(Before on the left and after on the right)
An edema is the excretion of fluids from the vascular system and their accumulation in the interstitial space. In clinical practice edema usually means fluids inside the subcutis or a specified organ (for example lung edema). Edema can have organ specific causes (disorders of the cardiocascular system, of the kidneys, of the gastrointestinal tract) but is also dependent on hormones, medicines, and nutrition.