Abstract Background Cytoplasmic ANCA (c-ANCA) vasculitis is an autoimmune small and medium-vessel vasculitis classically associated with PR3-ANCA. The primary syndrome is granulomatosis with polyangiitis (GPA), which causes necrotizing granulomatous inflammation most often in the respiratory tract and kidneys. Pathogenesis is due to loss of tolerance to PR3, leading to ANCA-mediated neutrophil activation and vessel injury. Diagnosis involves clinical assessment, ANCA serologies, and histopathology, as other autoimmune markers may not be abnormal at presentation of symptoms. Here we present the case of a 46-year-old woman with autoimmune conditions who developed ARDS secondary to undiagnosed GPA. Case Presentation A 46-year-old woman with rheumatoid arthritis (RA) on hydroxychloroquine and adalimumab presented for shortness of breath and one episode of self-resolved, non-massive hemoptysis. She quickly decompensated, requiring intubation for severe ARDS. Initial infectious and autoimmune (C3/C4) workups were unremarkable. Bronchoalveolar lavage (BAL) fluid was grossly bloody from the initial aliquot, making it difficult to determine whether the return became progressively bloodier. Cytologic examination revealed hemosiderin-laden macrophages, supporting a diagnosis of diffuse alveolar hemorrhage (DAH) as the cause of ARDS. The patient was treated per ARDS protocol with IV dexamethasone prior to extubation to HFNC. New results after extubation showed elevated C3/C4 and positive serologies for PR3-ANCA and c-ANCA, suggesting GPA as hematuria and renal injury were also present. Renal biopsy revealed focal necrotizing glomerulonephritis with 25% crescents, confirming pauci-immune glomerulonephritis. She was then treated with pulse dose prednisone and rituximab induction. The patient was then able to be weaned from supplemental O2 and returned to her baseline. She was discharged on a steroid taper with rheumatology follow up for further rituximab infusions. Discussion While respiratory involvement is common in patients with GPA, DAH is a severe manifestation which carries a high morbidity and mortality. Although progression to ARDS is rare, clinicians should remain vigilant for vasculitic and granulomatous causes of ARDS, especially in patients with known autoimmune conditions. Understanding the etiology of ARDS can ensure that appropriate treatment is initiated, as in this patient who correctly received pulse dose steroids for GPA. Conclusion ARDS has many etiologies and requires a detailed workup, as identification of the underlying cause affects management and patient outcomes. When DAH is identified as the cause of ARDS, GPA should remain on the differential, as appropriate steroid doing and prompt immunotherapy is required to treat the inciting factor and prevent relapse. This abstract is funded by: None
Essajee et al. (Fri,) studied this question.