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Deep Vein Thrombophlebitis (DVT)

Basics

  • Blood clot formation in deep veins, usually post-surgery or trauma.
  • Associated vessel wall inflammation.
  • Major clinical risks: embolization (typically pulmonary embolism), recurrence, and postphlebitic syndrome.

Epidemiology

  • Hospital-associated venous thromboembolism (VTE) incidence 100x higher than community.
  • Nearly 50% of VTEs occur during or soon after hospitalization or surgery.
  • 10-30% mortality within 1 month of DVT/PE diagnosis.
  • 33% recurrence risk within 10 years.
  • 20% of VTE patients complicated by PE.
  • Incidence: 50.4 per 100,000 person-years (USA).
  • Most common site: lower extremity.
  • Pregnancy incidence: 0.5–3 per 1,000.
  • 1–5% of central venous catheters complicated by thrombosis.

Etiology & Pathophysiology

  • Virchow triad: venous stasis, endothelial injury, hypercoagulability.
  • Genetic thrombophilias:
  • Factor V Leiden (3-6x VTE risk).
  • Prothrombin G20210A mutation (~3x risk).
  • Other hereditary factors: Protein C, S, antithrombin III deficiencies, dysfibrinogenemia, hyperhomocysteinemia.

Risk Factors

  • Acquired:
  • COVID-19 infection (up to 3 months post-infection).
  • Previous DVT.
  • Cancer.
  • Immobilization.
  • Trauma/brain injury.
  • Recent major surgery.
  • Medications: OCPs, estrogens, tamoxifen, glucocorticoids.
  • Obesity, smoking.
  • Antiphospholipid syndrome.
  • Infection.
  • Pregnancy/puerperium.
  • Central venous catheters.
  • Inflammatory bowel disease.
  • Hereditary:
  • Protein C, S, antithrombin III deficiency.
  • Factor V Leiden R506Q.
  • Prothrombin G20210A mutation.
  • Elevated factor VIII.
  • Hyperhomocysteinemia.

Prevention

  • Mechanical thromboprophylaxis in high bleeding risk patients.
  • Pharmacologic prophylaxis with LMWH, low-dose unfractionated heparin, or fondaparinux in acutely/critically ill.

Diagnosis

History

  • Assess risk factors.
  • Classify DVT as provoked or idiopathic.
  • Evaluate bleeding risk before therapy.
  • Use Modified Wells Criteria to estimate pretest probability.

Modified Wells Criteria (DVT)

Criterion Points
Active cancer (treatment ongoing or within 6 mo) +1
Calf swelling >3 cm compared to asymptomatic leg +1
Collateral nonvaricose superficial veins +1
Pitting edema in symptomatic leg +1
Previous documented DVT +1
Swelling of entire leg +1
Localized tenderness along deep veins +1
Paralysis, paresis, or recent immobilization +1
Recently bedridden >3 days or surgery <4 weeks +1
Alternative diagnosis as likely or more likely -2
  • Interpretation:
  • 0 = DVT unlikely
  • 1–2 = Moderate risk
  • ≥3 = DVT likely

Physical Exam

  • Pain, swelling, tenderness, discoloration may be present or absent.
  • Edema due to collateral vein swelling is most specific.
  • Homan sign is unreliable.

Differential Diagnosis

  • Cellulitis
  • Fracture
  • Ruptured Baker cyst
  • Lymphedema
  • Calf muscle injury
  • Achilles tendon tear
  • Venous compression (tumor, lymphadenopathy)
  • Compartment syndrome
  • Allergic reaction

Diagnostic Tests

  • Routine labs (CBC, metabolic panel, coagulation) not diagnostic.
  • D-dimer:
  • Sensitive, not specific.
  • Useful in low/moderate pretest probability.
  • Adjusted cutoff for age >50: age × 10 ng/mL.
  • False positives: liver disease, inflammation, malignancy, trauma, pregnancy, surgery.
  • Compression Ultrasound (CUS):
  • First-line imaging.
  • Guided by pretest probability.
  • Other imaging (CT venography, MR venography) rarely used.
  • Thrombophilia testing for young/idiopathic/recurrent cases.

Treatment

Anticoagulation

  • Initiate before confirmation if high pretest probability and low bleeding risk.
  • Duration:
  • Minimum 3 months for proximal DVT/PE.
  • Extended or indefinite for unprovoked or recurrent events.
  • Direct Oral Anticoagulants (DOACs) preferred over warfarin in most cases without cancer.
  • First-line agents:
  • Unfractionated Heparin: IV infusion titrated to aPTT.
  • Low Molecular Weight Heparin (LMWH): enoxaparin, dalteparin.
  • Factor Xa inhibitors: fondaparinux, rivaroxaban, apixaban, edoxaban.
  • Direct thrombin inhibitor: dabigatran.
  • Warfarin: overlap with heparin until INR therapeutic (2-3).

Pregnancy Considerations

  • Warfarin contraindicated (teratogenic).
  • LMWH preferred.

Surgical/Procedural

  • Catheter-directed thrombolysis/thrombectomy in selected iliofemoral DVT.
  • IVC filter reserved for contraindications or recurrent embolism despite anticoagulation.

Admission Criteria

  • Respiratory distress
  • Elevated cardiac biomarkers/right ventricular dysfunction
  • History of heparin-induced thrombocytopenia (HIT)
  • Limb-threatening ischemia (phlegmasia)
  • Renal failure
  • Active bleeding

Ongoing Care

  • Limb elevation and compression stockings for symptomatic relief.
  • Routine compression stockings for PTS prevention not recommended.
  • Monitor platelet counts for HIT.
  • Evaluate for bleeding and underlying lesions if hemorrhage occurs.
  • Educate about diet/vitamin K intake with warfarin.

Prognosis

  • Untreated proximal DVT: 20% progress to PE; 10-20% PE fatal.
  • Anticoagulation reduces mortality 5- to 10-fold.
  • Up to 75% develop postthrombotic syndrome (PTS) in 5-10 years.

Complications

  • Pulmonary embolism (10-20% fatality)
  • Paradoxical arterial embolism
  • Chronic venous insufficiency
  • Postthrombotic syndrome
  • Hemorrhage from anticoagulation
  • Phlegmasia cerulea dolens (surgical emergency)

ICD10: - I80.209 Phlebitis and thrombophlebitis of unspecified deep vessels of lower extremity - I80.299 Phlebitis and thrombophlebitis of unspecified deep vessels of lower extremity - I80.10 Phlebitis and thrombophlebitis of unspecified femoral vein

Clinical Pearls: - Many VTE cases asymptomatic. - Up to 40% of DVT patients have asymptomatic PE. - Wells criteria useful for pretest probability but must be followed by appropriate imaging/testing. - Anticoagulant choice individualized to patient history, bleeding risk, cost, and compliance.