Pulmonary Embolism (PE)

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1- Introduction

2- Pathophysiological  Overview

3- Symptoms

4- Treatment

Introduction

Occlusion of a portion of the pulmonary vascular bed by an embolus can be a thrombus (blood clot), a tissue fragment, lipids (fats), or an air bubble. The most common emboli are thrombi dislodged from deep veins in the thigh and pelvis, termed venous thromboembolism

Pathophysiological Overview

  • The effect of the embolus depends on the extent of pulmonary blood flow obstruction, the
    size of the affected vessels, the nature of the embolus, and the secondary effects. Pulmonary emboli can occur as any of the

    following:

    1. Embolus with infarction: an embolus that causes infarction

    (death) of a portion of lung tissue

    2. Embolus without infarction: an embolus that does not

    cause permanent lung injury (perfusion of the affected

    lung segment is maintained by the bronchial circulation)

    3. Massive occlusion: an embolus that occludes a major

    portion of the pulmonary circulation (i.e., main pulmonary

    artery embolus)

    4. Multiple pulmonary emboli: multiple emboli may be

    chronic or recurrent

Symptoms

  • Sudden Onset Dyspnea: Shortness of breath that develops suddenly and may worsen with exertion.

  • Chest Pain: Often described as sharp or stabbing, worsened by deep breathing, coughing, or movement. The pain may mimic a heart attack.

  • Cough: May be dry or produce bloody sputum (hemoptysis).

  • Rapid Heart Rate: Tachycardia, especially if accompanied by palpitations.

  • Sudden Syncope: Fainting or loss of consciousness, particularly in severe cases.

  • Anxiety: Feeling of impending doom or unease.

  • Leg Swelling: Unilateral swelling of the leg (especially the calf), which may indicate deep vein thrombosis (DVT) as a precursor to PE.

  • Low Blood Pressure: Hypotension, particularly if the embolism is massive and compromises blood flow to the lungs.

  • Fever: Low-grade fever, although this is less common.

Treatment

Acute Management

  1. Anticoagulation Therapy:

    • Heparin: Given initially to prevent further blood clotting and stabilize the existing clot.
    • Low Molecular Weight Heparin (LMWH): Often used as a bridge therapy or for outpatient management.
    • Direct Oral Anticoagulants (DOACs): Such as rivaroxaban, apixaban, dabigatran, or edoxaban, are increasingly used as alternatives to heparin and warfarin.
  2. Thrombolytic Therapy (in select cases):

    • Tissue Plasminogen Activator (tPA): Used to dissolve the clot quickly in severe cases, especially when there is hemodynamic instability or massive PE.
    • Thrombolytic therapy carries higher bleeding risks and is reserved for patients with significant compromise.

Supportive Measures

  1. Oxygen Therapy:

    • Supplemental oxygen to maintain adequate oxygenation, especially if there is hypoxemia.
  2. Pain Management:

    • Analgesics to relieve chest pain, typically non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen.
  3. Monitoring:

    • Continuous monitoring of vital signs, including heart rate, blood pressure, and oxygen saturation.

Long-Term Management

  1. Anticoagulation Therapy:

    • Warfarin: May be used for long-term anticoagulation after the acute phase, especially in patients with recurrent PE or high-risk factors.
    • DOACs: Increasingly preferred due to their convenience and comparable efficacy with lower bleeding risks.
  2. Inferior Vena Cava (IVC) Filter (in select cases):

    • For patients with contraindications to anticoagulation or recurrent PE despite anticoagulation.
  3. Graduated Compression Stockings:

    • To prevent deep vein thrombosis (DVT) and reduce the risk of post-thrombotic syndrome.

Surgical Intervention

  1. Embolectomy:
    • Surgical removal of the clot, typically reserved for massive PE with hemodynamic instability or failure of medical therapy.
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