The main reason for tissue edema when plasma protein is reduced is that the plasma colloid osmotic pressure is reduced in the capillaries, and fluid enters the tissue interstitium from the capillaries, causing tissue edema. 1. Under normal circumstances the fluid in the blood vessels and the tissue fluid in the surrounding tissues will remain in balance. When plasma protein decreases in the body, plasma colloid osmotic pressure decreases, fluid permeates from the blood vessels to the outside of the blood vessels, the balance between the inside and outside of the blood vessels breaks down, and more fluid accumulates in the body in the small cavities around the tissues and organs, thus causing tissue edema. 2. Tissue edema mostly starts from the feet and gradually spreads to the whole body. In severe cases, the backs of the hands and upper arms may have obvious depressed edema, and even the eyelids of the face may be swollen so that the eyes cannot be opened. If you find edema in your body, you should actively seek medical treatment to avoid delaying your condition.