Medical Musing of the Week: Pulmonary Embolism

Overview

  • Thrombus of the pulmonary artery or branches
  • MCC from lower extremity DVT
  • 12% without unclear etiology result in malignancy diagnosis

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Etiology/Risk Factors

  • Virchow’s Triad: Venous stasis, endothelial injury and hypercoagable state
  • Hip replacement/fracture is a large risk factor (and other surgeries!)
  • Clotting disorders (Factor V Liden is MC), pregnancy

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Clinical Manifestations

  • MC symptom is dyspnea
  • Pleuritic chest pain
  • Hemoptysis
  • Tachycardia (on a personal note I had a bradycardic patient with a PE last week!)
  • Cough
  • If PE is massive/saddle (spanning both main pulmonary arteries) pt can be very unstable or even unresponsive
  • Typically this is a patient that

Diagnostic Studies

  • D-Dimer is VERY non-specific.Β  Only perform if you have low suspicion of PE
  • CT PE is most common study used clinically (need good kidneys)
  • V-Q scan if bad kidneys
  • GOLD STANDARD (boards buzz word!) Pulmonary Angiography
    • Used when CT PE negative but still have high suspicion
    • Clinically I have never seen one of these ordered.Β  If you have that high of a suspicion and you cannot properly investigate you TREAT!
  • EKG: S1Q3T3, sinus tachycardia
  • CXR is most commonly normal
    • Hamptons Hump
      • Represents an infarcted area of the lung secondary to thrombus blocking vasculature
    • Westermark Sign
      • Lack of vascular markings distal to the emboli

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Treatment

  • Unstable patient: Immediate surgery for embolectomy
  • Hemodynamically stable patient:
    • Heparin gtt w/ bridge to coumadin
      • 80 unit bolus
      • 18u/kg/hr
      • PTT goal 1.5-2x control value
      • INR of 2.0 or greater for 24 hours before d/c heparin
    • Lovenox with bridge to Coumadin
      • 1mg/kg SC BID
      • INR of 2.0 or greater for 24 hours before d/c lovenox
    • Xarelto
      • 15mg PO BID x 21 days; followed by 20mg PO daily
    • Eliquis
      • 10mg PO BID x 7 days; followed by 5mg PO BID
    • IVC filter in patients who cannot receive OAC (maybe they are a high fall risk or their HAS-BLED score is super high)
  • Duration of treatment with OAC depends on if provoked, unprovoked, underlying pathology, etc.
    • Provoked (surgery, pregnancy): 3 months
    • Unprovoked: 6 months (or longer)
    • Recurrent unprovoked: Likely life-long OAC

Complications, Prognosis & Stuff to know!

  • Check PT/INR/PTT daily
  • Watch for bleeding (obviously!)
  • Can do PPI for GI protection
  • Protamine Sulfate is the antidote for Heparin and Lovenox
  • Don’t use heparin with bad liver and don’t use Lovenox with bad kidneys
  • Be highly suspicious of malignancy in a patient who appears to have no other risk factors for PE
  • Remember to ask if pt has had prior DVT/PE (very important!)
  • Does the patient have a new oxygen requirement?
  • How does their breathing look?
  • Do you need a transfer to a higher level of care?
  • If early PE is not caught, subsequent PE’s are associated with a higher fatality rate so it is very important to catch that first one early and treat!

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