noun, plural: oedemas or oedemata
Pathological oedema is the accumulation of abnormally large amounts of fluid in the intercellular tissue spaces. It may be due to a disease or venous (or lymphatic) obstruction. It may be demonstrated clinically as a swelling in the body caused by the fluid accumulating in the subcutaneous tissues. It may also be seen in one or more bodily cavities. Oedema may be designated according to the site affected. For instance, ascites pertain to the accumulation of serous fluid in the peritoneal cavities. Hydrothorax is oedema in the pleural cavity whereas hydropericardium is oedema in the pericardial sac. Anasarca pertains to the generalized oedema within the subcutaneous tissue.
In humans, pitting (i.e. the applying of pressure to a small area of the skin) is used to determine the presence of cutaneous or peripheral oedema. Oedema is established when an indentation on the skin persists after the pitting. Purtschers disease, Chandler syndrome, Rainbow symptom, Terrys syndrome, eczema, Romanas sign, Haradas syndrome, Extravascular lung water, suffocating gas, Arthus phenomenon, and Miltons disease are just a few of the many diseases that manifest oedema as a symptom.
Oedema also occur in plants, such as in cacti, fuchsias, and succulents. In botany, therefore, it pertains to the excessive accumulation of water in plant tissues resulting in swelling.