INTERSTITIAL LUNG DISEASE AS THE ONLY MANIFESTATION OF RHEUMATOID ARTHRITIS: CAN LUNGS BE THE SITE OF ORIGIN FOR RHEUMATOID ARTHRITIS-RELATED INFLAMMATION?

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TOPIC: Pulmonary Manifestations of Systemic Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Rheumatoid Arthritis (RA) is a systemic inflammatory disease primarily involving joints. Extra-articular manifestations of RA without joint disease are extremely rare. Lung disease represents a second common cause of death in RA after cardiovascular events (1). RA related lung disease includes interstitial lung disease (ILD), bronchiectasis and pleural disease. We report a patient with severe progressive RA related ILD, usual interstitial pneumonia (UIP) phenotype without joint involvement and poor outcome. CASE PRESENTATION: A 67-year-old female with one-year history of seropositive rheumatoid arthritis without joint involvement, on methotrexate presented with worsening shortness of breath. The exertional dyspnea started two years ago, and a screening low dose CT chest showed mild fibrotic changes at lung bases prior to methotrexate initiation. This time HRCT revealed progressive interstitial lung disease-usual interstitial pneumonia pattern, bilateral honeycombing of the lung bases and traction bronchiectasis. Pulmonary function test revealed restrictive ventilatory and severe gas transfer defect. Rheumatoid factor (RF) and Cyclic Citrullinated Peptide antibody (IgG) were 99.6 and above 250 respectively. ANA titer was low at 1:40, speckled pattern with normal ANCA. Methotrexate was discontinued and prednisone was started. She was discharged home on oxygen therapy but continued to decompensate with progressive hypoxemic respiratory failure eventually requiring high flow nasal canula. Repeat HRCT showed new ground glass opacities on left along with baseline interstitial changes. Flexible bronchoscopy with bronchoalveolar lavage showed no evidence of infection or malignancy. Patient was started on pulse dose steroids for possible ILD flare. However, her oxygen requirement and symptoms continued to worsen, and she was started on Mycophenolate Mofetil. With no improvement patient eventually opted for home hospice. DISCUSSION: Risk factors associated with RA-related ILD include older age, male sex, smoking and seropositivity for RF or anti-CCP antibodies. In addition, women with seropositive RA have increased risk of lung involvement than women without RA (2). Our patient presented with rapidly progressive ILD-UIP type without any joint disease and poor outcome. Methotrexate was less likely a culprit given the interstitial fibrotic changes present before drug initiation and rapid progression of ILD despite drug cessation. In our case lungs seem to be the primary site of RA related inflammation in setting of smoking causing citrullination of proteins and autoimmune responses (2). CONCLUSIONS: Although data on identification, management staging or monitoring of RA-related ILD without joint disease is lacking, clinicians should remain vigilant of this complication. RA-related UIP is more frequent with progressive disease and poor outcome and warrants early recognition and treatment (3). REFERENCE #1: G. Cafaro, A. Alunno, V. Valentini, M.C. Leone, E. Marcucci, E. Bartoloni, R. Gerli. The onset of rheumatoid arthritis: the joints or the lung? Reumatismo, 2016; 68 (4): 167-175 REFERENCE #2: Paolo Spagnolo, Joyce S. Lee, Nicola Sverzellati, Giulio Rossi, Vincent Cottin. The lung in Rheumatoid Arthritis. Focus on Interstitial Lung Disease. ARTHRITIS & RHEUMATOLOGY Vol. 70, No. 10, October 2018, pp 1544-1554 DOI 10.1002/art.40574 American College of Rheumatology REFERENCE #3: Hyun-Kyung Lee, MD; Dong Soon Kim, MD; Bin Yoo, MD; Joon Beom Seo, MD; Jae-Yoon Rho, MD; Thomas V. Colby, MD; Masanori Kitaichi, MD. Histopathologic Pattern and Clinical Features of Rheumatoid Arthritis-Associated Interstitial Lung Disease (CHEST 2005; 127:2019-2027) DISCLOSURES: No relevant relationships by Maria Azhar, source=Web Response No relevant relationships by Fatima Halilu, source=Web Response No relevant relationships by Qasim Muhammad, source=Web Response No relevant relationships by Matthew Woodford, source=Web Response