Deep Vein Thrombosis

Basics

Description

  • A constant balance exists between intravascular clot formation and clot dissolution, clot forming when the former overpowers the latter
  • Clot can be superficial (to the fascia) or deep. The latter is called deep vein thrombosis (DVT)
  • Pulmonary embolism (PE) and DVT are different ends of the clinical spectrum of the same disease process (venous thromboembolism, VTE)
  • DVT can be upper or lower extremity, as well as distal or proximal. Upper-extremity DVT accounts for up to 4% of all diagnosed DVTs
  • Incidence is ∼2 first time VTE episodes per 1,000 person yr
  • Prevalence increases with advancing age
  • Common in both medical and surgical hospitalized patients
  • Diagnosis is more accurate using active surveillance rather than clinical suspicion

Pediatric Considerations
DVT in children is unusual, but when cases do occur, search for an underlying reason for hypercoagulability. Also, upper-extremity DVT is associated with central IV lines in children

Etiology

  • Clot formation/dissolution is an intricately balanced system which can be influenced by many factors which must be considered
  • Virchow's triad: hypercoagulable state, venous stasis, vascular injury
  • Hypercoagulable states (often multiple concomitant):
    • Cancer (particularly lung, pancreas, colorectal, kidney and prostate)
    • Myeloproliferative disorders
    • Nephrotic syndrome
    • Sepsis
    • Inflammatory conditions:
      • Ulcerative colitis, Crohn disease
    • Hormone alterations:
      • Pregnancy
      • Exogenous hormones (OCPs, HRT)
      • Testosterone supplements
    • Antiphospholipid syndrome
    • Protein S, C, and antithrombin deficiencies, factor V Leiden, prothrombin gene mutations, lupus, others
  • Stasis:
    • Prolonged bed rest
    • Immobility (such as from a cast) or prolonged sitting such as in an employment setting
    • Long plane, car, or train rides
    • Neurologic disorders with paralysis
    • CHF
    • Obesity
  • Vascular concerns/damage:
    • Trauma
    • Surgery, particularly orthopedic surgeries
    • Intravenous drug abuse
    • Dialysis
    • Anatomic anomalies (May–Thurner syndrome, congenital heart disease, Paget–Schroetter)
    • Central lines/pacemaker placement:
      • Especially upper-extremity DVT
  • Multifactorial issues:
    • Advancing age
    • Comorbid conditions (diabetes, hypercholesterolemia, hypertension)
    • Other medications (hydralazine, procainamide, phenothiazines, tamoxifen, glucocorticoids, bevacizumab, some antidepressants)
    • Tobacco use
    • Prior DVT or PE
  • Genetics:
    • Family history of DVT/PE is an independent risk factor; ask about family history of clotting
    • There is no consensus about which patients with VTE to test for inherited thrombophilias

Pregnancy Considerations
Pregnancy is a risk factor for DVT up to 6 wk postpartum. Often affects left side preferentially due to anatomy and may involve pelvic veins. Treatment choices are more limited in pregnancy


Geriatric Considerations
Age in and of itself is a risk for DVT (and PE). As with many diseases, the presentation may be atypical in the elderly. Treatment considerations more complicated due to comorbid conditions, fall risk, etc.

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