Abstract Introduction Daptomycin is a lipopeptide antibiotic commonly used to treat infections caused by Gram-positive bacteria resistant to other antibiotics, including prosthetic joint infections. Pulmonary toxicity is a rare but recognized complication, most often manifesting as eosinophilic pneumonia. However, daptomycin-induced lung injury can also occur without eosinophilia, which may complicate diagnosis. We present a case of daptomycin-induced lung injury presenting with hypoxemic respiratory failure and radiographic infiltrates, but without peripheral or bronchoalveolar lavage (BAL) eosinophilia. Case Description A 64-year-old male with hypertension, obesity, polymyalgia rheumatica, and multiple prior left knee surgeries was treated for prosthetic joint infection with intravenous daptomycin and rifampin, intended for a 42-day course. Three weeks into therapy, he developed fever, cough, dyspnea, and hypoxemia requiring hospitalization. Chest CT revealed bilateral upper-lobe predominant ground-glass and reticular opacities. Empiric antibiotics (cefepime and vancomycin) were initiated, and daptomycin was discontinued due to suspected drug-induced lung injury. Bronchoscopy showed thick secretions; cultures were negative, and BAL analysis demonstrated monocyte predominance without eosinophils. The patient was discharged on home oxygen and a tapering course of prednisone (starting at 50 mg, tapered to 5 mg). At two-month outpatient follow-up, he reported gradual improvement in dyspnea and dry cough, with near-complete radiologic resolution of infiltrates. His staphylococcal prosthetic joint infection was managed with intravenous vancomycin, which was subsequently discontinued. Discussion This case underscores that daptomycin-induced lung injury can occur in the absence of eosinophilia. While eosinophilic pneumonia is the most commonly recognized pulmonary toxicity associated with daptomycin, there is increasing evidence that lung injury may present without peripheral or BAL eosinophilia. Diagnosis in this patient was based on the temporal association with daptomycin exposure, characteristic radiographic findings, exclusion of infectious etiologies, and clinical improvement following drug discontinuation and corticosteroid therapy. The monocyte-predominant BAL pattern in this case suggests that daptomycin-induced lung injury may involve other immune pathways or direct cytotoxic effects, rather than eosinophilic infiltration alone. This case adds to the growing body of literature indicating that the absence of eosinophilia does not exclude the diagnosis of daptomycin-induced lung injury. Conclusion Daptomycin-induced lung injury should be considered in patients presenting with new pulmonary infiltrates and hypoxemic respiratory failure during therapy, even when eosinophilia is absent. Diagnosis relies on clinical suspicion, temporal relationship to daptomycin exposure, and exclusion of other causes. Prompt discontinuation of daptomycin and initiation of corticosteroid therapy are essential for recovery. This abstract is funded by: None
Naveed et al. (Fri,) studied this question.