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

There are little data regarding the outcomes of parapneumonic pleural effusions that first appear during antibiotic treatment of the underlying pneumonia.

To assess the outcome of patients who develop a parapneumonic effusion while on antibiotic therapy.

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.

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.

Patients with pneumonia who develop a parapneumonic effusion while receiving antibiotic therapy are unlikely to develop empyema or a complicated effusion requiring drainage.