Severe Uncontrolled Pancreatogenic Diabetes in a Patient With Prior Alcoholic Pancreatitis and Partial Pancreatectomy.

Pancreatogenic diabetes mellitus (type 3c diabetes mellitus, T3cDM) is an underrecognized form of secondary diabetes resulting from pancreatic exocrine disease, including chronic pancreatitis and pancreatic resection. It is frequently misclassified as type 2 diabetes mellitus, leading to delayed diagnosis and suboptimal management. We present a case of a 57-year-old female with a history of chronic alcoholic pancreatitis status post partial pancreatectomy who presented with severe uncontrolled hyperglycemia and medication nonadherence. Laboratory evaluation revealed a serum glucose of 668 mg/dL, hemoglobin A1c of 19%, and a low C-peptide level with normal insulin levels while receiving exogenous insulin, consistent with impaired endogenous insulin secretion and pancreatogenic diabetes. Despite repeated counseling and multiple attempts to optimize insulin therapy, the patient persistently refused insulin administration, resulting in refractory hyperglycemia throughout hospitalization. This case highlights the diagnostic challenges of distinguishing pancreatogenic diabetes from type 2 diabetes mellitus in patients with underlying pancreatic disease and emphasizes the importance of recognizing characteristic clinical features, including prior pancreatic injury and reduced endogenous insulin production. Early identification of T3cDM is essential because its pathophysiology and management differ substantially from type 2 diabetes mellitus and often require early insulin-based therapy to improve glycemic control and reduce long-term metabolic complications.