Pulmonary embolism (blood clot in the lungs)

Pulmonary embolism (blood clot in the lungs)
International Classification (ICD) I26.-



When a blood clot (thrombosis) breaks loose and is carried by the bloodstream, it can reattach itself in other blood vessels. This results in an embolism.

If the endpoint is one of the pulmonary arteries, it is called a pulmonary embolism.

The part of the lung tissue that is normally supplied by this artery receives too few nutrients and blood as a result.

Pulmonary embolisms are very common and occur in about 1-2% of all patients treated in hospital. In many cases, however, they proceed without symptoms and therefore go unnoticed.

The blood clots that cause them usually form in the lower half of the body, e.g. in the large pelvic or leg veins.


The probability of venous thrombosis is increased by a variety of (pre-) diseases, but also surgical interventions.

Thromboses are often triggered by an increase in pressure in the abdominal cavity. Even during inconspicuous activities, such as pressing on the toilet, a thrombosis can be released and subsequently become lodged in the lungs.

Risk factors:

  • altered blood clotting
  • Inactivity, long periods of sitting (e.g. travel thrombosis)
  • Surgical interventions (especially in the abdomen, hip or knee)
  • Injuries (e.g. broken bones)
  • Bedriddenness (older people and those who have just had surgery should get out of bed and move around as soon as possible).
  • Excess weight
  • Pregnancy
  • Hormonal contraceptives (pill; especially combined with tobacco use)
  • Cancer (malignant)
  • Heart failure
  • Stroke


The symptoms of a pulmonary embolism depend on the size of the clot. Small emb olisms usually remain undetected, as they rarely cause more than a brief cough.

Larger emb olisms, on the other hand, suddenly cause the following symptoms:

  • Chest pain especially when inhaling
  • Cough (also bloody)
  • sweating
  • fear, anxiety, restlessness
  • congested neck veins
  • Tachycardia (increased pulse rate)
  • Cyanosis (bluish discoloration of skin and mucous membranes due to lack of oxygen)
  • Syncope (sudden loss of consciousness)

If the blood clot is dislodged and washed away in stages, the symptoms are the same.


The attending physician takes a medical history at the beginning. He asks about complaints and previous illnesses, followed by a physical examination.

The following methods can be used:

  • ECG (electrocardiography)
  • Blood gas analysis
  • Blood sampling (to detect so-called D-dimers, an indicator of thrombosis)
  • Echocardiography (heart ultrasound)
  • Lung CT (computer tomography) with contrast medium
  • Pulmonaryscintigraphy (monitoring of ventilation and blood flow)
  • Pulmonary angiography (contrast imaging of the pulmonary vessels)
  • Doppler sonography (ultrasound of the leg veins and contrast imaging to find thrombosis)


Acute pulmonary embolism

  • Bed rest
  • Pain management
  • Oxygen administration
  • Anticoagulation with heparin (to prevent growth and formation of new clots)
  • Lysis therapy (to dissolve clots)
  • surgical removal of the clot (rare)

After acute treatment, therapy is often continued with tablets (e.g. vitamin K antagonists) or injections (heparin) until risk factors are no longer present. Lifelong treatment is also not ruled out.

If, despite treatment with medication, thromboses continue to form, which can also cause pulmonary embolisms, there is the possibility of inserting a cava screen (similar to a sieve) into the vena cava. This then prevents a clot from being flushed out into the lungs.


After a pulmonary embolism has been cured, the underlying disease must be found and treated to prevent further thromboses.

About 17% of those affected suffer a relapse. More rarely, chronic pulmonary hypertension can occur.

3-4% succumb to pulmonary embolism.

Possible complications:

  • Pleurtis (inflammation of the pleura)
  • pulmonary infarction (death of the affected area of the lung) and bloody cough
  • Pneumonia (inflammation of the lungs)
  • Right heart failure


The risk of pulmonary embolism can be influenced by treatment of the underlying disease and various risk factors.

  • Postoperative: mobilisation as soon as possible, physiotherapy.
  • Bedriddenness and immobility: anticoagulant medication
  • Long journeys: regular movement of the feet, e.g. by circling or rocking.
  • Tendency to thrombosis: Compression bandages or stockings
  • Avoidance of strict bed rest
  • Avoidance of hormonal contraceptives (those containing oestrogen)

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All information used for the content comes from verified sources (recognised institutions, experts, studies by renowned universities). We attach great importance to the qualification of the authors and the scientific background of the information. Thus, we ensure that our research is based on scientific findings.
Danilo Glisic

Danilo Glisic

As a biology and mathematics student, he is passionate about writing magazine articles on current medical topics. Due to his affinity for facts, figures and data, his focus is on describing relevant clinical trial results.

The content of this page is an automated and high-quality translation from DeepL. You can find the original content in German here.



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