Lymphoedema is a progressive condition. Having an understanding of how the Lymphatic System works is a great start to understanding how lymphoedema develops.
When lymph nodes are either removed or damaged as a result of surgery or injury a blockage occurs. Initially a drain is put in place around the wound site to drain off the lymph fluid and blood collecting in the site of the operation. When the flow of fluid slows down, the drain is usually removed, which means, the ends of the lymph vessels are closing up and scar tissue is forming. When this happens, the fluid is no longer able to flow through its normal path to lymph nodes. The blood circulatory system continues to deliver nutrients & fluid to site of the operation which can cause swelling around that site.
As the lymphatic system is a network of vessels travelling all over the body, the fluid trapped in the blocked lymph capillaries & the additional fluid being delivered by the blood circulatory system, has to be encouraged to either find another pathway or move out of the blocked lymph capillaries so that the fluid can be taken up by other lymph capillaries. This allows the lymph fluid to travel to a lymph node where it can be reabsorbed or eliminated from the body.
If the lymph vessels around the site of the blockage are not encouraged to move the lymph fluid builds up in those vessels and over time becomes thicker backing up the system, all the way down the lymph vessels path down a limb.
Once the lymph capillaries are full of lymph fluid the system essentially becomes blocked preventing more fluid entering the system. The interstitial fluid builds up and swelling begins to occur. Often the swelling goes undetected initially until the limb (leg/arm) or feet/ankles/hand swells up, even though you may have been experienced pain from the full, tight lymph vessels. Gravity also assists in the pooling of fluid in the interstitial space at the body’s extremities.
If lymph fluid is not moved around the blockage, along the lymph pathway and the interstitial space, patients with lymphedema develop progressive fibroadipose deposition (tough fibrous, fatty tissue) in the affected limb and have an increased risk of developing infections and secondary malignancies. These pathologic changes cause significant morbidity and decrease quality of life.