<prompt> A 27-year-old man with history of alcoholism and repeated bouts of aspiration pneumonia comes to the emergency room with a high fever and pleuritic chest pain. Physical examination reveals dullness on percussion and absence of breath sounds in the right lower lung field. A chest X-ray demonstrates pleural fluid on the right side. Thoracentesis returns a thick, foul-smelling fluid. Which of the following is the most likely diagnosis?ChylothoraxEmpyemaHemothoraxPneumothorax  <response>: Pleuritis inflammation of the pleura may result from the extension of any pulmonary infection to the visceral pleura. Pyothorax refers to a turbid effusion containing many neutrophils. Empyema is a variant of pyothorax in which thick pus accumulates within the pleural cavity, often with loculation and fibrosis. Hydrothorax refers to transudation of edema fluid into the pleural cavity. 