Differential Diagnosis between Endogenous and Exogenous Insulin-Induced Refractory Hypoglycemia in a Nondiabetic Patient

THIS report describes a nondiabetic patient who had rectal adenocarcinoma and who suffered an episode of acute hypoglycemia while receiving intravenous fluids containing glucose. Workup of the case required determination of whether the hypoglycemia was associated with the malignant disease or with hyperinsulinism. If hyperinsulinism had been the causative factor, it could have been a consequence of augmented endogenous insulin secretion or accidental injection of insulin. Laboratory studies distinguished directly and definitively among these possibilities. We concluded that NPH insulin had been inadvertently injected.Case ReportThe patient was a 67-year-old man with adenocarcinoma of the rectum. After radiotherapy, he . . .