Posted 9/23/2016 4:42 PM (GMT -7)
there can be a number of reasons for edema to occur; edema is is symptom of imbalance in fluid management in the body. Understanding fluid dynamics in our tissues might help you think about how to manage it (forgive me if you already know this).
Arteries deliver oxygen-rich blood and nutrients to all body tissues and veins return blood from tissues to the heart for re-loading. The vessels get smaller and smaller as they make their way to tissues, turning into capillary beds in tissues, before they get bigger and become veins going back to the heart. Capillaries are designed to be leaky so water, ions, and nutrients like glucose and amino acids easily pass from the capillary bed into the interstitial space (the IS, it is the space between blood vessels and cells of other tissues/organs). Proteins and cells are retained in the capillaries under normal conditions. The only things driving water/ions/nutrients between IS and caps are pressure gradients and the concentration gradient of proteins in blood and IS. There is more hydrostatic pressure in the arterial-end of capillary bed than in the IS (about 10 mm Hg of pressure towards IS), so some water, etc is moved into the IS, feeding the tissues with nutrients (oxygen and CO2 simply diffuse across cell membranes here). At the venous side of the cap bed, the pressure is -8 mm Hg for two main reasons: veins are less muscular than arteries, so they cannot compress like arteries to maintain hydrostatic pressure. Also, all those proteins in retained in the blood provide "oncotic" pressure, which is attractive to water. So water leaves capillary beds on artery side, bringing with it nutrients and any other small molecules, water and cell waste products are reabsorbed at the venous end and returned to circulation. Note however not all fluid returns to the veins, that which does not is drained into the lymphatic system, through nodes and eventually into the thoracic duct which dumps lymph into the heart.
There are a number of ways in which imbalance of this fluid dynamic can result in edema, I will list ones more obvious ones
(1) A known SE of taxotere affects capillaries, making them more leaky- proteins leaks out as well, more fluid moves into IS and it is harder to recover water at venous end (less protein to pull it back in)- fluid accumulates; I tend to get this a week or so after chemo (big time on one cycle); exercise if possible (muscle activity helps drive blood back to the heart, pulling water out of IS), keep legs elevated for sure; lasix should help as it makes the kidneys dump more water as well. I talked a bit about this on the TAXOTERE SIDE EFFECTS thread a few weeks ago.
(2) a blood clot in a vein, called a deep vein thrombosis (DVT) will cause fluid backup and higher hydrostatic back pressure on the venous side-> fluid accumulation in IS. Usually this would only affect one limb (wherever the clot happened). The fact one leg is more swollen (and grossly so by your description) is something that could happen in a DVT- some possible symptoms of DVT, besides swelling, are redness or a warm spot or pain in the affected limb. Note that both my legs are pretty warm when general bilateral edema sets in due to chemo. It is important to rule out a new blood clot, since that can break off pieces of clot that can get into brain (stroke) or heart (cardiac arrest). I would want my relative to call the doctor NOW and describe this symptom and failure of lasix to control it.
(3) liver failure/malnutrition: liver makes most of the protein circulating in the blood, so failure drops protein content; if you are undernourished, there will be less protein in blood- in either case, there is less "pull" of water by proteins into venous side of cap bed -> fluid accumulation in IS
(4) heart failure (when heart is not pumping with enough force to serve tissue needs): this will, at first drop blood pressure (pump has less force, less pressure, right?) but our marvelous bodies sense this BP drop and constrict peripheral arteries to bring the BP back up- paradoxically, people with heart fialure can develop high BP due to this action- this increases hydrostatic pressure at artery side of cap beds, driving more fluid into IS; heart failure has been listed as a very rare SE of taxotere I believe.
(5) occlusion in the lymphatic system (caused by cancer, surgery, obesity) can block lymph drainage
many other things can cause edema (standing all day at work for sure)
But do call the doc. keep your legs up that will help blood return. do not exercise at this time, because if it is a clot in that bigger leg, well you do not want to do anything to break a piece off
good luck and here's to fightin' dude- I have so much respect for you-