Types of edema (according to their main causes and symptoms)

A disease suffered mainly by elderly people. We explain its signs.

It is common to hear elderly people with circulation problems say that they have fluid retention in their legs. If observed, they appear swollen and inflamed, as if they were partly filled with water.

The same happens sometimes after a burn, after a surgical intervention, if we suffer from liver, heart or metabolic disease or simply after standing for long periods of time and exercising in high temperatures.

This swelling is called edema, and it can have different types of origins. There are several types of edema, the main ones of which we will explore in this article.

What is edema?

By edema we mean the swelling of soft tissues caused by the presence of fluid accumulation in them.. Also known as fluid retention, this swelling can appear due to a great variety of causes, from the existence of a metabolic, hepatic or cardiovascular problem to being at an excessive temperature, making great efforts or too much time standing or sitting, the consumption of medications or the absence or excess of nutrients. It must be taken into account that although it can appear for innocuous causes, it can be a sign that may be indicating the presence of a disorder or disease.

The symptoms will vary according to the cause, although it is common to find fatigue, discomfort or tingling, difficulty of movement and reduction in the amount of urine emitted (which is why in many cases the associated treatment causes a dramatic increase in the urge to urinate).

Causes

What causes swelling is an imbalance in the interstitial fluid.. This is the fluid that bathes the space between the cells of our body and allows the cells to receive nutrients while eliminating waste. This fluid constantly flows in and out of our cells, maintaining a balance between the amount of fluid in and out of the cells. Occasionally, imbalances can occur that cause an accumulation of interstitial fluid in the white tissues, resulting in edema.

Edema can be grouped and classified according to various criteria. The most common ones refer to the level of generalization of the edema and the location of its origin or etiology.

Types of edema according to level of generalization

One of the ways of classifying edema is according to whether the fluid retention is generalized throughout the body or localized in a specific area. Two basic typologies can be considered in this regard.

1. Localized or local edema

This is the most common type of edema and the easiest to see. In them the presence of liquid is localized in certain points of the body, which are usually affected by some type of venous or lymphatic problem, such as a thrombus.

Some of the most common subtypes of local edema are the following.

1.1. Peripheral edema

This is the type of edema that is localized in the extremities.. They can have different causes, such as circulatory problems.

1.2. Cerebral edema

Edema in the brain can be very dangerous, as it can cause drowning or compression of neural tissue.. The effects may vary greatly, but dizziness, headache, memory and concentration problems and nausea are not uncommon, and may even lead to death in some cases.

Pulmonary edema

A dangerous as well as relatively frequent type of edemaThese types of edema cause the lungs of those who suffer from them to become waterlogged and often cause symptoms such as weakness, fatigue or choking sensations. It often appears in response to blood supply problems.

Macular edema

Occurs in or around the eye, it may be more or less severe depending on where it appears and whether it causes pressure on the eyeball..

1.5. Angioedema

Edema of the mucous membranes and skin.. It is usually caused by allergic reactions.

2. Generalized edema

This type of edema is rarer to see and usually has a cause that affects the whole body. Swelling occurs in a generalized manner. Within this group we can find different subtypes, which indicate where the cause of the swelling comes from.

2.1. Cardiac edema

This type of edema is the one that occurs in the heart.It presents a high danger if it is not treated because it can cause death. It is common for blood volume to decrease, venous pressure to rise and heart rate problems such as tachycardia or bradycardia to occur.

2.2. Deficiency edema

This type of edema is produced by the absence of nutrients due to malnutritionThis type of edema is caused by the absence of nutrients due to malnutrition, poor metabolism or by the emission or excessive expulsion of components from the body. For example, by anemia or by the emission in the urine of an excess of minerals.

2.3. Renal edema

Caused by difficulties in the filtration of blood and the expulsion of urine.. It is frequent that it produces in the known as acute nephritic syndrome, in which in addition usually appears a dark urine due to the presence of blood in it.

2.4. Cirrhotic edema

This type of edema is mainly due to problems derived from the liver.. The swelling and accumulation occur in the peritoneum. Sometimes it is accompanied by jaundice.

2.5. Idiopathic edema

This edema is linked to the presence of hormonal problems.

Types of edema according to their origin

In addition to its level of generalization in the organism, other types of edema can also be observed, for example if the affectation is produced by lymphatic alterations or by the presence of vascular alterations or alterations in Blood Pressure or composition.

3. Lymphatic edema

These are considered as such those types of edemas produced by causes and alterations linked to the lymphatic system.. Within them we can find the primary ones, in which there are birth malformations in the lymphatic system and that usually affect the extremities, or secondary ones in those cases in which there is an acquired damage in them.

The latter can be the effect of surgeries such as those to resect tumors in the lymphatic system, or in cases of burns, blows or infections that cause the destruction or hypofunctioning of a vessel.

4. Dynamic edema

This group of edemas includes those edemas in which the lymphatic system does not present alterations but in which an excess of liquid is perceived. caused by systems or situations in which the limbic system is not directly involved.

These include venous edemas derived from thrombi or problems in the blood vessels, those produced by blows that generate inflammation, medicinal edemas, gestational edemas in which the mother may experience swelling due to varicose veins and hormones during pregnancy, postpartum edemas, edemas produced by surgery (in which the lymphatic system itself is not altered), deficiency edemas or some of the general edemas.

Bibliographic references:

• Cecil, R. (2015). Cecil medicine (24th ed.). Philadelphia, Philadelphia: Saunders Elsevier.
• Kasper, D. (2015). Harrison's principles of internal medicine (19th ed.). New York, New York: McGraw-Hill, Medical Pub. Division.
• Renkin, E.M. (1994) Cellular aspects of transvascular exchange: a 40-year perspective. Microcirculation 1(3):157-67.