What does edema refer to?

• A. Destruction of tissue
• B. Decreased blood flow
• C. Infection of tissue
• D. Swelling caused by fluid accumulation

Answer: (D)

Edema is swelling caused by fluid accumulation in tissue spaces. It happens when fluid leaks out of capillaries into the surrounding interstitial area or when drainage is impaired, leading to puffiness in areas like the legs or, in the lungs, pulmonary edema. This focuses on fluid buildup rather than cell death, reduced blood flow, or infection. Tissue destruction involves damaged or dead cells; decreased blood flow causes ischemia; infection brings pathogens and inflammatory signs—none of these definitions describe fluid-backed swelling the way edema does.