Hyperosmolar hyperglycemic coma in an infant with neonatal diabetes mellitus

Neonatal diabetes mellitus (NDM) is a rare disease distinct from type 1 diabetes mellitus (T1DM). While T1DM results from autoimmune destruction of pancreatic beta cells, NDM arises from genetic mutations to insulin production and secretion pathways. We present a case of an infant presenting to the emergency department with shock and poor responsiveness, found to have neonatal DM with hyperosmotic hyperglycemic syndrome (HHS). This report distinguishes NDM from T1DM, illustrating the subtle but clinically significant differences in pathophysiology and implications for initial management of NDM in the emergency department setting.