Detailed Notes on Embolism

Definition of Embolism
  • Embolism: An intravascular mass that travels through the bloodstream and occludes a blood vessel.
Types of Emboli
  1. Thromboembolus
  • Most common type of embolus.
  • Formed when a thrombus (blood clot) breaks away and floats through the bloodstream, eventually lodging elsewhere.
  1. Atherosclerotic Embolus
  • Arises from atherosclerosis where a piece of plaque dislodges and travels through the bloodstream.
  • Characterized by cholesterol clefts in the embolus, indicating its origin from atherosclerotic plaque.
  1. Fat Embolus

  • Associated with trauma, especially bone fractures, where fat is released into the bloodstream.

  • Commonly develops shortly after injury (-3 days).

  • Classic symptoms: dyspnea, petechiae on the chest.

  • Common location: blood vessels of the lung.

    Fat Embolus

  1. Gas Embolus
  • Often seen in decompression sickness when nitrogen from the blood precipitates out as gas bubbles during rapid ascent while diving.
  • Symptoms: joint pain (the bends) and respiratory symptoms (the chokes).
  • Can also occur after laparoscopic surgery due to air entering the bloodstream.
  1. Amniotic Fluid Embolus
  • Occurs during labor/delivery when amniotic fluid enters maternal circulation, commonly affecting the lungs.
  • Symptoms: shortness of breath, neurological symptoms, and DIC (disseminated intravascular coagulation).
  • Characteristic findings in the emboli: squamous cells and keratin debris.
Pulmonary Embolism (PE)
  • Commonly arises from thromboembolism due to DVT (deep vein thrombosis), especially from lower extremities.
  • Usually clinically silent due to:
  • Dual blood supply of the lungs (pulmonary and bronchial arteries).
  • Most emboli are small and self-resolving.
Clinical Signs of Pulmonary Infarction
  • Potential indicators of pulmonary infarction from PE include:
  • Shortness of breath
  • Hemoptysis (coughing blood)
  • Pleuritic chest pain
  • Pleural effusion
  • Diagnostic tests:
  • V/Q scan: Ventilation-perfusion mismatch.
  • Spiral CT: Vascular filling defect indicates embolus.
  • Doppler ultrasound: Detects DVT origins.
  • D-dimer test: Elevated due to thrombus breakdown.
  • Gross exam: Hemorrhagic wedge-shaped infarct due to lung anatomy (branching blood supply).
Complications of PE

  • Sudden death can occur due to massive embolism (e.g., saddle embolus).

  • Electromechanical dissociation results in heart pumping without blood flow.

  • Chronic pulmonary embolism can lead to pulmonary hypertension as emboli get reorganized over time.

Systemic Emboli
  • Source: Most commonly arise from thromboemboli from the left heart and lodge in the systemic circuit, especially affecting lower extremities.