Combined immune checkpoint inhibitor–induced type 1 diabetes: a rare but serious endocrinopathy

Cancer immunotherapies have a class of medications called checkpoint inhibitors that can induce endocrinopathies including hypothyroidism, hypophysitis, and adrenalitis. This case illustrates a 72-year-old woman with recently diagnosed non-small cell lung cancer (NSCLC) who developed immune-mediated hypothyroidism and subsequent type 1 diabetes mellitus (T1DM) presenting as diabetic ketoacidosis (DKA) after 3 months of combination immunotherapy with nivolumab and ipilimumab. After her hospitalization, she was discharged on insulin. Our clinical case not only provides more literature on the risks involved with immunotherapy but also shows a rare outcome with checkpoint inhibitor-induced T1DM.