What condition is characterized by an increased accumulation of fluid in the lungs?

Pulmonary edema is characterized by the accumulation of excess fluid in the lungs, which can be visualized on imaging studies such as chest X-rays. This condition often results from various underlying issues, including heart failure, where the heart is unable to pump blood effectively, causing fluid to back up into the lungs. The increased fluid in the alveoli and interstitial spaces leads to impaired gas exchange, causing symptoms like shortness of breath, coughing, and difficulty breathing.

In contrast, pneumonia is an infection that inflames the air sacs in one or both lungs and may fill them with fluid, but is primarily infectious in nature rather than being a condition of fluid imbalance. Atelectasis refers to the collapse of part or all of a lung, preventing adequate air from filling that area but is not specifically characterized by fluid accumulation. Emphysema, part of chronic obstructive pulmonary disease (COPD), involves the destruction of alveolar walls and is primarily related to airflow obstruction rather than fluid accumulation. Hence, pulmonary edema is specifically noted for fluid buildup, distinguishing it from these other conditions.