Thrombophilia in Children

Evaluation of Pediatric Thrombophilia

• Imaging depends on the symptoms (Sx)
• Laboratory tests:
  • Protein C, protein S, and ATIII may be low with acute thrombosis
  • Factor VIII may be elevated
  • Tests should be repeated if abnormal in the acute phase of disease
• Anticoagulation monitoring:
  • PTT (indirect measurement of anticoagulation)
  • Anti-Xa levels for patients receiving low molecular weight anti-coagulants (enoxaparin)
  • PT/INR for patients receiving vitamin K antagonist (warfarin)
• Additional laboratory tests:
  • CBC with platelets and fibrinogen levels
  • D-dimer

Imaging Modalities

• Doppler ultrasound:
  • Best for lower-extremity DVT
  • Decreased sensitivity for upper-extremity DVT
• Venography:
  • Helpful for upper-extremity DVT if ultrasound is negative and clinical suspicion is high
  • Requires contrast
• Spiral CT:
  • Used to evaluate for pulmonary embolism (PE)
• Magnetic resonance venography of brain:
  • Best test for sinovenous thrombosis
  • Can be missed on CT
• CT or MR angiogram/venogram:
  • Helpful for proximal thrombosis or to confirm questionable findings on ultrasound

Treatment of Pediatric Thrombophilia

• Hematology consult and ER referral for suspected thrombosis
• Anticoagulation treatment:
  • For at least 3 months or more with consideration of risk factor resolution
  • May be continued for longer periods depending on the risk factors
• Anti-Thrombolytic Agents:
  • Heparin
  • Warfarin (Coumadin):
    • Interferes with post-translational modification in vitamin K-dependent proteins
  • Enoxaparin (LMWH):
    • Small effect on the activated partial thromboplastin time
    • Strongly inhibits factor Xa
  • Dabigatran:
    • Directly inhibits thrombin
  • Rivaroxaban:
    • Directly inhibits factor Xa
  • Systemic Alteplase:
    • Used for life or limb-threatening thrombosis or submassive PE with RV dysfunction