Occult pneumococcal bacteremia and empyema without preceding pulmonary parenchymal involvement.

We have presented a case of pneumococcal empyema without evidence of pulmonary parenchymal infection. We postulate that the pleural space was hematogenously seeded from an unexplained pneumococcemia. This manifestation of pneumococcal infection is unusual, particularly since the patient was receiving adequate antibiotic therapy before the radiologic or clinical appearance of the empyema. This emphasizes the need for diagnostic thoracentesis when the clinical situation changes, even after appropriate antimicrobial therapy is begun.