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Updated: Dec 8 2021

Deep Venous Thrombosis

Images
https://upload.medbullets.com/topic/120034/images/dvt.jpg
https://upload.medbullets.com/topic/120034/images/pe.jpg
https://upload.medbullets.com/topic/120034/images/vqscan.jpg
  • Snapshot
    • A 45-year-old woman presents to the emergency room for pain in her left calf. She reports flying back to the United States from Australia 2 days ago. Her flight was nonstop, making it a > 12-hour flight. She states having not worn any compression stockings and notes some swelling in the lower extremities bilaterally after the flight. She has a past medical history of hypertension and diabetes and currently takes oral contraceptive pills. Her vital signs are normal. On physical exam, her left calf is 2 cm larger in circumference than her right calf. It is also erythematous and warm with pitting edema. Her D-dimer levels are elevated.
  • Introduction
    • Clinical definition
      • blood clot in the deep veins, typically of the lower extremities
    • Associated conditions
      • pulmonary embolism
  • Epidemiology
    • Incidence
      • increases with age
    • Location
      • lower extremities
    • Risk factors
      • immobility
      • hospitalization
      • surgery
      • thrombophilia
      • malignancy
      • trauma
      • state of elevated estrogen
        • patients on estrogen for hot flashes
          • when patients develop a DVT, the hormone replacement therapy should be discontinued and alternative treatment should be started
            • e.g., SSRI and SNRI
    • Pathogenesis
      • Virchow triad puts patients at risk for DVTs
        • venous stasis
          • e.g., from long trips or bed rest
        • hypercoagulability
          • e.g., from malignancy or oral contraceptives
        • endothelial damage
          • exposed collagen will trigger the clotting cascade
          • usually secondary to lower limb trauma
  • Presentation
    • Symptoms
      • lower extremity pain and swelling
    • Physical exam
      • examination of the affected extremity
        • redness
        • warmth
        • Homan sign
          • calf tenderness with passive dorsiflexion of the foot
          • however, this is not a very useful sign
      • shortness of breath
        • may indicate pulmonary embolism
  • Imaging
    • Compression ultrasound with Doppler
      • indications
        • all patients
        • diagnostic gold standard
      • findings
        • clot formation in deep venous system
  • Studies
    • Labs
      • D-dimer
        • high sensitivity
        • low specificity
        • often used to rule out DVT
  • Differential
    • Cellulitis
      • distinguishing factors
        • no clot found on ultrasound
        • patients may have systemic signs, such as a fever
        • D-dimer is negative
  • Diagnosis
    • Making the diagnosis
      • based on clinical presentation and imaging
  • Treatment
    • Management approach
      • most patients undergo anticoagulation for 3-6 months
      • however, if the DVT is unprovoked with no identifiable cause, or if risk factors are persistent, patients may require longer periods of anticoagulation for prophylaxis of future DVTs
    • Conservative
      • appropriate prophylaxis
        • indication
          • all patients at risk for DVTs
        • modalities
          • compression stockings for long flights
          • frequent ambulation
    • Medical
      • direct oral anticoagulants
        • drugs
          • rivaroxaban
          • apixaban
        • indication
          • for outpatient management
          • useful given once/day dosing and no monitoring
      • low-molecular-weight heparin (LMWH)
        • indications
          • initial therapy
          • patients with normal renal function
      • unfractionated heparin
        • indication
          • initial therapy
          • patients with contraindications to LMWH
            • end stage renal disease
          • can be used as "bridge" to therapeutic warfarin dose
          • appropriate if > 72 hours after recent surgery
      • warfarin
        • indications
          • long-term anticoagulation
    • Operative
      • inferior vena cava (IVC) filter placement
        • indication
          • patients with contraindications to anticoagulation
  • Complications
    • Pulmonary embolism
    • Phlegmasia alba dolens
      • considered a progression from a simple DVT
      • pain, swelling, and pallor from calf all the way up the thigh
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