A 36-year-old woman with a history of Graves disease complains of lethargy, weight loss, and feeling faint often. Her Graves disease was treated successfully with total thyroidectomy secondary to...

A 36-year-old woman with a history of Graves disease complains of lethargy, weight loss, and feeling faint often. Her Graves disease was treated successfully with total thyroidectomy secondary to inadequate response to antithyroid medications and radioactive iodine. Physical exam reveals multiple patches of skin depigmentation and orthostatic hypotension. The physician suspects adrenal insufficiency and confirms her diagnosis with a morning cortisol level and plasma ACTH. What is the most likely cause of her adrenal insufficiency?

A. Autoimmune adrenalitis

B. Long-term exogenous levothyroxine therapy

C. Undiagnosed coagulation disorder

D. Long-term exogenous glucocorticoid therapy

E. TB reactivation