What is pulmonary edema characterized by?

Pulmonary edema is primarily characterized by fluid accumulation in the lungs, specifically within the alveoli, which are the tiny air sacs where gas exchange occurs. This condition can arise from various causes, such as heart failure, where the heart is unable to pump blood effectively, leading to increased pressure in the blood vessels of the lungs. As a result, fluid seeps into the alveoli, impairing gas exchange and causing symptoms like shortness of breath, difficulty breathing, and sometimes a feeling of suffocation.

While other options mention symptoms or conditions related to respiratory issues, they do not accurately define pulmonary edema. For instance, a cough that produces mucus indicates conditions like bronchitis or infections, constriction of the airways typically relates to asthma or COPD, and inflammation of the lungs might refer to pneumonia or other inflammatory processes. However, the defining feature of pulmonary edema remains the abnormal accumulation of fluid, which significantly affects both respiratory function and overall oxygenation.