Abstract Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a serious extra-articular manifestation of RA, with clinically significant disease affecting up to 10% of patients with RA. RA-ILD without synovitis or other signs of active RA often presents a diagnostic challenge. Case Report A 71-year-old male with a past medical history of squamous cell lung carcinoma and treatment course including irinotecan, atrial fibrillation, and recent pulmonary embolism 3 months prior to presentation was admitted to the hospital for 3 days of worsening fever despite oral antibiotics, acute hypoxemic respiratory failure, and new multifocal opacities on CT chest. At the time of hospitalization, he had no diagnosis of rheumatoid arthritis, but he had been seen in outpatient rheumatology clinic 2 months prior for migratory arthralgias and high titer positive RF and CCP. ILD was also not formally diagnosed prior to this hospitalization. There was no active synovitis on exam in rheumatology clinic or on presentation to the hospital. During the initial phase of the hospitalization, he had fevers and worsening oxygen requirements from 2-3 liters up to 15 liters. Rheumatology, infectious disease, and pulmonology were consulted. CT chest showed diffuse consolidative changes with unknown chronicity with regards to treatment with irinotecan and lurbinectedin therapy (Figure). Complete infectious workup, including induced sputum for pneumocystis pneumonia, was negative. Treatment with broad spectrum intravenous antibiotics resulted in no clinical improvement. The differential diagnosis for his respiratory failure included pulmonary irinotecan toxicity and RA-ILD. Empiric prednisone 1 mg / kg orally resulted in gradual resolution of his oxygen requirement over one week. His case was discussed at multidisciplinary ILD clinical conference and a diagnosis of RA-ILD was made based on his imaging findings, known seropositivity for RF and CCP, failure to improve with antibiotics, and response to steroids despite having no other evidence of active rheumatoid arthritis. He was discharged without supplemental oxygen on hospital day 12 with pulmonary follow up for consideration of additional RA and ILD specific therapeutics, though a clinical trial for his lung cancer to date has precluded his treatment start. Novelty/Importance RA-ILD can have severe and acute presentations and should be considered even in the absence of known RA diagnosis or other manifestations of active RA. While this patient did not have known rheumatologic disease, RA-ILD is a risk factor for development of lung cancer including SCLC, and it is possible that he had unrecognized RA-ILD prior to his SCLC diagnosis. This abstract is funded by: None
Sullivan et al. (Fri,) studied this question.