Physical Examination Findings in Deep Vein Thrombosis (DVT)
Classic physical examination findings in DVT have poor sensitivity and specificity, with physical examination alone being only about 30% accurate for diagnosing DVT. 1 Therefore, objective testing is essential for confirming the diagnosis.
Key Physical Examination Findings
Classic Signs
- Unilateral leg swelling - Entire leg swelling is a key finding in the Wells score 2
- Calf swelling - Particularly when ≥3 cm larger than the asymptomatic side 2
- Localized tenderness along deep veins - Important component of the Wells score 2
- Pitting edema confined to the symptomatic leg 2
- Collateral superficial veins - Dilated superficial veins may develop as collateral circulation 2
Less Common Signs
- Pain or discomfort in the affected limb
- Warmth of the affected limb
- Erythema or skin discoloration
- Homan's sign (calf pain upon dorsiflexion of the foot) - historically described but has poor sensitivity and specificity 3
Limitations of Physical Examination
- Approximately one-third of patients with DVT do not have any symptoms 3
- Symptoms are often not apparent until there is involvement above the knee 3
- Clinical diagnosis using physical examination alone is unreliable, with only 30% accuracy 1
- Many conditions can mimic DVT clinically, including:
- Baker's cyst (intact or ruptured)
- Cellulitis
- Lymphedema
- Chronic venous disease
- Musculoskeletal disorders 3
Clinical Risk Assessment
The Wells score is recommended to stratify patients into probability categories:
| Factor | Points |
|---|---|
| Active cancer | 1 |
| Paralysis, paresis, or recent immobilization | 1 |
| Bedridden ≥3 days or major surgery within 12 weeks | 1 |
| Localized tenderness along deep veins | 1 |
| Entire leg swollen | 1 |
| Calf swelling ≥3 cm larger than asymptomatic side | 1 |
| Pitting edema confined to symptomatic leg | 1 |
| Collateral superficial veins | 1 |
| Previous DVT | 1 |
| Alternative diagnosis at least as likely | -2 |
- Score ≥2: High pretest probability
- Score <2: Low/moderate pretest probability 2
Diagnostic Algorithm
- Assess clinical probability using Wells score
- Measure D-dimer (particularly useful in patients with low/moderate pretest probability)
- Perform compression ultrasonography:
- If positive, treat for DVT
- If negative but high clinical suspicion remains, consider:
- Repeat ultrasound in 5-7 days
- CT venography or MR venography 2
Anatomical Considerations
Physical findings may vary based on the location of the thrombosis:
- Proximal DVT (above knee): More likely to present with obvious swelling and other classic signs
- Distal DVT (below knee): Often has subtle or absent physical findings
- Iliac vein thrombosis: May present with entire leg swelling but can be missed on standard proximal compression ultrasound 2
Pitfalls in Physical Examination
- Relying solely on clinical examination is not recommended due to poor sensitivity and specificity 2
- Failing to consider isolated iliac vein thrombosis when standard physical examination is equivocal 2
- Missing distal DVT due to subtle physical findings 2
- Overlooking non-vascular causes of unilateral leg swelling 2
- Delaying appropriate diagnostic testing in patients with suspicious findings 2
Physical examination findings should always be interpreted in conjunction with clinical risk factors, D-dimer testing, and appropriate imaging studies to accurately diagnose or exclude DVT.