In cases of pleural effusion, what type of breath sounds are typically heard?

In the case of pleural effusion, the accumulation of fluid in the pleural space affects lung expansion and reduces airflow to the areas of the lung adjacent to the effusion. Consequently, during auscultation, decreased or absent breath sounds are typically heard over the site of the effusion. This happens because the presence of fluid in the pleural cavity obstructs the transmission of sound generated by the airflow in the airways. As a result, the examiner may find that breath sounds are significantly diminished or completely absent in the affected area, indicating compromised lung function in that region.

The other options reflect different respiratory issues: wheezing is characteristic of narrowed air passages, often due to conditions such as asthma or bronchospasm; stridor indicates upper airway obstruction and is not associated with pleural effusion; and rhonchi are often heard with conditions like bronchitis or when there are secretions in larger airways, which also does not correlate with the sound alterations seen in pleural effusion. Thus, the identification of diminished or absent breath sounds is specifically indicative of the presence of fluid in the pleural space.