Deep Vein Thrombosis (DVT)

Overview

• DVT is a condition involving thrombus (blood clot) formation within the deep veins, often in the lower legs.
• Common in patients:
  • Postoperative
  • Immobile
  • With chronic illnesses
  • Bedbound
• Complication: Can lead to pulmonary embolism (PE), a life-threatening condition.

Signs and Symptoms of DVT

• Asymmetrical leg symptoms:
  • Edema (swelling)
  • Calf swelling
  • Localized pain
• Signs of PE may also be present.

Pathophysiology

• Normal vein function: Valves prevent backflow and assist blood return to the heart.
• DVT: Thrombus forms in the veins, possibly leading to:
  • Propagation (growth)
  • Organization (incorporation into vessel)
  • Recanalization (formation of new channels)
  • Embolism (dislodgement, causing PE)
  • Resolution (breakdown by the body)

Causes and Risk Factors

• Virchow's Triad: Three main factors contributing to DVT:
  1. Vessel injury
  2. Venous stasis
  3. Hypercoagulability
• Risk factors include:
  • Pregnancy
  • Advanced age
  • Obesity
  • Malignancy
  • Recent major surgery
  • Medical comorbidities
  • Hospitalization
  • Certain medications (e.g., oral contraceptives)
  • Long-distance flights
  • Genetic predispositions (e.g., Protein C and S deficiency)

Investigations

• Blood Tests: Full blood count, liver function test, electrolytes, INR (clotting studies)
• Imaging:
  • Venous duplex ultrasound
  • Chest imaging if PE is suspected
• Coagulation Studies:
  • Coagulation cascade involves extrinsic and intrinsic pathways leading to thrombin and fibrin formation.
  • D-dimer: A marker of coagulation activity; elevated in active thrombosis but not specific to DVT.

Management

• Anticoagulants:
  • Heparin (low molecular weight or unfractionated)
  • Warfarin (requires INR monitoring)
• Prophylaxis:
  • Important for surgical patients
  • Includes compression stockings and physical activity to prevent PE