Edema - Causes and Symptoms

Definition

Edema is an accumulation of fluid of varying consistency (soft, elastic or hard) in the intercellular spaces and in the interstices of the tissues, which is manifested by swelling and a feeling of tension or fullness. Other symptoms are usually associated with the underlying pathology.

At the origin of edema there are complex mechanisms, such as increased permeability of capillaries, retention of sodium chloride in tissues and insufficient drainage through lymphatic vessels.

Edema can suddenly appear or develop slowly and progressively, anywhere in the body, including the brain. The digital compression of the edematous part leaves an imprint (sign of the fovea) for some time.

Edema can derive from a generalized or local process (ie limited to a specific district of the organism).

Generalized edema

Generalized edema is most commonly caused by heart failure, liver failure and kidney disease, such as the nephrotic syndrome . This last condition derives from a damage of the glomeruli and is manifested by a diffuse uniform edema, ascites, swelling of the legs and marked skin pallor. Furthermore, in the nephrotic syndrome, the urine is foamy due to a remarkable proteinuria and the laboratory tests can show an alteration of the protein profile (reduction of albumins, increase in globulins etc.) and hyperlipidemia.

Heart failure edema typically worsens in the evening and tends to disappear with rest; this symptom may be associated with arterial hypertension, nocturia, hepatomegaly, dyspnea on exertion and paroxysmal nocturnal, pulmonary cracklings, turgor of the jugular veins and orthopnea. Typically, edema from heart failure is most evident at the ankles if the patient walks and in the sacral region, when the patient is ill in bed.

The generalized edema associated with a marked weight loss, muscular atrophy and alteration of the tropism of skin and cutaneous appendages can also occur due to malabsorption . In this case, the accumulation of liquids is the consequence of the altered absorption capacity of the intestinal mucosa. The causes of malabsorption can be genetic (eg celiac disease), acquired (eg pancreatic insufficiency, liver disease, bile diseases and dysenteric syndromes) or iatrogenic. Concomitant symptoms of malabsorption syndromes may include diarrhea, steatorrhea (fatty stools), anemia, asthenia and bone changes.

A generalized edema due to water retention, due to hormonal alterations, however, is present in the premenstrual syndrome . This is manifested by a set of disorders (such as breast tenderness, irritability, insomnia and abdominal bloating) that occur cyclically in the days preceding the menstrual flow.

Generalized edema can be induced by the use of some drugs, including non-steroidal anti-inflammatory drugs, estrogen and calcium channel blockers. In some cases, instead, it derives from an extrinsic venous compression (from a tumor, a pregnant uterus or marked abdominal obesity).

Other possible causes include chronic venous insufficiency, dysfunction of the lymphatic channels (lymphedema), prolonged enticement and excessive consumption of salty foods.

Localized edema

Localized edema is the consequence of venous or lymphatic stasis or derives from an allergic, inflammatory or infectious process . This manifestation most often affects the lower limbs - ankles, feet and legs - but it can also affect the face and hands.

The allergic skin form is manifested by pink-reddish swelling associated with dry skin, itching and burning due to massive release of histamine and vasoactive substance. Insect bites and animal contact or bite (eg spider fish, jellyfish and snakes) cause specific signs.

The edema localized by inflammation is circumscribed and not very elastic; moreover, it causes pain spontaneously and palpation, redness, heat and swelling (symptoms of inflammation).

When it is of traumatic origin, instead, the edema can be associated with signs of bruise, distortion and fracture.

In venous stasis, the accumulation of fluid is soft and localized distally at the level of the legs, ankles and feet. Generally, this condition is also associated with a feeling of heaviness in the lower limbs with dilation and tortuous course of the veins (varicose veins), accentuated by heat. In phlebitis, the skin is red and hot, with the possible presence of a venous cord painful at pressure.

Localized lymphatic edema, on the other hand, is initially soft, without fovea, and can be associated with signs of lymphangitis, with reddened and swollen regional lymph nodes, in the absence of varicose veins and skin ulcers.

Other causes of edema are soft tissue infections (eg cellulitis, necrotizing myofascitis, etc.), lymphatic filariasis and sepsis.

Edema can also be iatrogenic in nature, as happens, for example, after the removal of lymph nodes in oncological surgery or radiotherapy.