The loss of fluid from a leg is often the sign of an altered venous circulation complicated by superficial wounds (venous ulcers). At other times it may be a sign of heart, liver or kidney problems.
In the course of the article we will try to understand why the phenomenon occurs and what are the possible solutions.
To understand: Capillaries, Inflammation, Edema
exudate
The capillaries only transfer certain substances to the tissues - such as oxygen, water, glucose, lipids, etc. - present in the blood. In particular, only substances below a certain size are able to cross the capillary wall and reach the tissues; most of the proteins, for example, as well as the blood cells themselves, fail to cross that wall and remain inside the capillaries.
In the presence of a wound it is necessary that the proteins and the blood cells (in particular the white blood cells) reach the site of the lesion, in order to coordinate the reparative processes and avoid any infections. For this reason, in the presence of an inflammatory process (caused by a wound or other factors), capillary permeability increases; consequently, even greater quantities of liquid escape from the capillaries, which accumulate in the lesion constituting the so-called exudate . This is why wounds and other local inflammatory processes are often accompanied by swelling of the area, called edema .
The exudate can contain multiple substances, including water, electrolytes, nutrients, inflammation mediators, leukocytes, proteolytic enzymes (eg matrix metalloproteinases - MMPs), growth factors and waste materials.
exuding
Next to the blood capillaries we find the lymphatic capillaries. Their function is to reabsorb excess fluid from the blood capillaries, preventing it from accumulating in the tissues.
Under normal conditions, the lymphatic capillaries only absorb small amounts of the liquid that comes out of the blood capillaries. About 90% of this liquid is in fact reabsorbed by the same blood capillaries.
We must therefore strive to imagine capillaries as thin tubes, which
- in the initial part (arterial extremity) they give liquid (filtration)
- in the final part (venous extremity) they reabsorb it (reabsorption).
This mechanism is allowed by the different pressure gradients between capillary blood and interstitial fluids. When these pressures vary with respect to normality anomalies are registered in the filtration and reabsorption processes.
In particular, when the pressure at the venous end increases, the resorption loses its effectiveness, excessive amounts of liquids stagnate in the interstitial spaces and the tissue swells.
SKIN LESIONS
In the presence of skin lesions the leakage of oedematous liquids is favored and the loss of fluid from the leg can be significant.
Causes
For what was said in the previous chapter, the loss of fluid in the legs can be caused by:
- wounds and skin ulcers : the associated inflammation causes an accumulation of fluids in the exudate type area. The presence of these liquids tends to decrease with the healing process; vice versa, if the wound does not heal, due to the persistent inflammatory process the production of exudate can continue and become excessive.
Excessive accumulation of exudate in the wound hinders the healing process. Another important aspect to consider is that the quantities of exudate produced are higher in more superficial and extensive wounds; venous leg ulcers, burns, skin sampling sites and inflammatory ulcers are therefore more prone to produce high amounts of exudate.
- poor lymphatic circulation ( lymphatic stasis): the failure to reabsorb excess fluid that comes out of the capillaries, causes an accumulation of liquids in the area; situations of lymphatic stasis are recorded during some parasitic infestations and neoplasms that compress the large lymphatic trunks, or after their removal during surgical operations.
- bad venous circulation ( venous stasis, venous insufficiency, varicose veins ): if the veins cannot carry adequate quantities of blood to the heart - because it remains standing for a long time, because they are less effective due to aging, because they wear clothes narrow etc - the pressure at the venous ends of the capillaries increases; consequently the reabsorption of fluids from the tissues is less effective, an edema is created and the leg loses fluids. Of all, this is the most common cause of fluid leaks from the leg .
- kidney problems (kidney failure), liver problems (liver failure) or serious nutritional deficiencies : if there are few proteins in the blood (because the kidney lets them escape, because the liver does not produce them enough or for serious dietary deficiencies), the quantities of liquids escaping from the capillaries increase. Consequently an edema is created that, if of important dimensions, can drip. Compared to other causes, in these surrounding the edema is generalized, therefore it tends to appear in both legs and in other areas of the body, such as the abdominal area, which will appear edematous with or without drip.
- heart problems (right heart failure or heart failure) : if the right heart cannot completely empty the venous blood, there is an increase in venous pressure; therefore resorption is not very effective and edema is realized. Also in this case the edema is generalized and therefore tends to involve both the lower limbs and also the abdominal organs.
What to do
In the presence of fluid leaks from the leg the application of an elastocompressive bandage is indicated, to be changed frequently. Application by expert personnel is recommended.
The use of polyurethane foams under the compression bandage is indicated above all in chronic ulcers, since it allows to reduce the frequency of bandage changes and to accelerate healing.
The treatment of the underlying causes should be planned by a doctor after a careful diagnosis.
