A 70-year-old male with a history of rheumatoid arthritis presents with a persistent cough and fatigue. On physical examination, he has bilateral crackles in the lower lung fields. What could be the cause, and what are the next steps?
This patient's symptoms and findings could be suggestive of interstitial lung disease (ILD), a common extra-articular manifestation of rheumatoid arthritis. Other potential causes include infection, heart failure, or drug-induced pneumonitis. High-resolution computed tomography (HRCT) of the chest and pulmonary function tests would be the next appropriate steps to evaluate for ILD. If these tests confirm ILD, management often involves corticosteroids and potentially other immunosuppressive agents.