What is swelling?
Eyelids swollen after a night's sleep or feet that are swollen by the end of the working day are, perhaps, all that most people know about edema. But the above states are not their only manifestations.
Let's take a closer look at what edema is.
How are edemas formed?
Edema is an excessive accumulation of fluid, the so-called transudate, in tissues or in body cavities.
The body of an adult contains about 11 liters of tissue fluid, which is an important part of the internal environment of the body. The chemical composition of the tissue fluid is very similar to blood plasma, which is not surprising, because the intercellular tissue fluid is a derivative of plasma. Plasma (the liquid part of the blood) seeps through the walls of the capillaries into the extracellular space, then some of the tissue fluid enters the lymphatic vessels.
The lymph resulting from this process is filtered by the lymph nodes and drains back into the bloodstream.Thus, a constant interchange of substances occurs between the blood and the tissue fluid. In the event that this process of fluid circulation is disturbed for some reason, the fluid does not have time to return to the blood, it begins to accumulate in some parts of the body. It is there that edemas develop.
Forms and types of edema
Forms of swelling
- The most common form of edema is one in which tissue fluid accumulates in the subcutaneous tissue.
- Much less common are edemas of internal organs, such as pulmonary edema or swelling of the brain.
- In addition, the edematous fluid can accumulate not in the tissues, but in the internal cavities of the body. In this case, doctors diagnose hydrothorax (if transudate accumulates in the pleural cavity) or ascites (if fluid accumulates in the abdominal cavity).
In addition to the classification of the place of accumulation of edematous fluid, edema is divided into separate types depending on the factors that cause them.
Types of swelling
- Cardiac edema is a characteristic symptom of many heart diseases, accompanied by a state of chronic heart failure.First of all, cardiac edema affects the lower limbs - in case of heart disease, the feet and ankles swell a lot.
- Renal edema is a consequence of various kidney diseases, such as glomerulonephritis or pyelonephritis. Renal edema mainly occurs on the face, their characteristic location is the eyelids, especially the lower ones.
- Congestive edema are caused by venous congestion due to thrombophlebitis. They are located, as a rule, on the legs.
- Allergic edema occurs due to a perverse reaction of the immune system to an external irritant (allergen). Such swelling appears mainly on the face, especially on the lips and eyelids.