due to the increased strain on the right heart. Long-term complications include fatigue and exertional dyspnea.