Increase in the quantity of fluid in the space between tissue cells, caused by leakage from blood vessel walls. It usually occurs first in the lower parts of the body; if the patient is standing, in the ankles and if the patient is lying down, in the back. A soft, usually painless swelling appears; the skin is tight and shiny. Firm pressure on the skin causes an indentation which remains when the pressure is removed. Oedema can occur for very many reasons. The most important are raised blood pressure in the veins, altered blood composition, and reduced lymph removal (lymphatic oedema). Pressure in the veins is raised by standing for a long period, varicose veins, thrombosis or heart failure. Oedema can also be the result of reduced blood protein, in kidney disorders such as the nephrotic syndrome, shortage of food protein (malnutrition) and serious liver disorders such as cirrhosis of the liver. Restricted removal of lymph can be caused by infestation with certain parasites, or by metastasis of cancer of the lymph nodes. Treatment of oedema is by treating the cause. For example, a patient with varicose veins should not remain standing for long. Protein shortage should be corrected by diet. Symptoms as well as cause should be treated. Bandaging the legs or wearing elastic stockings helps to force the fluid back into the vessels. Diuretics increase fluid excretion by the kidneys.