A simple pleural effusion or not?

A 60-year-old man presented with a 2-week history of progressive dyspnea and bilateral leg edema. He had undergone a prosthetic mitral valve replacement 9 years earlier. The patient was in respiratory distress (respiratory rate 32/min, oxygen saturation 86% on air, heart rate 124/min, blood pressure 109/56 mmHg). Examination revealed bilateral lung crackles and reduced air entry with dullness to percussion and elevated jugular venous pressure. The electrocardiogram showed sinus tachycardia. A chest X-ray (CXR) (Figure 1) and bedside lung ultrasonography were performed (Figure 2A). A diagnosis of a large pleural effusion was made and urgent thoracocentesis was considered in view of the patient’s respiratory distress. A repeat ultrasonographic scan with adjusted angulation to identify the most suitable entry point for the chest drain (Figure 2B) yielded new results that led to the cancellation of the thoracocentesis.