What defines pulmonary edema in medical terms?

Pulmonary edema is specifically characterized by the accumulation of fluid in the lungs, which leads to impaired gas exchange and can cause significant breathing difficulties. When fluid fills the air sacs (alveoli) in the lungs, it interferes with the normal oxygen transport into the bloodstream and carbon dioxide removal from the body, resulting in symptoms such as shortness of breath, a feeling of suffocation, and in severe cases, it can lead to respiratory failure.

This condition can arise from various causes, including heart problems, high blood pressure, and infections, and understanding its definition is crucial for proper diagnosis and treatment. The other options pertain to fluid accumulation in different areas of the body, which do not relate directly to the lungs or respiratory function, thereby distinguishing pulmonary edema specifically as a lung-related issue.