Annette Eom, Mutsumi Kioka
A 25-year-old man developed acute hypoxaemic respiratory failure after 21 days of tigecycline therapy for osteomyelitis caused by multidrug-resistant organisms. Chest computed tomography demonstrated bilateral consolidations, ground-glass opacities, interlobular septal thickening, small bilateral pleural effusions and mediastinal lymphadenopathy. Bronchoalveolar lavage (BAL) revealed marked eosinophilia (99%-100%) despite minimal peripheral eosinophilia. Alternative causes, including infectious, parasitic, autoimmune and other potential aetiologies, were carefully evaluated. Based on the temporal relationship with tigecycline exposure, marked BAL eosinophilia, exclusion of alternative causes and the overall clinical presentation, probable tigecycline-induced acute eosinophilic pneumonia (AEP) was diagnosed. Tigecycline was discontinued, cefiderocol was initiated for concomitant multidrug-resistant Acinetobacter baumannii, and systemic corticosteroid therapy was administered, followed by progressive clinical and radiographic improvement. Although the clinical response followed multiple simultaneous interventions and therefore does not establish causality, the overall findings support tigecycline as the probable causative agent. To our knowledge, this is the first reported case of probable tigecycline-associated AEP. This case highlights the importance of considering AEP in patients who develop unexplained respiratory deterioration during tigecycline therapy and underscores the diagnostic value of BAL, particularly in the absence of marked peripheral eosinophilia.