What is edema?

• A. A disease
• B. An accumulation of protein in the tissues
• C. An accumulation of water in the tissues
• D. An accumulation of water and protein in the tissues

Answer: (C)

Edema is the accumulation of excess fluid in the tissues, especially in the interstitial spaces, which causes swelling. The defining idea is that the problem is a buildup of water in tissue spaces, not a primary accumulation of protein. This fluid buildup results from disruptions to normal fluid balance, such as increased capillary pressure, reduced plasma protein (oncotic) pressure, lymphatic drainage impairment, or increased capillary permeability. While protein can be present in the swollen area depending on the cause, the core feature of edema is the excess water in tissue spaces, making this option the most accurate description.