LATE POSTPRANDIAL HYPOGLYCEMIA AS THE SOLE PRESENTING FEATURE OF SECRETING PANCREATIC BETA-CELL ADENOMA IN A SUBTOTALLY GASTRECTOMIZED PATIENT

In this paper we describe for the first time late post-prandial hypogl ycaemia as the sole presenting feature of an insulinoma in a patient w ho had previously undergone subtotal gastrectomy. The symptoms of hypo glycaemia always occurred 1-3 h after meals, not in the fasting state. Because of the history of gastrectomy and because post-prandial hypog lycaemia was reproduced by an oral glucose tolerance test, the diagnos is of reactive hypoglycaemia was made. Eighteen months later a fasting test was performed: venous plasma glucose decreased from 3.8 mmol/l t o 2.7 mmol/l between 14 and 20 h of fast while plasma immunoreactive i nsulin did not decrease and plateaued at 185 pmol/l. Plasma C-peptide (0.9 nmol/l) and proinsulin (70 pmol/l, split 64, 65) were also elevat ed. All islet hormones increased in response to i.v. glucose and were suppressed after diazoxide. Although pre-operative procedures were neg ative in localizing an insulinoma, the patient underwent an operation and an insulinoma was detected at the body level of the pancreas. Thus , insulinoma should be considered in the differential diagnosis of rea ctive hypoglycaemia in gastrectomized patients. Response of islet horm ones to glucose and their suppression by diazoxide are evidence of a s ecreting insulinoma even in the absence of preoperative localization o f the pancreatic adenoma.