Identifying drug-induced lung injury in a patient with rheumatoid arthritis

THE CASE A 44-year-old man with severe rheumatoid arthritis (RA) and hepatitis C was admitted to the medical ICU with methicillin-sensitive Staphylococcus aureus septic arthritis of the right knee requiring surgical debridement. He had a history of methicillin-resistant S aureus skin infections and a remote history of polysubstance abuse, including injection drug use. Sepsis developed, and the patient had acute respiratory failure requiring mechanical ventilation. Ventilator-associated pneumonia ensued, and the patient was treated with intravenous cefepime and vancomycin. He also received nafcillin for septic arthritis and warfarin for deep venous thrombosis of the right lower extremity. A chest radiograph showed a resolving retrocardiac opacity with low lung volumes and small bilateral pleural effusions, but otherwise clear lung parenchyma. The patient's clinical recovery paralleled the radiographic improvement, and he was weaned from mechanical ventilation and transferred to the hospital ward. The patient's RA had been treated with adalimumab without known complications, but this therapy was discontinued for insurance-related reasons approximately 1 month before hospitalization. While hospitalized, he was treated with oral prednisone (20 mg daily) and sulfasalazine (1 g twice daily). He continued to receive vancomycin, cefepime, and nafcillin. His other medications included esomeprazole, tamsulosin, oral morphine, potassium chloride, and metoclopramide. Five days after the initiation of sulfasalazine therapy, he had a low-grade fever, subacute breathlessness, and mild hypoxemia without cough or hemoptysis. A chest radiograph taken 11 days after sulfasalazine treatment was started demonstrated bilateral infiltrates with right lung perihilar consolidation, early left mid-lung zone infiltrate, and bilateral perihilar interstitial prominence (Figure 1). Pulmonary consultation was requested.