NBME Form 26 Practice Test

In the context of pleural effusion, a physical examination would demonstrate a decrease in fremitus. Fremitus refers to the vibration felt on the chest wall when a person speaks and is transmitted through lung tissue. Normally, when a patient speaks, these vibrations are felt more prominently over areas where lung tissue is normal and closely adheres to the chest wall.

In the case of a pleural effusion, fluid accumulates in the pleural space, which acts as a barrier between the lung and the chest wall. This fluid interferes with the transmission of sound vibrations. As a result, when the patient speaks, the vibrations are dampened or reduced in areas where the effusion is present. Consequently, there would be diminished or absent fremitus over the site of the effusion during the physical examination.

Understanding the pathophysiological impact of the fluid accumulation in the pleural space helps clarify why decreased fremitus is specific to pleural effusion and not seen in conditions such as pneumonia, where consolidation usually increases fremitus due to lung tissue density changes, or in pneumothorax, where the lung is collapsed but does not involve fluid buildup.