Pulmonary Actinomycosis Causing an Unusual Presentation in a Patient with COPD: A Case Report.

We present the case of a 63-year-old male patient with a history of chronic obstructive pulmonary disease (COPD), heavy smoking, and poor dental hygiene, who presented with progressive dyspnea, fever, and a productive cough. The patient was initially evaluated for pneumonia, but a chest radiograph revealed a right-sided pleural effusion. Further analysis of the pleural fluid showed an exudative effusion. Histopathological examination of a pleural biopsy sample identified gram-positive branching filamentous rods with yellow sulfur granules, consistent with a diagnosis of pulmonary actinomycosis. The patient was initially treated with intravenous amoxicillin/sulbactam, later switched to oral amoxicillin. This case highlights a rare clinical presentation of pleural effusion in a patient with pulmonary actinomycosis.