What is a common symptom of pleural effusion when lying down?

Cough is a common symptom associated with pleural effusion, particularly noticeable when a person is lying down. When fluid accumulates in the pleural space, it can exert pressure on the lungs and other structures within the thoracic cavity. This pressure might worsen when lying flat, which can trigger a reflexive cough as the body attempts to expel fluid or clear mucus build-up resulting from the limited lung expansion.

As fluid in the pleural space increases, it can also lead to difficulty breathing or discomfort in certain positions, prompting a cough. The act of coughing helps to open the airways and can temporarily alleviate some symptoms by mobilizing secretions. In contrast, dizziness, chest tightness, and loss of appetite are less directly tied to the positional effects of pleural effusion and do not commonly exhibit the same degree of association with changes in posture.