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Pulmonary Embolism

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There is a high mortality rate associated with missed diagnosis (30% vs 2-8 ... 80% of patients have an abnormal electrocardiogram. ... – PowerPoint PPT presentation

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Title: Pulmonary Embolism


1
Pulmonary Embolism
  • Meghan Rothenberger
  • March, 2007

2
Background
  • PE causes 50,000 100,000 deaths per year.
  • The diagnosis is notoriously difficult to makeit
    is estimated that gt50 of PEs are missed.
  • There is a high mortality rate associated with
    missed diagnosis (30 vs 2-8 when PE diagnosed
    and treated early).
  • Despite the number of missed cases, PE is found
    in only 25-35 of patients in whom the diagnosis
    is consideredtherefore this disease is
    under-diagnosed but over-investigated.

3
Symptoms
  • In a large prospective study, the most common
    symptoms were
  • Shortness of breath (73 of patients).
  • Pleuritic chest pain (66)
  • Cough (37)
  • Hemoptysis (16) hemoptysis was rarely massive.
  • Other symptoms
  • New onset of wheezing.
  • Palpitations.
  • Lightheadedness, syncope.
  • Sx to suggest DVT (present in lt30 of patients).
  • The classic triad of hemoptysis, dyspnea, and
    chest pain occurs in lt20 of patients with PE.
  • Patients may actually have very minimal symptoms.

4
History
  • When taking history, dont forget to ask about
    risk factors for DVT/PE such as
  • Immobilization
  • Recent surgery (within 3 months)
  • Malignancy
  • OCP or estrogen receptor modulator use
  • Smoking
  • Family history of PE/DVT
  • Previous DVT/PE
  • Pregnancy/post partum state
  • Lower extremity trauma
  • Heart failure

5
Physical Exam
  • In patients with recognized PE, the incidence of
    physical signs has been reported as follows
  • Tachypnea 70
  • Rales 51
  • Accentuated pulmonic component of S2 23
  • Circulatory collapse 8
  • Fever (temperature usually lt102.0ºF/38.9ºC) 14
  • Other physical Exam findings
  • Tachycardia
  • Diaphoresis
  • S3 or S4 gallop
  • Cyanosis
  • LE edema, erythema, tenderness

6
Work up
  • If you suspect PE, a clinical prediction scale
    such as the Wells Criteria or Geneva Score should
    be used to help to determine work up and
    interpretation of imaging.
  • Wells does not require ABG, so it is easier to
    use than Geneva.

Criteria for the calculation of the Wells
score
Classic score lt2 indicates low probability
of PE 26 moderate probability of PE
gt6 high probability of PE. Simplified score
lt4 unlikely gt4 likely
7
Work up

  • Check CBC, chemistry panel, coags in all
    patients.
  • Other studies to consider
  • D Dimer
  • do NOT check in patients with high clinical
    probability (see algorithm on next slide).
  • high negative predictive value - elevated in 97
    of patients with PE
  • but nonspecific - 48.8 of positives do not have
    PE
  • EKG
  • gt80 of patients have an abnormal
    electrocardiogram.
  • Abnormalities are usually minor, nonspecific, and
    transient.
  • Sinus tachycardia is most common.
  • S1, Q3, T3 pattern classic but rarely seen.

8
Work up
  • Specific studies to consider, cont
  • CXR
  • Up to 40 of patients with pulmonary embolism
    have a normal chest X-ray
  • ABG
  • 85 of patients with angiographically proven
    pulmonary embolism have normal pO2 levels.
  • Troponins
  • Elevated in 3050 of patients with moderate to
    large PE.
  • High troponins associated with poor outcomes.

9
Work up
  • Need for imaging determined by clinical
    prediction scale.
  • If imaging indicated, CT angiogram is preferred
    to V/Q scan, as long as there are no
    contraindications (such as renal failure).

Wells lt4 unlikely Wells gt4 likely
CT based algorithm
10
Work Up
  • If V/Q is only option, dont forget to take into
    account pre-test probability when interpreting
    results

Likelihood of pulmonary embolism according to
scan category and clinical probability in PIOPED
study
Data from PIOPED Investigators, JAMA 1990
2632753.
11
Management Massive PE
  • Defined as PE with cardiogenic shock.
  • Start unfractionated heparin IMMEDIATETLY.
  • Use fluids with caution.
  • Low threshold to start pressors.
  • Systemic thrombolysis should be given if no
    contraindications.
  • Prior to starting thrombolytics, dont forget to
    d/c heparin.
  • If systemic thrombolysis is contraindicated,
    consider percutaneous catheter thrombectomy or
    surgical embolectomy.

Large PE on CT angiogram
12
Management - PE without shock
  • Thrombolytics should NOT be used as first line
    treatment in non-massive PE.
  • Start heparin prior to imaging if clinical
    suspicion high.
  • Unfractionated heparin should be used for massive
    PE or in situations when rapid reversal of
    anticoagulation may be required.
  • Otherwise, low molecular weight heparin can be
    used.
  • Start oral anticoagulation therapy once PE
    confirmed with imaging.

13
One approach to hypercoagulable work up
  • If someone is weakly thrombophilic (first clot
    gtage 50 AND negative family history) consider
    checking
  • Factor V Leiden
  • Antithrombin mutation
  • Activated protein C resistance
  • Homocysteine
  • Antiphospholipid antibodies
  • Keep in mind that acute clot, heparin, and
    warfarin can interfere with many of these assays.
  • This is a controversial issue, so dont forget to
    use clinical judgement in deciding appropriate
    w/u for hypercoagulability.
  • Not needed if there is obvious risk factor
    (cancer, recent surgery).
  • If someone appears to be highly thrombophilic
    (first clot lt50yo, multiple clots, or 1st degree
    relative with clot lt50yo) check
  • Factor V Leiden
  • Prothrombin mutation
  • Activated protein C resistance
  • Homocysteine
  • Antiphospholipid antibodies
  • Antithrombin deficiency
  • Protein C and S deficiency.

14
References
  • Feied CF Pulmonary embolism. In Rosen and
    Barkin, eds. Emergency Medicine Principles and
    Practice. Vol 3. 4th ed. 1998chap 111.
  • Stein, PD, Terrin, ML, Hales, CA, et al.
    Clinical, laboratory, roentgenographic and
    electrocardiographic findings in patients with
    acute pulmonary embolism and no pre-existing
    cardiac or pulmonary disease. Chest 1991
    100598.
  • Stein, PD, Saltzman, HA, Weg, JG. Clinical
    characteristics of patients with acute pulmonary
    embolism. Am J Cardiol 1991 681723.
  • Hogg K, Brown G, Dunning J, et al Diagnosis of
    pulmonary embolism with CT pulmonary angiography
    a systematic review. Emerg Med J 2006 Mar 23(3)
    172-8
  • Kabrhel C, Matts C, McNamara M, et al A Highly
    Sensitive ELISA D-Dimer Increases Testing but Not
    Diagnosis of Pulmonary Embolism. Acad Emerg Med
    2006 Mar 21
  • Le Gal G, Righini M, Roy PM, et al Prediction of
    pulmonary embolism in the emergency department
    the revised Geneva score. Ann Intern Med 2006 Feb
    7 144(3) 165-71
  • Brown MD, Rowe BH, Reeves MJ, et al The accuracy
    of the enzyme-linked immunosorbent assay D-dimer
    test in the diagnosis of pulmonary embolism a
    meta-analysis. Ann Emerg Med 2002 Aug 40(2)
    133-4
  • Writing Group for the Christopher Study
    Investigators Effectiveness of Managing
    Suspected PE Using an Algorithm Combining
    Clinical Probability, D-Dimer Testing, and
    Computed Tomography. JAMA, Jan 11, 2006-Vol 295,
    No. 2
  • Kucher, N and S. Goldhaber. Management of Massive
    Pulmonary Embolism. Circulation. 2005112e28-e32
  • British Thoracic Society guidelines for the
    management of suspected acute pulmonary embolism.
    Thorax. 2003 Jun58(6)470-83.
  • Mateo, J, Oliver, A, Borrell, M, et al.
    Laboratory evaluation and clinical
    characteristics of 2,132 consecutive unselected
    patients with venous thromboembolism results of
    the Spanish Multicentric Study on Thrombophilia
    (EMET-Study). Thromb Haemost 1997 77444.
  • Heijboer, H, Brandjes, DP, Buller, HR, et al.
    Deficiencies of coagulation-inhibiting and
    fibrinolytic proteins in outpatients with deep
    vein thrombosis. N Engl J Med 1990 3231512.
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