Abstract
INTRODUCTION: Autoimmune pancreatitis (AIP) is characterized by the involvement of autoimmune mechanisms and is classified as type 1, together with infiltration of IgG4-positive cells, and type 2 with poor serological abnormal findings. In clinical practice, AIP is often treated with steroid therapy. PATIENT CONCERNS: An 81-year-old Japanese woman had thirst and appetite loss in the previous 5 days; thus, she visited a local doctor. The patient had no abdominal or back pain. She had no history of diabetes mellitus, but at that time blood glucose level and HbA1c were as high as 633 mg/dL and 9.7%, respectively, and she was referred to our institution. DIAGNOSIS: Based on various clinical findings in this patient, we diagnosed her with hyperglycemic and hyperosmolar syndrome and depletion of insulin secretory capacity induced by type 2 AIP. INTERVENTIONS AND OUTCOMES: The patient completely recovered without steroid therapy and was withdrawn from insulin therapy. CONCLUSIONS: We should bear in mind the possibility of AIP when the sudden onset of hyperglycemia together with enlargement of the pancreas are observed in subjects without a history of diabetes mellitus.