Endocrine Abstracts

For the diagnosis of hyperinsulinemic hypoglycemia (HH), it is necessary that in symptomatic hypoglycemia in the fasting test the insulin/glucose ratio is >0.3, or that in spontaneous hypoglycemia there are C-peptide >0.6 nmol/l and insulin >3.0 mIU/ml. It is a well-known fact about the increasing frequency of hypoglycemia after bariatric surgery (estimated up to 30% of patients), mostly within the Dumping syndrome, but the frequency of occurrence of noninsulinoma pancreatogenous hypoglycemia (NIPHS) after gastrectomy is still unknown. A 55-year-old female patient was referred to an endocrinologist due to hypoglycemia with neuroglycopenia and a positive Whipple triad – minimal home-measured glycemia was 1.9 mmol/l. Malnutrition dominates among the physical findings, with a BMI of 15 kg/m². Namely, 4 years ago, she was operated on because of gastric carcinoma (gastrectomy, lymphadenectomy, omentectomy, and right-sided hemicolectomy have been done), and during her follow up there were no signs of recurrence of the disease and/or dissemination. During the endocrinology examination, daily hypoglycemias were in the range of 2.0-2.7 mmol/l, during which was observed significant insulinemia (24.4-50.9 mIU/l) and C-peptide (1.4-2.8 nmol/l), During 5h oral glucose tolerance test and mixed meal test, HH was recorded. Radiological diagnostics (CT, MRI) ruled out the existence of a focal lesion in the pancreas. The response of counterregulatory hormones in repeated spontaneous hypoglycemia was blunted, which is why an insulin tolerance test was performed: cortisol 86\..61\..100\..119\..99.9 nmol/l, PRL 377\..290\..227\..195\..180 mIU/l, HGH 0.5\..1.0\.. 2.5\..0.4\..0.5 mIU/l – showing hypopituitarism. MRI showed no focal changes in the sellar region, but there were two aneurysms of the internal carotid artery slightly compressing the pituitary. Throughout the examination, the patient used megestrol for appetite stimulation. After excluding megestrol, normal baseline values of stress hormones were verified, and an adequate spike of cortisol was recorded in the ACTH test. Despite compliance with the diet, HH continued. Trial therapy with fast-acting octreotide was accompanied by significant hyperglycemia, so it was replaced with diazoxide, and with a daily dose of 175 mg, a satisfactory therapeutic response was achieved. HH in gastrectomy patients is a rarity and the most of published literature is in the form of case reports. In our patient, we speculate that during the post-gastrectomy period, she developed functional gastrointestinal hormonal adaptation and secondary nesidioblastosis (NIPHS). Hypopituitarism in our patient was observed as a transient and described side effect of megestrol, but close monitoring was continued due to aneurysms in the sellar region.