Deep Vein Thrombosis (DVT) ✅

Related Subjects: | Assessing Breathlessness | Respiratory Failure | Pulmonary Embolism | Deep Vein Thrombosis | DVT/PE in Pregnancy | CTPA

🦵 Initial Deep Vein Thrombosis (DVT) Assessment & Management

🧠 About Deep Vein Thrombosis

• Most pulmonary emboli (PE) originate from pelvic or leg DVT.
• Untreated DVT may lead to pulmonary embolism 🫁 or post-thrombotic syndrome.
• Post-thrombotic syndrome occurs in up to 20–50% of patients and results from venous valve damage causing chronic venous hypertension.
• Pathophysiology follows Virchow’s Triad:
• 🩸 Hypercoagulability
• 🛌 Venous stasis
• 🧱 Endothelial injury

⚠️ Risk Factors

• 🛌 Immobility (stroke, illness, neurological disease)
• 🔪 Surgery (orthopaedic, pelvic, major abdominal)
• 🎗️ Malignancy
• 🤰 Pregnancy and postpartum
• 💊 Combined oral contraceptive pill (COCP)
• 🧬 Inherited thrombophilia (Factor V Leiden, Protein C/S deficiency)
• 👵 Age >60
• ⚖️ Obesity
• 🚬 Smoking
• ✈️ Long travel (>4 hours)
• ❤️ Heart failure

💊 COCP & VTE Risk

• ❌ No hormonal contraception: ~5 per 100,000 women per year
• 💊 Second-generation pill: ~15 per 100,000
• 💊 Third-generation pill: ~25 per 100,000
• 🤰 Pregnancy: ~60 per 100,000

🩺 Clinical Presentation

• Unilateral calf or leg swelling
• Calf pain or tenderness
• Warmth and erythema
• Dilated superficial veins
• Pitting oedema of affected limb
• Calf circumference increase >3 cm

⚠️ Classical signs such as Homan’s sign have poor sensitivity and specificity and are not recommended for diagnosis.

🔍 Investigations

• 🧪 D-dimer (use when Wells score ≤1)
• 🩻 Compression duplex ultrasound – first-line imaging
• 🧵 Contrast venography – historical gold standard (rarely used)
• 🧲 MRI/CT venography in selected cases (e.g. pelvic DVT)
• 🧬 Thrombophilia testing – only in selected patients

⚠️ Complications

• 🫁 Pulmonary embolism
• 🦵 Post-thrombotic syndrome
• 🔁 Recurrent venous thromboembolism

🔄 Differential Diagnoses

• Calf haematoma
• Ruptured Baker’s cyst
• Cellulitis
• Lymphoedema
• Chronic venous insufficiency
• Gastrocnemius muscle tear

💊 Management Overview

• Most patients suitable for ambulatory outpatient management.
• Early anticoagulation reduces risk of PE dramatically.
• Encourage mobilisation and hydration.
• Graduated compression stockings may help symptoms in some patients.

🎓 Exam Tips – Deep Vein Thrombosis

• Two-level Wells score is used in NICE guidance
  • ≤1 → DVT unlikely
  • ≥2 → DVT likely
  Older textbooks sometimes show a three-tier system (low/moderate/high).
• D-dimer should only be used when clinical probability is low. A positive result does not diagnose DVT because it is elevated in infection, malignancy, surgery, pregnancy, and inflammatory states.
• Compression duplex ultrasound is the first-line imaging test for suspected DVT in most patients.
• If imaging cannot be performed within 4 hours, NICE recommends starting interim anticoagulation and arranging ultrasound within 24 hours.
• Direct oral anticoagulants (DOACs) such as apixaban or rivaroxaban are now first-line treatment for most patients with confirmed DVT.
• Pregnancy management differs:
  • Use LMWH throughout pregnancy
  • Warfarin and DOACs are contraindicated
• Provoked DVT (e.g. surgery, trauma) → anticoagulation for 3 months.
• Unprovoked DVT → treat for ≥3 months then reassess bleeding risk before deciding on extended therapy.
• Most pulmonary emboli originate from proximal DVT (popliteal or femoral veins).
• Classic signs such as Homan’s sign are unreliable and should not be used to diagnose DVT.
• Always consider the possibility of occult malignancy in patients with unprovoked venous thromboembolism, particularly in older adults.

📚 References

• Venous thromboembolic diseases: diagnosis, management and thrombophilia testing (NG158) .
• Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism. Published by the European Heart Journal. 2020;41(4):543–603.
• Kearon C, Akl EA, Ornelas J, et al. Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report. Published by the Chest. 2016;149(2):315–352.
• Wells PS, Anderson DR, Bormanis J, et al. Value of assessment of pretest probability of deep-vein thrombosis in clinical management. The Lancet. 1997;350(9094):1795–1798. Development of the Wells clinical prediction rule by National Clinical Guideline Centre. Venous thromboembolic diseases: diagnosis and management. Commissioned by the :contentReference[oaicite:4]{index=4}.