Which of the following is a potential symptom of pleural effusion?

Shortness of breath is a potential symptom of pleural effusion because the accumulation of fluid in the pleural space can restrict lung expansion, leading to decreased lung capacity and impairing normal breathing. When there is excess fluid, it can push against the lungs, making it difficult for them to expand fully during inhalation. This results in the sensation of dyspnea, or shortness of breath, particularly during physical exertion or even at rest, depending on the severity of the effusion.

While other symptoms like fever, nausea, and coughing up blood can be associated with different respiratory or systemic conditions, they are not direct symptoms related to pleural effusion itself. Fever might indicate an infectious process, nausea may stem from various other issues, and coughing up blood typically points towards specific pathologies like pulmonary embolism or certain lung cancers, rather than being a characteristic symptom of pleural effusion. Therefore, shortness of breath stands out as the most relevant symptom for this condition.