A Rare Case of a Splenic Abscess as the Origin of Illness in Exudative Pleural Effusion.

Background: Pleural effusion, the presence of fluid within the pleural space, is a common condition secondary to a wide range of pathological causes. Splenic abscess, which is rare, has previously been described as a cause of exudative pleural effusion. Splenic abscess is thought to be associated with bacteremia, iatrogenic inoculation, or hematogenous spread from another bacterial focus. However, there are no documented cases of pleural effusion with the spleen as the source of infection. Case Presentation: An 80-year-old male presented with shortness of breath, weight loss, and fever. Imaging revealed a left pleural effusion and a splenic mass. Following several unsuccessful attempts to drain the effusion, attention shifted to the splenic mass, which proved to be a bacterial abscess. After targeted antibiotic treatment for the splenic abscess and surgical decortication for pleural adhesions, the patient showed significant improvement and was discharged. Conclusions: This clinical scenario underscores the importance of identifying and addressing the source of pleural effusion, including consideration of splenic abscess as the primary process. By process of exclusion, we determined that the spleen was the origin of the disease, challenging the conventional perception of the spleen as exclusively a secondary locus of infection, without direct iatrogenic inoculation or bacteremia. The patient's presentation, hospital course, and response to treatment should encourage clinicians to consider a wider range of differential diagnoses for the primary pathologies underlying pleural effusions, facilitating earlier identification and intervention.