C42-15 A Rare Case of Daptomycin-Induced Hypersensitivity Pneumonia Presenting as Acute Hypoxic Respiratory Failure

Abstract Introduction Daptomycin is a lipopeptide antibiotic used to treat resistant gram-positive infections. Although generally well tolerated, it has been associated with rare but serious pulmonary toxicity, including eosinophilic and hypersensitivity pneumonitis. We present a case of acute hypoxic respiratory failure secondary to daptomycin-induced hypersensitivity pneumonia. Case Presentation A 58-year-old male with a history of type 2 diabetes mellitus, pulmonary embolism on long-term anticoagulation, prior tobacco use, presented with progressive shortness of breath over three days. He denied fever or sputum production. He had recently started on intravenous daptomycin and ertapenem for sacral osteomyelitis four days prior to symptom onset. On examination, he was tachypneic, using accessory muscles, and speaking in fragmented sentences with diffuse inspiratory crackles on auscultation. He required 3.5 liters per minute of supplemental oxygen via nasal cannula. Laboratory studies revealed leukocytosis (white blood cell count 18,900) and peripheral eosinophilia of three percent. B-type natriuretic peptide level was 32 picograms per milliliter and negative troponin. BioFire respiratory polymerase chain reaction and sputum cultures were negative. C-reactive protein was 22.1 milligrams per deciliter, erythrocyte sedimentation rate was 73 millimeters per hour, and procalcitonin was 0.43 nanograms per milliliter. Urine eosinophils were absent. Computed tomography (CT) of the chest with intravenous contrast demonstrated bilateral mild-to-moderate ground-glass opacities without consolidation or effusion. In the absence of infectious findings and given the temporal association with daptomycin initiation four days prior to symptom onset, a diagnosis of daptomycin-induced hypersensitivity pneumonia was made. Daptomycin was discontinued. The patient was treated with intravenous methylprednisolone 40 milligrams every eight hours for 24 hours resulting in marked improvement in symptoms and complete resolution of peripheral eosinophilia. He was transitioned to 40 mg of oral prednisone daily and was weaned off all supplemental oxygen by day four of admission and discharged on a prednisone taper with complete resolution of symptoms. Figure 1: CT chest demonstrating bilateral ground-glass opacities. Discussion Daptomycin-induced hypersensitivity pneumonia is an uncommon yet reversible cause of respiratory failure. The mechanism likely involves an immune-mediated alveolar inflammatory response with eosinophilic infiltration. Diagnosis is supported by temporal drug exposure, compatible imaging, and peripheral eosinophilia. Early drug withdrawal and corticosteroid therapy can result in rapid recovery. Conclusion Clinicians should maintain a high index of suspicion for daptomycin-induced hypersensitivity pneumonia in patients with hypoxemia following daptomycin exposure. Prompt recognition, cessation of the offending agent, and corticosteroid initiation can lead to complete clinical and hematologic resolution. This abstract is funded by: None