Spontaneous Polymicrobial Empyema in an Immunocompetent Patient: The Role of Imaging Accuracy.

Empyema, a bacterial infection in the pleural space, is a subtype of complicated parapneumonic effusion. It is best identified through clinical presentation, imaging (chest X-ray, ultrasound, and CT), and microbiological confirmation. We present the case of a 20-year-old female with a history of bronchiectasis who developed spontaneous polymicrobial empyema. Upon arrival, the patient had an oxygen saturation of 93% on room air but later developed tachypnea and tachycardia. Imaging revealed a trapped lung with associated empyema and gas bubbles rather than a true hydropneumothorax. Cultures tested positive for Streptococcus anginosus, Prevotella intermedia, and Parvimonas micra. The patient underwent pulmonary decortication surgery and therapeutic bronchoscopy, received a four-week course of IV piperacillin-tazobactam, and showed significant improvement upon follow-up. This case underscores the importance of accurate radiologic interpretation and early multidisciplinary intervention in high-risk patients. It highlights the diagnostic challenge of differentiating a trapped lung with empyema from hydropneumothorax, emphasizing the role of precise imaging analysis in clinical decision-making.