Case Presentation: A 31-year-old woman with anxiety presented with progressively worsening shortness of breath and dry cough for one month. She had no joint complaints, rash, weakness, neuropathic symptoms, or history of thrombosis in the past. Upon presentation, she was found to be afebrile, hypertensive to 140/90 mm Hg, not tachycardic, tachypneic to 22, and hypoxic to 90% on room air, saturating 98% on 2L nasal cannula. Exam was notable for clear lungs and no signs of synovitis or limitation of range of motion in any joint. Labs were significant for transaminitis with AST 72 and ALT 69, along with high anion gap metabolic acidosis with bicarbonate of 18 and anion gap 17. EKG showed sinus rhythm. CTA was negative for pulmonary embolism but showed evidence of pulmonary fibrosis, hilar and mediastinal lymphadenopathy, and a small pericardial effusion. Given the imaging findings, differential diagnosis included idiopathic pulmonary fibrosis, post-COVID inflammatory syndrome, sarcoidosis, infection, secondary to environmental exposures, and other autoimmune etiology. Rheumatologic workup was initiated, and she was found to have an elevated RF 212, anti-CCP 140, and anti-SSA antibody >8. She was thought to have RA-associated interstitial lung disease. She was also found to have severe pulmonary hypertension and a severely enlarged right atrium on transthoracic echo. She was started on steroid therapy, apixaban, sildenafil, and furosemide, and discharged with home oxygen with plans for follow up with rheumatology and pulmonology.
Discussion: Rheumatoid arthritis is a systemic inflammatory disorder that affects approximately 1% of the population, and most commonly affects the joints. It also has extra-articular manifestations including subcutaneous nodule formation, vasculitis, inflammatory eye disease, and lung disease. Respiratory symptoms may even precede joint symptoms in 10-20% of cases. Occasionally they can be masked due to poor functional status from joint disease. Interstitial lung disease is the primary pulmonary manifestation of RA. In this case, our patient presented with respiratory symptoms and was found to have interstitial lung disease on imaging. Workup to further assess this etiology was consistent with RA-associated lung disease, despite her lack of joint involvement.
Conclusions: Hospitalists should be aware that rheumatoid arthritis can present with only lung involvement initially, and that making the specific ILD diagnosis will guide treatment.