Venous Lymphedema

In the article, "Diagnosis and Treatment of Venous Lymphedema", Raju et al describe the phenomena of primary and secondary lymphedema.

http://www.jvascsurg.org/article/S0741-5214(11)01833-7/pdf

Primary lymphedema is congenital and is present from birth.  Secondary lymphedema occurs from damage and overload of the lymphatic system.  It is a concomitant symptom that sometimes occurs (20% to 30%) during later stages of CVD.  The occurrence is mostly likely much higher since secondary lymphedema is not always correctly identified and diagnosed.

As chronic venous disease (CVD) progresses to later stages, symptoms of lymphedema begin to emerge. These symptoms are referred to as secondary lymphedema or phlebolymphedema.

The article describes methods for the practitioner to use to distinguish between venous and lymphatic complications.

When a patient has leg swelling it is important to understand the origin of the swelling because it affects how the symptoms are treated.  The article gives the example of a patient who was diagnosed on clinical grounds as having primary lymphedema and was treated for several decades with compression, however the swelling in her legs did not subside (see Fig. 1 left below, ref article Fig 1.).  It was not until venography was done that it was realized that the complication was due to a stenosis in the iliac vein.  A stent was used to correct the stenosis.

The author highly recommends that the best way to diagnose the origin of a swollen leg is to use IVUS (intra-vascular ultrasound).  IVUS is a technique where a catheter with a transducer on the end is navigated through the venous vasculature and measures the ultrasound of the vein interior giving information about the venous perimeter, structure of the walls and whether there is a narrowing or occlusion.  IVUS is much like standard ultrasound in that it is an imaging technique.

The author makes an important point that IVUS is much preferred over venography when diagnosing the origin of swollen legs.  The reason is because venography can be misleading depending on the angle or viewpoint that the image is taken.  In venography contrast dye is injected into the vein and imaged.  As shown in Fig 3 below left (from ref article Fig 3) the vein looks normal.  However, the IVUS shown on the right indicates a stenosis.  The reason the venograph did not show the stenosis is because if the stenosis makes an ellipse and the image is taken along the long axis the vein will appear normal.

**The author strongly suggests that before diagnosing a patient as having primary lymphedema and referring patients for conservative therapy, IVUS should be routinely used to rule out the possibility of a venous complication.**