Can a non-circumferential second-degree burn increase the risk of Deep Vein Thrombosis (DVT)?

DVT Risk Assessment in Non-Circumferential Second-Degree Burns

Yes, obtain a duplex ultrasound to rule out DVT in this patient, as burn injuries create a prothrombotic state and the clinical presentation (pain radiating to groin with swelling) warrants investigation despite the burn being non-circumferential and second-degree. 1

Why Burns Increase DVT Risk

Burn patients meet all three components of Virchow's triad, making them inherently prothrombotic 2:

• Endothelial damage occurs from the thermal injury itself 2
• Hypercoagulability develops from the systemic inflammatory response 2
• Venous stasis results from immobility, pain-related reduced mobility, and local tissue swelling 1

Large hematomas and tissue injury can compress adjacent deep veins, causing venous stasis and reduced blood flow 1. The local inflammatory milieu from tissue injury and blood breakdown products creates a prothrombotic environment 1.

Clinical Presentation Supports DVT Evaluation

The patient's symptoms are concerning for DVT and cannot be dismissed as burn-related pain alone:

• Pain radiating up the leg into the groin is a classic DVT symptom pattern 3
• Associated swelling beyond the immediate burn area suggests venous obstruction 3
• Negative Homan's sign has poor sensitivity and should not be used to rule out DVT 3
• Clinical signs (pain, swelling, erythema, warmth) are unreliable in burned extremities, making objective testing essential 4, 5

Diagnostic Approach

Duplex ultrasound is the appropriate initial imaging modality 1, 3:

• Grayscale imaging directly visualizes echogenic thrombus and assesses vein compressibility 1
• Doppler evaluation identifies altered blood flow patterns and can detect central venous obstruction 1
• This is the standard first-line test recommended for suspected lower extremity DVT 3

Do not rely on D-dimer testing in burn patients:

• D-dimer has extremely poor specificity (only 20%) in burn patients 4
• 76-86% of burn patients have elevated D-dimer regardless of DVT presence 4
• The positive predictive value is only 5% in this population 4
• D-dimer is not a useful screening tool for DVT in burns, contrary to its value in general trauma patients 4

DVT Incidence in Burn Patients

The reported incidence varies widely in the literature:

• Large retrospective studies report VTE rates of 0.61-1.03% 2
• Prospective screening studies show much higher rates of 1-23% 5, 2
• The discrepancy reflects underdiagnosis when screening is not performed 5
• Even "low-risk" burns can develop DVT, particularly with lower extremity involvement 5

Risk Factors Present in This Case

This patient has several concerning features 5, 2:

• Lower extremity burn (medial left leg) - a specific high-risk factor 5
• Several days post-injury - mean time to DVT diagnosis is 6.7 days in burn patients 6
• New-onset symptoms suggesting possible thrombus formation 3
• Reduced mobility from pain (implied by presentation) 2

Management Algorithm

Immediate steps:

1. Order duplex ultrasound of the left lower extremity to evaluate for DVT 1, 3
2. If ultrasound is negative but clinical suspicion remains high, consider repeat ultrasound in 1 week 3
3. If DVT is confirmed, initiate anticoagulation per standard VTE treatment guidelines (minimum 3 months) 3

Thromboprophylaxis considerations going forward:

• If DVT is ruled out, consider initiating pharmacologic prophylaxis with low molecular weight heparin or unfractionated heparin 5000U subcutaneously every 8 hours 2
• Early pharmacological thromboprophylaxis should be initiated within 6-36 hours after trauma once bleeding is controlled 1
• For isolated lower limb injury without persistent bleeding, aim for initiation within 6 hours 1

Common Pitfalls to Avoid

• Do not dismiss leg pain as "just the burn" - this is how DVTs are missed in burn patients 4, 5
• Do not rely on physical examination findings alone - Homan's sign and popliteal tenderness have poor sensitivity 3
• Do not order D-dimer - it will likely be positive regardless of DVT presence and provides no useful information 4
• Do not assume non-circumferential or "small" burns are low-risk - DVT can occur with any burn involving the lower extremity 5