Edema primarily refers to swelling caused by fluid retention. This condition occurs when excess fluid accumulates in the body's tissues, leading to noticeable swelling in various parts of the body, such as the legs, ankles, and feet. The underlying causes of edema can include various medical conditions, such as heart failure, kidney disease, or liver issues, but the defining characteristic remains the accumulation of fluid. Understanding edema is essential for recognizing potential health issues and facilitating appropriate interventions or treatments.
The other options do not accurately describe edema. Tightening of muscles does not relate to fluid retention, while poor circulation might contribute to other health issues but is distinct from the specific condition of edema. Increased blood pressure may be associated with some causes of edema but does not define the condition itself.