C42-07 Is Bronchoalveolar Lavage Necessary for the Diagnosis of Daptomycin Induced Lung Injury?

Abstract Introduction Daptomycin is a cyclic lipopeptide antibiotic increasingly used against resistant Gram-positive organisms, including methicillin-resistant Staphylococcus aureus (MRSA). Although generally well tolerated, rare adverse events such as acute eosinophilic pneumonia and pulmonary toxicity have been reported. Typical features include dyspnea, cough, and rapid escalation of oxygen requirements, often within the first week of therapy. Bronchoalveolar lavage (BAL) may reveal alveolar eosinophilia, but diagnosis is frequently clinical, especially when invasive procedures carry high risk. Case Presentation An 89-year-old male with coronary artery disease, hypertension, and peripheral vascular disease presented with altered mental status, left-sided weakness, and facial droop. Stroke evaluation was negative. Admission blood cultures grew MRSA, and vancomycin was initiated. Due to persistent bacteremia, therapy was switched to daptomycin, followed by ceftaroline for synergy, resulting in culture clearance within 48 hours. Transesophageal echocardiography revealed a mobile aortic valve vegetation, confirming infective endocarditis. Approximately one week after starting daptomycin, he developed progressive dyspnea with escalating oxygen needs, requiring high-flow nasal cannula at 14 L/min. Imaging showed new bilateral infiltrates and pleural effusions. He remained afebrile with stable leukocyte count, negative procalcitonin, and no evidence of fluid overload or pulmonary embolism. Chest CT revealed bilateral ground-glass opacities with small effusions. Given the temporal association and lack of alternative explanations, daptomycin-induced lung injury was suspected. Daptomycin was discontinued, and high-dose intravenous corticosteroids were started, followed by a tapering oral regimen. BAL was not pursued due to clinical instability. Over four weeks, the patient improved, with oxygen requirements decreasing to 6 L/min and imaging demonstrating resolution of infiltrates. Discussion Daptomycin pulmonary toxicity is rare but clinically significant, often mimicking infection or cardiogenic pulmonary edema. Presentation typically includes acute respiratory failure and bilateral infiltrates, with eosinophilia occasionally seen in peripheral blood or BAL. In many frail or unstable patients, diagnosis relies on clinical suspicion and the temporal relationship to therapy initiation. In this case, the patient’s hypoxic deterioration shortly after daptomycin initiation, absence of other etiologies, and subsequent improvement following drug withdrawal and corticosteroid therapy strongly supported the diagnosis. While evidence for steroids is limited to case reports, their use may accelerate recovery. Conclusion Daptomycin-induced lung injury should be considered in patients with new respiratory symptoms and infiltrates within 7-14 days of therapy. Early discontinuation of the agent is essential, and treatment should not be delayed by awaiting BAL results. Corticosteroids may be beneficial in facilitating recovery. This abstract is funded by: None