A 58-year-old woman with RA on methotrexate and adalimumab develops a new dry cough, dyspnoea, and bilateral ground-glass opacities on HRCT. BAL is negative for infection. The MOST likely diagnosis and the APPROPRIATE management change is:
- A Methotrexate pneumonitis; stop methotrexate, administer corticosteroids ✓
- B RA-ILD; add mycophenolate mofetil and continue adalimumab
- C TNF-inhibitor-induced ILD; switch to rituximab
- D Pneumocystis jirovecii pneumonia; add co-trimoxazole
Correct answer: A. Methotrexate pneumonitis; stop methotrexate, administer corticosteroids
Explanation
Methotrexate pneumonitis is a hypersensitivity reaction that can occur at any dose or duration, presenting with subacute dyspnoea, dry cough, fever, and bilateral ground-glass opacities with BAL showing lymphocytosis but no organisms. Management requires immediate cessation of methotrexate and corticosteroid therapy. It must be distinguished from RA-ILD (which can be exacerbated by methotrexate) and opportunistic infection. MTX pneumonitis is not dose-dependent and can recur on rechallenge; methotrexate should generally not be restarted.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.