pulmonary%20thromboembolism
PULMONARY THROMBOEMBOLISM
Pulmonary embolism is the blockage of the blood vessels in the lungs usually due to blood clots from the veins, especially the veins in the legs and pelvis.
Dyspnea, chest pain, syncope or tachypnea (respiratory rate of ≥20/min) occur in most cases of pulmonary embolism.
Pleuritic chest pain with or without dyspnea is one of the most frequent presentations of this disease.
Syncope or shock are the hallmark signs of central pulmonary embolism and usually result in severe hemodynamic repercussions.
Signs of hemodynamic compromise and reduced heart flow are also usually present.

Definition

Pulmonary Embolism (PE)

  • Blockage of one or more pulmonary arteries in the lungs usually due to blood clots from the veins, especially the veins, especially the veins in the legs & pelvis

Massive Pulmonary Embolism

  • Acute PE w/ <90 mmHg systolic blood pressure (BP) for ≥15 minutes caused by PE which may or may not need inotropic therapy

Submassive Pulmonary Embolism

  • Acute PE without systemic hypotension (≥90 mmHg systolic BP) accompanied by either right ventricular (RV) dysfunction or myocardial necrosis

Signs and Symptoms

  • Suspicion of pulmonary embolism (PE) is usually raised by the clinical symptoms
  • Dyspnea, pleuritic chest pain, tachypnea (respiratory rate ≥20 breaths/minute) occur in most cases of PE
    • Dyspnea is the most frequent symptom, while tachypnea is its most frequent sign
    • Other signs & symptoms that may be present: Tachycardia [heart rate (HR) >100 beats/minute (bpm)], cough, hemoptysis, syncope, nonpleuritic chest pain, wheezing, & hypotension
  • Clinical instability or cardiac arrest is indicative of massive PE

Pleuritic Chest Pain

  • Pleuritic chest pain w/ or without dyspnea is one of the most frequent presentations of PE
    • May suggest a small embolism located distally near the pleura

Isolated Dyspnea

  • Isolated dyspnea may occur suddenly or progressively (over several weeks)
    • Usually due to a more central PE (not affecting the pleura)
    • May be associated w/ substernal angina-like chest pain that probably is representing right ventricular (RV) ischemia
    • Worsening dyspnea may be the only symptom that indicates PE in patients w/ preexisting heart failure (HF) or pulmonary disease

Syncope or Shock

  • Syncope or shock are the hallmark signs of central PE & usually result in severe hemodynamic repercussions
    • Signs of hemodynamic compromise & reduced heart flow are also usually present (eg systemic arterial hypotension, oliguria, cold extremities &/or clinical signs of acute right heart failure)

Pulmonary Embolism (PE)

  • Dyspnea is usually the prime symptom & systemic arterial hypotension that requires pressor support is the predominant sign
    • Hypotension is defined as a systolic BP <90 mmHg or a pressure drop of  ≥40 mmHg for >15 minutes if not caused by new-onset arrhythmia, hypovolemia, or sepsis
    • Syncope &/or cyanosis may be present

Massive Pulmonary Embolism (PE)

  • Hemodynamic instability
    • SBP <100 mmHg, or SBP drop to 40 mmHg; HR >110 bpm
  • Syncope
  • Severe hypoxemia
  • Respiratory distress

Risk Factors

Venous Thromboembolism (VTE)

  • The presence of risk factors for VTE in hypotensive patients should raise the possibility of pulmonary embolism (PE)
  • The probability of PE increases w/ the number of risk factors present
  • PE can also occur in individuals w/o risk factors

Primary Risk Factors

  • Antithrombin deficiency
  • Protein C deficiency
  • Thrombomodulin
  • Hyperhomocysteinemia
  • Anticardiolipin antibody
  • Prothrombin 20210A deficiency
  • Factor XII deficiency
  • Factor V Leiden (APC-R)
  • Plasminogen deficiency
  • Dysplasminogenemia
  • Congenital dysfibrinogenemia
  • Excessive plasminogen activator
  • Protein S deficiency
  • Positive history of proven VTE
  • Trauma/fractures

Secondary Risk Factors

  • Surgery
  • Advanced age
  • Central venous catheters
  • HF
  • Pregnancy/puerperium
  • Hyperviscosity (polycythemia, Waldenstrom)
  • Paresis
  • Stroke
  • Malignancy w/ or without chemotherapy
  • Obesity
  • Smoking
  • Oral contraceptives (eg Estrogen)
  • Prosthetic surfaces
  • Platelet abnormalities
  • Congenital heart disease
  • Hypertension
  • Chronic venous insufficiency
  • Long distance travel
  • Crohn’s disease
  • Lupus anticoagulant
  • Nephrotic syndrome
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