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Basics

[Section Outline]

Author:

Alan M.Kumar

Christine A.Babcock


Description!!navigator!!

Etiology!!navigator!!

Pediatric Considerations
  • Thromboembolic disease is quite rare
  • Risk factors in children:
    • Presence of central venous catheter
    • Immobility
    • Heart disease
    • Trauma
    • Malignancy
    • Surgery
    • Infection

Diagnosis

[Section Outline]

Signs and Symptoms!!navigator!!

Essential Workup!!navigator!!

Diagnostic Tests & Interpretation!!navigator!!

Lab

  • Arterial blood gas:
    • Can show hypoxemia, hypocapnia, respiratory alkalosis, or increased alveolar-arterial (A-a) gradient
    • PE still possible with normal A-a gradient
    • Does not aid in diagnosis of PE
  • CBC:
    • Anemia may be contributing factor to dyspnea
  • d-dimer enzyme-linked immunosorbent assay:
    • d-dimers are detectable at levels >500 ng/mL in nearly all patients with PE
    • High sensitivity (close to 100%) with low specificity for PE
    • Almost always elevated in patients with malignancy or surgery within the last 3 mo
    • Multiple studies confirm that negative enzyme-linked immunosorbent assay d-dimer in combination with low clinical suspicion effectively rules out PE
    • Patients >50 yr with low pretest probability may be evaluated with age adjusted d-dimer (age adjusted d-dimer cutoff = (age × 10) mcg/L

Imaging

  • Spiral chest CT with IV contrast:
    • Has ability to also detect alternative pulmonary abnormalities
    • Accurate for identifying PE in proximal pulmonary tree:
      • In patients with high pretest probability, positive predictive value of 96%
      • In patients with low pretest probability, negative predictive value of 96%
  • Ventilation-perfusion scan (V/Q):
    • Results reported in probabilities and correlated to clinical suspicion
    • Probability of PE with V/Q results:
      • Normal or near-normal V/Q scan: 4% probability for PE
      • Low-probability V/Q scan with low clinical suspicion: 4% probability for PE
      • Low-probability V/Q scan with high clinical suspicion: 16-40% probability for PE
      • Intermediate V/Q scan: 16-66% probability for PE
      • High-probability V/Q scan with low clinical suspicion: 56% probability for PE
      • High-probability V/Q scan with high clinical suspicion: 96% probability for PE
  • Lower-extremity duplex US:
    • Used in patients who would otherwise require pulmonary angiogram
    • Presence of DVT requires same anticoagulation as PE
    • Negative lower-extremity duplex does not rule out PE
  • Echocardiogram:
    • Used to assess for right heart strain or patent foramen ovale when thrombolysis is a possibility

Diagnostic Procedures/Surgery

Pulmonary angiogram:

  • Gold stand ard for diagnosis
  • Used when diagnosis not confirmed or excluded
  • Higher complication rate than other modalities

Differential Diagnosis!!navigator!!

Treatment

[Section Outline]

Prehospital!!navigator!!

Initial Stabilization/Therapy!!navigator!!

ED Treatment/Procedures!!navigator!!

Medication!!navigator!!

Follow-Up

Disposition

Admission Criteria

  • Admit all patients with PE for continued anticoagulation and observation
  • Clinically stable patients with a high suspicion for PE, no contraindication to anticoagulation, and a lack of V/Q scanning or angiographic availability may be anticoagulated and studied when resources are available in the morning
  • New studies may suggest a role for outpatient management in select patients treated with DOAC after 24 hr

Pearls and Pitfalls

  • Clinical presentation is variable and nonspecific, making diagnosis difficult in many cases
  • Patients with malignancy are at higher risk for coumadin failure and recurrent PE even with therapeutic INR

Additional Reading

See Also (Topic, Algorithm, Electronic Media Element)

Codes

ICD9

ICD10

SNOMED