A previously healthy 3-year-old female child vaccinated with PCV-13 vaccine presented with a 10-day history of cough and a 5-day history of fever and dyspnea. Chest radiograph and ultrasound showed extensive right lung pneumonia, with a 2 cm pleural effusion and blood analysis revealed elevation of inflammatory markers. She was started on intravenous ampicillin and clindamycin and thoracentesis fluid was suggestive of empyema, with subsequent identification of Streptococcus pneumoniae serotype 3. Antibiotic therapy was changed to penicillin. Per protocol, she received six doses of intrapleural urokinase and the chest tube was removed on day 7, after 48H of no drainage.
Since admission, the patient continued to experience intermittent fever. Chest radiography on day six (Figure 1) and thoracic computed tomography (CT) scan on day eight (Figure 2) are shown below.
Figure 1. Chest radiograph showing a large round hypotransparency occupying almost the entire right hemithorax, and a hypotransparency in the lower third of the right pulmonary field, associated with blunting of the ipsilateral costophrenic angle.
Figure 2. Chest CT scan showing a gas containing fluid collection (9x8x6 cm) of the right hemithorax.
What is the most likely diagnosis?