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.

Additional related clinical topics

Subclavian Vein Thrombosis (SCVT)

🩺 The subclavian vein lies beneath the clavicle and continues from the axillary vein, merging with the internal jugular vein to form the brachiocephalic vein. ⚠️ Thrombosis here (SCVT) is an important form of upper-extremity DVT.

📖 About

• 🩸 Subclavian vein thrombosis (SCVT) = upper-limb DVT.
• 🔗 Causes: trauma, catheters, malignancy, or inherited clotting disorders.

🧬 Aetiology (Virchow’s Triad)

• 🩸 Hypercoagulability (blood composition changes).
• 🌀 Stasis/turbulent flow.
• 🧱 Endothelial injury/damage to the vessel wall.

📌 Causes

• Primary SCVT 🏋️‍♂️ (Effort-Induced):
  • 💪 Paget–Schroetter Syndrome: Young, healthy, after vigorous activity.
  • ❓ Idiopathic: sometimes due to hidden malignancy.
• Secondary SCVT 🏥:
  • 🦴 Trauma (clavicle fracture, compression).
  • 💉 Central venous catheters, pacemakers, dialysis lines, TPN.
  • 🛏️ Prone positioning during surgery.
  • 🧬 Inherited thrombophilia (e.g., Factor V Leiden, Protein C/S deficiency).
  • 🎗️ Lung cancer (esp. Pancoast tumours).

🩺 Clinical Features

• 💪 Arm swelling, oedema, heaviness.
• 🌐 Dilated veins (neck, shoulder, arm).
• 🔵 Cyanosis in fingers/hand.
• 📈 Possible lymphadenopathy (cervical/axillary).
• 👩‍⚕️ Breast exam if malignancy suspected.

🧪 Investigations

• 🧾 Bloods: FBC, U&E, ESR/CRP, ↑ D-dimer.
• 🧬 Thrombophilia screen (esp. young pts).
• 🖼️ Imaging: CXR, CT/MRI venography.
• 🔊 Duplex ultrasound = first-line.
• 💉 Contrast venography = gold standard.
• 🎗️ Mammography if breast cancer suspected.

⚠️ Complications

• 🫁 Pulmonary embolism (PE).
• 🦵 Post-thrombotic syndrome (chronic swelling, stasis ulcers).
• 🦠 Septic thrombophlebitis.
• 🫀 Superior vena cava (SVC) syndrome.
• 🚫 Loss of central venous access (catheter occlusion).

🔍 Differential Diagnoses

• 🫀 Superior vena cava syndrome.
• 🧬 Lymphatic obstruction.
• 🔥 Cellulitis.
• 🪓 Thoracic outlet obstruction.
• 🎗️ Pancoast tumour.
• ☠️ Necrotizing fasciitis.
• 🩸 Superficial thrombophlebitis.

🛠️ Management (Cause-Dependent)

• 💉 Anticoagulation: Start LMWH → warfarin/DOACs.
• 🧼 Thrombolysis: Catheter-directed in effort-induced/catheter-related cases.
• 🪡 Stenting: For significant venous narrowing.
• 🕵️ Investigate: Underlying malignancy or thrombophilia.
• ❌ Remove catheter: If device is the culprit (after acute phase).

📚 References

• Subclavian Vein Thrombosis – StatPearls (NCBI)

🧑‍⚕️ Case Examples - Subclavian Vein Thrombosis (SCVT)

• Case 1 (Effort-induced / Paget-Schroetter syndrome): 🏋️ A 22-year-old competitive rower presents with sudden swelling, heaviness, and cyanosis of the right arm after intense training. Dilated superficial chest wall veins are visible. Analysis: “Effort thrombosis” of the subclavian vein due to repetitive overhead arm activity causing venous compression. Diagnosis: Duplex ultrasound confirms acute SCVT. Management: Anticoagulation, catheter-directed thrombolysis if severe, and later surgical decompression (first rib resection) to prevent recurrence.
• Case 2 (Catheter-related SCVT): 💉 A 65-year-old man with a central venous catheter for chemotherapy develops left arm swelling, pain, and erythema over 48 hours. Analysis: Indwelling catheters are the commonest cause of secondary SCVT, provoking local thrombosis. Diagnosis: Duplex/CT venography shows thrombus around catheter in the left subclavian vein. Management: Anticoagulation (LMWH/DOAC), remove catheter if no longer essential, oncology team review.
• Case 3 (Malignancy-associated SCVT): 🎗️ A 58-year-old woman with known breast cancer presents with right arm swelling, facial plethora, and dilated chest wall veins. Analysis: Cancer is a strong pro-thrombotic state; extension towards the SVC suggests SVC obstruction. Diagnosis: CT venography shows right subclavian vein thrombosis with proximal extension. Management: Anticoagulation, oncology input, consider stenting if symptomatic SVC obstruction.