Learning to diagnose lymphedema properly can be challenging, as many training programs lack knowledge and exposure to lymphedema patients. Unfortunately, there is no single standard official diagnostic criteria for determining if someone has lymphedema. This becomes even more complicated for patients with primary lymphedema, where the symptoms may have been present since birth or have been around for years and gradually worsened.
There are some diagnostic or imaging tests that can be performed to help with diagnosis, however, a physical exam and thorough history of symptoms are typically the key parts of diagnosis and most experts use history and physical examination alone to make the diagnosis.
Imaging technologies such MRI, CT, or ultrasounds can be used to see if there is a collection of extracellular fluid in the tissue. Bio-impedance spectroscopy looks at how the tissue conducts a small, imperceptible electrical current and can also be used to detect extracellular fluid. Bio-impedence can also be used to detect patients in Stage 0 Subclinical phase, when their physical exam will be unremarkable. Lymphoscintigraphy is a type of imaging done at some centers that uses nuclear medicine to see lymph vessels and lymph nodes. It can show if your lymphatic system has any abnormalities in lymph flow or structure.
What factors should be considered to help diagnose a patient with lymphedema?
Diagnosis of Lymphedema
- History and physical exam
- Soft Tissue Imaging (MRI, CT and some types of ultrasound)
- Lymphatic Imaging (Lymphoscintigraphy)
- Limb volume measurements
- Bioimpedance testing
- Biomechanical property (tonometry, tissue bioelectric constant)
- Genetic testing
What is the most common finding on physical exam that is diagnostic of lymphedema?
Most experts rely on a good history and physical exam to diagnosis lymphedema. Of all the clinical findings, many experts rely heavily on use of the Kaposi-Stemmer’s sign. This test measures the ability of a clinician to lift and tent tissue. A positive Stemmer’s sign is diagnostic of lymphedema. It is classically measured at the base of the toes in the foot for patients with lower extremity swelling. It can be measured anywhere in the body where lymphedema is suspected. If you can gently pinch and can tent the tissue (bring the skin folds together), then the Stemmer’s sign is negative. If you cannot gently pinch and tent the tissue, this is because the protein rich lymph fluid in the tissues prevents you from bringing the skin folds together and the Stemmer's sign is positive. A positive Stemmer's sign is diagnostic of lymphedema. In Figure 1, notice that the clinician is not able to bring the skin folds together, so the Stemmer's sign is positive and this patient has a diagnosis of lymphedema.
If the Stemmer’s sign is negative, a patient can still have a diagnosis of lymphedema in that limb. If the Stemmer’s sign is positive, the patient has diagnosis of lymphedema. Clinicians also often discuss doughy pitting but this is nonspecific and depending on the consistency is seen in both edema and lymphedema conditions. See Fig. 2 below to see example of a patient with soft deep pitting edema. This could represent edema or lymphedema, but the patient also has swelling of the toes. In this case, the patient’s history will reveal a diagnosis of phlebolymphedema (chronic CVD with development of secondary lymphedema).
Other Ways Lymphedema is Diagnosed
Limb measurements have been a standard way of diagnosing lymphedema for decades and have been shown to be accurate1. The International Society of Lymphedema has a simple limb volume assessment scale to determine severity and help with staging.
- Mild: < 20% limb increase
- Moderate: 20-40% increase
- Severe: > 40% increase
Other factors considered are extensiveness of swelling, presence of infections, inflammation, and other descriptors.
For breast cancer related edema and patients followed over time, the National Lymphedema Network (NLN) recommends professional referral to a certified lymphedema therapist any time there is a >=2cm change in any of the circumferential measurements or a >5% volume change to the at risk limb. A minimum of six measurements per limb are recommended. Measurements should be done by a trained medical professional.
1. Position Statement of the National Lymphedema Network. Topic: The Diagnosis and Treatment of Lymphedema. Updated Feb. 2011.
2. The Diagnosis and Treatment of Peripheral Lymphedema: 2013 Consensus Document of the International Society of Lymphology. Lymphology 46 (2013) 1-11.