edema

Edema refers to the accumulation of excessive fluid in the interstitial spaces outside the blood vessels, and is one of the common clinical symptoms. Edema manifests as obvious pitting when pressing with a finger on areas with less subcutaneous tissue (such as the anterior aspect of the lower leg). In traditional Chinese medicine, it is called "water qi." Traditional Chinese medicine defines edema as a condition in which various causes lead to impaired fluid metabolism in the body, with water-dampness retention and spreading over the skin, causing swelling of the head, face, limbs, or even the whole body. Edema is a common pathological process, and the accumulated fluid originates from plasma, with a sodium-to-water ratio roughly similar to that of plasma. Conventionally, the accumulation of excessive fluid in body cavities is called hydrops or effusion, such as pleural effusion, ascites, and pericardial effusion. Edema is a manifestation of systemic qi transformation dysfunction and is closely related to the lung, spleen, kidney, and Sanjiao (triple energizer) organs. Due to invasion by external pathogens, dietary irregularities, or excessive fatigue, the lung loses its function of dispersing and descending and regulating water passages, the spleen loses its function of transportation and transformation, the kidney loses its function of opening and closing, and the bladder's qi transformation becomes abnormal, leading to fluid retention in the body and spreading over the skin, with clinical features of swelling of the head, face, eyelids, limbs, abdomen, back, or even the whole body. According to different symptom manifestations, it is divided into two types: yang edema and yin edema, commonly seen in diseases such as nephritis, cor pulmonale, liver cirrhosis, nutritional disorders, and endocrine disorders.