Olanzapine-induced peripheral eosinophilia and eosinophilic pleural effusion: A case report

RATIONALE: Eosinophilic pleural effusion (EPE) is an eosinophil count ≥10% in pleural effusion, which is a rare condition in drug therapy. PATIENT CONCERNS: We describe the case of a 70-year-old Alzheimer patient who was taking olanzapine for 2 months for the treatment of depression, and developed peripheral eosinophilia and bilateral EPE. DIAGNOSES: Olanzapine-induced peripheral eosinophilia and eosinophilic pleural effusion was diagnosed. INTERVENTIONS: Olanzapine was discontinued, and repeated drainage of fluid from the pleural cavity was performed. OUTCOMES: All symptoms—as well as the EPE—were resolved 6 months later. LESSONS: This case is a reminder that olanzapine may be a potential agent for EPE, and that this should be considered in clinical practice.