causes and concerns for fluid retention
Edema definition and facts. Edema is a swelling, usually of the legs, feet, and/or hands due to the accumulation of excessive fluid in the tissues. The edema that occurs in diseases of the heart, liver, and kidneys is mainly caused by salt retention, which holds the excess fluid in the body.
(At other times, edema is caused by heart, kidney or liver disease that causes water to accumulate in the lungs, abdomen and elsewhere.) Fluid usually pools in the feet, ankles and legs, but it can also be more generalized throughout the body. Swelling can either disappear overnight or persist.