ABSTRACT Objective: We report a patient with type 2 amiodarone-induced thyrotoxicosis (AIT) treated with high-dose glucocorticoids who subsequently had Pneumocystis jirovecii pneumonia (PJP). Methods: Current guidelines recommend high doses of glucocorticoids for restoring euthyroidism in patients with type 2 AIT. In this case study, we discuss a potential life-threatening pitfall of high-dose glucocorticoid use in these patients. Results: A 63-year-old man with a history of paroxysmal atrial fibrillation previously treated with oral amiodarone was seen for weight loss, tremors, and fatigue. He was biochemically hyperthyroid (suppressed thyroid-stimulating hormone, elevated free thyroxine and free triiodothyronine). Oral dexamethasone was started for type 2 AIT, with dramatic improvement over 2 months. He later developed progressive shortness of breath and hypoxic respiratory failure requiring mechanical ventilation. Infectious workup revealed PJP. Despite aggressive treatment measures, he suffered numero...