The significance of parapneumonic pleural effusions developing during antibiotic treatment for pneumonia.

BACKGROUND: There are little data regarding the outcomes of parapneumonic pleural effusions that first appear during antibiotic treatment of the underlying pneumonia. OBJECTIVES: To assess the outcome of patients who develop a parapneumonic effusion while on antibiotic therapy. METHODS: Patients admitted to the John Dempsey Hospital with a discharge diagnosis of pneumonia were identified retrospectively. Patients with minimal or no effusion on admission chest radiograph who subsequently developed a parapneumonic effusion during their hospital stay were included. The characteristics of the effusions and the patient outcomes were studied. RESULTS: Twenty-eight (3%) of 1,028 patients developed a parapneumonic effusion while in the hospital. Seventy-one percent of the parapneumonic effusions were small (occupying less than one-third of the hemithorax) and 29% were moderate (occupying between one-third and two-thirds of the hemithorax). No patients required tube thoracostomy or other drainage procedure. CONCLUSION: Patients with pneumonia who develop a parapneumonic effusion while receiving antibiotic therapy are unlikely to develop empyema or a complicated effusion requiring drainage.