2020 Volume 63 Issue 10 Pages 711-716
Our patient is a 77-year-old man with a history of type 2 diabetes and squamous cell carcinoma of the lung. Five months after initiating treatment with pembrolizumab, he was admitted to our hospital due to conscious disturbance. His HbA1c levels were maintained at 6.0 % to 6.5 % while taking an oral antidiabetic drug. Five days before admission, his blood glucose levels were 249 mg/dL with ketonuria at a regular outpatient visit. He developed malaise three days later. On the day of admission, he visited our emergency room due to impaired consciousness and was diagnosed with diabetic ketoacidosis due to fulminant type 1 diabetes. We administered large amounts of fluid and continuous insulin infusion. However, he succumbed 17 h after the admission. A histopathological analysis revealed pathological changes characteristic of fulminant type 1 diabetes, such as decreased pancreatic β and α cells and CD3-positive T cell infiltration. Additionally, we noted a decreased expression of programmed cell death ligand 1 in the pancreatic islets. When immune checkpoint inhibitors are administered to diabetic patients, it is crucial to notify professional healthcare providers and patients of the risk of immune-related type 1 diabetes development.
