Edema is an abnormal swelling caused by the excessive pooling of fluids under the skin. There are several different kinds of edema based on the location of the excessive fluid retention, and the health risks associated with each type of edema also vary based on location. The two most commonly diagnosed forms are peripheral edema and pulmonary edema. Peripheral edema tends to form at the body's lowest point of gravity.For example, if a person is standing on their feet the problem may become noticeable at the ankles or on the tops of the feet. If a person is sitting down, the excess fluid will pool near the bottom of the spine or in the lower thigh. Pulmonary edema occurs in the lungs, and generally does not show any outward evidence of swelling. Again, the pooling of excess liquid is linked to gravity, so if a person lies down on their back the pulmonary fluid will spread along the backs of the lungs. If the person is sitting up, the fluid will collect in the bottom of the lungs. Mild edema symptoms can be managed by raising the swollen area above the level of the heart so that the fluid dissipates naturally. More severe edema can be treated with diuretics that reduce the amount of fluid the body produces.
