Pulmonary Embolism (PE)-Full information

Pulmonary embolism (PE) is a potentially life-threatening condition that occurs when a blood clot forms in one of the pulmonary arteries, blocking blood flow to the lungs. Here’s an overview of the pathophysiology, symptoms, causes, risk factors, complications, diagnosis, treatment, and prevention of pulmonary embolism:

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Pathophysiology: Pulmonary embolism usually arises from deep vein thrombosis (DVT), where a blood clot forms in the deep veins of the legs or pelvis. The clot, known as a thrombus, can dislodge and travel through the bloodstream until it becomes lodged in the pulmonary arteries, blocking blood flow. This obstruction can impair the exchange of oxygen and carbon dioxide in the lungs, leading to decreased oxygen levels in the body.


The symptoms of pulmonary embolism can vary in severity, depending on the size of the clot and the extent of the obstruction. Common symptoms include sudden onset of:

  1. Shortness of breath
  2. Chest pain (sharp, stabbing, or pleuritic)
  3. Rapid or irregular heartbeat
  4. Cough, sometimes with blood-tinged sputum
  5. Sweating
  6. Lightheadedness or fainting
  7. Leg pain or swelling (associated with deep vein thrombosis)


The most common cause of pulmonary embolism is the migration of a blood clot from a deep vein in the leg or pelvis. Other potential sources of emboli include the upper extremities, right heart chambers, or paradoxical emboli from a patent foramen ovale (a hole in the heart). Fat embolism, air embolism, and amniotic fluid embolism are rare causes of pulmonary embolism.

Risk Factors:

Several factors increase the risk of developing pulmonary embolism. These include:

  1. Prolonged immobilization (bed rest, long flights, etc.)
  2. Recent surgery or trauma
  3. Cancer and its treatment
  4. Hormonal factors (such as pregnancy, birth control pills, and hormone replacement therapy)
  5. Obesity
  6. Smoking
  7. Older age
  8. Inherited or acquired clotting disorders


Pulmonary embolism can lead to various complications, including:

  1. Pulmonary infarction: Death of lung tissue due to lack of blood supply.
  2. Pulmonary hypertension: Increased blood pressure in the pulmonary arteries, which strains the heart.
  3. Right heart strain or failure: The heart has to work harder to pump blood against increased resistance.
  4. Recurrent embolism: Formation of additional blood clots in the pulmonary arteries.
  5. Death: In severe cases, pulmonary embolism can be fatal.

Differential diagnoses (PE):

When diagnosing pulmonary embolism (PE), healthcare professionals consider several differential diagnoses – conditions that share similar symptoms but require different treatments. It is crucial to rule out these alternative conditions to ensure an accurate diagnosis. Here are some common differential diagnoses for PE:

Cardiac conditions:

  • Acute coronary syndrome (unstable angina or myocardial infarction)
  • Pericarditis
  • Aortic dissection
  • Heart failure

Respiratory conditions:

  • Pneumonia
  • Pleurisy
  • Pneumothorax
  • Asthma exacerbation
  • Chronic obstructive pulmonary disease (COPD) exacerbation

Pulmonary conditions:

  • Pulmonary edema
  • Pulmonary hypertension
  • Pulmonary embolism of a different origin (air, fat, amniotic fluid)
  • Pulmonary infection (e.g., lung abscess)

Gastrointestinal conditions:

  • Peptic ulcer disease
  • Gastroesophageal reflux disease (GERD)
  • Biliary colic
  • Pancreatitis

Musculoskeletal conditions:

  • Costochondritis
  • Rib fracture

Neurological conditions:

  • Transient ischemic attack (TIA)
  • Stroke

Anxiety and panic disorders:

  • Panic attacks
  • Generalized anxiety disorder

These are just some of the conditions that can present with symptoms similar to PE. Differential diagnosis involves a comprehensive evaluation of the patient’s medical history, physical examination, laboratory tests (e.g., D-dimer, arterial blood gas), imaging studies (e.g., chest X-ray, CT angiography), and other diagnostic procedures to confirm or exclude the presence of PE. It’s important to consult a healthcare professional for a proper evaluation and diagnosis.


Diagnosing pulmonary embolism typically involves a combination of the following:

  1. Medical history and physical examination
  2. Blood tests (such as D-dimer, a marker of blood clot formation)
  3. Imaging tests, including computed tomography pulmonary angiography (CTPA), ventilation-perfusion (V/Q) scan, or Doppler ultrasound of the legs to detect deep vein thrombosis.


  1. Anticoagulant therapy: Anticoagulant medications, such as heparin or warfarin, are typically used as the primary treatment for pulmonary embolism. These medications help prevent further clot formation and allow the body’s natural mechanisms to dissolve the existing clot. The duration of anticoagulant therapy may vary depending on the individual’s risk factors and the severity of the PE.

  2. Thrombolytic therapy: In severe cases of pulmonary embolism, where there is significant obstruction of blood flow or hemodynamic instability, thrombolytic therapy may be used. This involves administering medications such as alteplase or reteplase to dissolve the blood clot more rapidly.

  3. Inferior vena cava (IVC) filter placement: In certain situations where anticoagulant therapy is contraindicated or ineffective, an IVC filter may be placed. The filter is inserted into the large vein in the abdomen (inferior vena cava) and catches blood clots before they reach the lungs. This prevents further embolization, but it does not treat the existing clot.


  1. Medication: For individuals at high risk of developing blood clots, anticoagulant medications may be prescribed as a preventive measure. This is common in cases of deep vein thrombosis (DVT), a condition that often precedes pulmonary embolism. Medications may be recommended for individuals undergoing surgery, immobilized due to illness or injury, or with a history of blood clots.

  2. Compression stockings: Wearing compression stockings can help prevent blood clots from forming in the lower legs. These stockings exert gentle pressure on the legs, improving blood flow and reducing the risk of clot formation.

  3. Early ambulation: After surgery or prolonged periods of immobility, it is important to get up and move around as soon as possible. Early ambulation helps prevent blood stasis in the legs and reduces the risk of blood clots.

  4. Avoiding prolonged sitting or standing: Individuals who are prone to blood clots should avoid sitting or standing for long periods. Regular movement, stretching, and changing positions can help maintain healthy blood circulation.

  5. Hydration: Staying well hydrated is essential for preventing blood clots. Sufficient fluid intake helps maintain blood viscosity and prevents the blood from becoming too thick, reducing the risk of clot formation.

It’s crucial to consult with a healthcare professional for an accurate diagnosis, appropriate treatment, and personalized prevention strategies for pulmonary embolism.