How is lymphedema diagnosed?

Diagnostic Approach for Lymphedema

The diagnosis of lymphedema requires a systematic approach including patient history, physical examination, and confirmatory diagnostic testing, with referral to a lymphedema specialist when clinical symptoms or swelling are present. 1, 2

Clinical Assessment

• Patient history should identify risk factors such as prior cancer treatment (especially lymph node dissection), radiation therapy, trauma, infection, or congenital abnormalities 2
• Self-reported symptoms including swelling, heaviness, and numbness should be thoroughly investigated to facilitate early diagnosis 2, 1
• For breast cancer survivors, assess for symptoms in the arm, breast, or chest on the affected side 1
• Evaluate for risk factors such as obesity, which is associated with increased lymphedema risk 1

Physical Examination

• Palpate the affected area for fibrosis, pitting, and overall tissue quality 1, 2
• Perform the Stemmer sign test: inability to lift the skin fold at the base of the second toe or finger compared to the contralateral limb indicates lymphedema 1, 2
• Note that obesity may cause a false-positive Stemmer sign 1
• Distinguish lymphedema from other causes of edema by evaluating for unilaterality and lack of response to elevation or diuretics 2, 3
• The Kaposi-Stemmer sign has the highest predictive value among clinical signs for lymphedema diagnosis 4

Diagnostic Measurements

• Circumferential measurement is the standard method for diagnosing upper extremity lymphedema (Stage 1 or greater) 1, 2
• Water displacement can diagnose lymphedema with volumetry >200 mL compared to the contralateral limb or with volumes >10% interlimb difference 1, 2
• Bioimpedance analysis (BIA) should be used to detect lymphatic transport impairments and diagnose subclinical and early-stage lymphedema (Stage 0 and 1) 1, 2
• L-Dex score of >7.1 should be used as diagnostic criteria for breast cancer-related lymphedema when no preoperative assessment is available 1
• If preoperative measures are available, a 5% or greater volume change from baseline above and below the elbow is diagnostic of upper extremity lymphedema 2

Advanced Imaging

• Lymphoscintigraphy is considered the gold standard objective test for confirming lymphedema diagnosis with 95% accuracy 4, 5
• Patients with a negative Stemmer sign but high clinical suspicion for lymphedema warrant referral for lymphoscintigraphy 1
• Ultrasound should be used as a diagnostic tool to identify tissue changes and can augment the diagnostic process 1, 6
• MRI and CT may be used as diagnostic tools in complex cases 1, 2
• Lymphography may be used to detect lymphatic system impairment in specialized settings 2, 3

Diagnostic Questionnaires

• Validated questionnaires that assist in the diagnosis of secondary upper quadrant lymphedema include the Norman Questionnaire and Morbidity Screening Tool 1, 2

Staging and Referral

• The International Society of Lymphology provides a staging system to categorize the extent of lymphedema 1
• Patients with clinical symptoms or swelling suggestive of lymphedema should be referred to a therapist knowledgeable about lymphedema diagnosis and treatment, such as a physical therapist, occupational therapist, or lymphedema specialist 1, 2
• For breast cancer survivors, referral to a vascular specialist/clinic is recommended if lymphedema is present 2

Common Pitfalls and Caveats

• Clinical signs alone are unreliable for lymphedema diagnosis, with studies showing they may be inaccurate in up to one-third of patients 4
• Among patients with lymphoscintigraphy-confirmed lymphedema, only 17% had positive clinical signs, indicating the need for objective testing 4
• Venous obstruction is the most common cause of clinical signs in patients without true lymphedema 4
• In moderate to late-stage lymphedema with fibrosis and tissue changes, BIA measurements may show decreasing extracellular fluid even with increased tissue volume 1, 2
• Perometry may be used for assessment of volume but not as a diagnostic tool 1
• Patients with lymphedema are at increased risk for cellulitis, which can exacerbate the condition 1