Pulmonary Embolism: Causes, Symptoms and Treatment

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Pulmonary embolism occurs when a clot blocks the blood vessels of the lung occluding its blood supply. Pulmonary embolism results in damage to lung tissue causing chest pain, shortness of breath, dizziness, or passing out. Pulmonary embolism usually occurs in combination with blood clots in the leg veins (DVT). Worldwide, there are approximately 10 million cases every year.

What actually embolism are?

Emboli are fragments of anything (usually a blood clot) that is carried away from one part of the body to another part through the route of blood. Depending upon their size they have a tendency to lodge in a suitable blood vessel. Not all pulmonary emboli are clinically significant. This is due to their small size that they never come to our notice so in 95 % of the cases they are silent that is showing no symptoms at all.

Some emboli are clinically significant due to their large size and obstructing blood flow to a large area of the lungs.

Causes of pulmonary embolism

Usually occurs in people which have an increased tendency to form clots in the body due to various predisposing conditions.

  • Bedridden and immobilized patient
  • Recent surgery
  • Obesity
  • Pregnancy:  Deep vein thrombosis occurs due to compression of veins of the leg due to baby mass in uterus, pulmonary embolism is one of the most common causes of maternal death in high socioeconomic countries.
  • Bone fracture:  Hip or long bone fracture cause fat particles to form emboli means that fat lodges in the pulmonary vessels
  • Intravenous drug abusers: They can inject a wide variety of foreign substance like hair which forms the embolus
  • Genetic factors causing the increased formation of blood clots.

The most common cause of pulmonary embolism is due to fragmented clots from the deep vein of legs normally called as deep vein thrombosis. They travel up through the bloodstream and reach the lungs vasculature by passing through the heart.

Symptoms of Pulmonary embolism

The symptoms are due to complete or partial occlusion of the blood vessel of the lungs, that causes

  • Breathlessness: Unexplained shortness of breath is sometimes the only symptom of pulmonary embolism
  • Chest pain
  • Dizziness
  • Blood in cough or expectoration
  • Rapid Heart rate

Severe cases occur when large emboli go to the lungs affecting more than 60% of the total blood supply to lungs. It can lead to

  • Loss of consciousness
  • Heart stops beating
  • Rupture of lungs blood vessels
  • Sudden death

Diagnosis of Pulmonary Embolism

  • Blood test: D-dimers levels are checked in the blood, elevated levels indicate that there is abnormal lysis of clots taking place in the body.
  • CT angiography:  This is the principal test used these days, which provides a 3D view of the blood vessels of the lung with high resolution.
  • Pulmonary angiogramThis provides the image of the blood vessels of the lungs which helps the physician to find the place of blocked blood vessels.
  • Doppler Ultrasound of the Legs: This is to identify blood clots in the legs.

Treatment of Pulmonary Embolism

Along with the specific treatment of the underlying cause like cancer, mobility issues, supportive as well as preventive measures are also required: –

  • Blood thinners: Anticoagulants that dissolve the blood clot and helps in reducing further blood clot formation. These can be injectable like heparin given through intravenous or skin injection. The patients are usually sent home on oral pills like warfarin, Xarelto, Eliquis or Pradaxa.
  • Inferior vena cava filter: This clot filter is placed in the inferior vena cava which is a large blood vessel in the abdomen which filters out emboli coming from the deep veins of the leg, suitable for high-risk people in which anticoagulants are contraindicated.

Complications of Pulmonary Embolism

Pulmonary embolism can cause death in 0.3% of the cases. Some cases with pulmonary embolism developed right-sided heart failure leading to persistent shortness of breath. Rarely people can develop high pressure in the lungs, leading to pulmonary Hypertension.

Preventive measures

Pulmonary embolism comes with a high economic burden to society due to high medical costs as well as the disability-related loss of income to the patients. Prevention becomes very important because pulmonary embolism is one of the most common reasons for preventable death worldwide. Prevention focuses on measures to reduce the risk of developing DVT.

  • Low dose anticoagulant therapy for selected cancer patients.
  • Elastic and compression stockings for legs for immobile and bedridden patients.


  • www.who.org
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  • www.isth.org