A Case of Fulminant Type 1 Diabetes Mellitus, Secondary Adrenal Insufficiency, and Hypothyroidism after Pembrolizumab Administration

Abstract

After starting the immune checkpoint inhibitor pembrolizumab in October X-1 for postoperative recurrence of transverse colon cancer, a 77-year-old man with no history of diabetes mellitus visited our hospital in January X with complaints of general fatigue, decreased appetite, thirst, and heavy drinking. He was urgently admitted to the hospital with diabetic ketosis: random blood glucose 341 mg/dL, HbA1c 7.6 %, urinary ketone (2 +), and pH 7.341. His fasting serum C-peptide level was 0.22 ng/mL, and his anti-GAD antibody was negative, so a diagnosis of fulminant type 1 diabetes mellitus was made. The patient was also found to have low cortisol levels with normal ACTH levels and was diagnosed with secondary hypoadrenocorticism after load tests. In addition, he had FT40.16 ng/dL, TSH 111.67 μ IU/mL, and hypothyroidism. Intensive insulin therapy, hydro-cortisone, and levothyroxine were administered sequentially. This is an extremely rare case in which pembrolizumab caused three endocrine disorders almost simultaneously. We consider this case to be informative regarding the management of endocrinologic immune-related adverse events, and we herein described the findings of this case with a review of the literature.