(976) Perioperative Antibiotics: Is Drug-Induced Hypersensitivity Pneumonitis an Allergic Response?

Introduction: Drug-induced hypersensitivity pneumonitis (DIHP) is an immune-mediated interstitial disease that develops as a response to pharmacologic agents. This diagnosis of exclusion has late pulmonary findings and minimal externally visible signs. Case reports describe medications as a source of DIHP but mechanisms and risk factors for development remain unknown. Reported antibiotic allergies record visible changes or immediate anaphylaxis. We report a case of DIHP after Cefazolin, hypothesizing that repetitive use of antibiotics for perioperative surgical site infection (SSI) may contribute to long-term pulmonary sequelae in some patients.

Description: A 57-year old female with Hypertension, Coronary Artery Disease, Diabetes Mellitus and tobacco abuse was urgently transferred to the MICU for acute hypoxemic respiratory failure. She was readmitted for worsening shortness of breath within a one-month period and rapidly progressed to Vapotherm. Covid tests remained negative. At MICU transfer, nosebleeds attributed to oxygen therapy were noted and CT chest demonstrated new, characteristic mosaic attenuation of HP. Four months prior, a total hip arthroplasty was followed by prosthetic revision and subsequent treatment for MSSA bacteremia for septic arthritis. Six-weeks of IV cefazolin were prescribed with long-term antibiotics recommended. Systematic evaluation with autoimmune serologies, bronchoalveolar lavage and a VATS lung biopsy failed to confirm a diagnosis. Record review determined perioperative Cefazolin was administered for SSI prevention and played the most significant role in progressive worsening of lung function. She improved on steroids, PLEX, and antibiotic changes and was discharged on home oxygen with Pulmonology follow-up.

Discussion: Administration of antibiotics to prevent SSI when given in multiple, serial doses may potentiate immune-mediated responses. Rapidly progressive shortness of breath after multiple operations may be the only clue of DIHP. While case studies provide valuable insight into associations with medical conditions, more work is needed to delineate long-term impacts of antibiotic exposure that may result in DIHP.