Introduction: Prevalence of obesity is increasing worldwide. As a consequence the number of people undergoing bariatric surgery is also on the rise. Hypoglycaemia is increasingly seen in patients who have undergone gastric bypass surgery and we have successfully managed most of them. Here we describe our experience in dealing with one of the patients with disabling hypoglycaemia.
Case-report: A 35-year-old woman with BMI of 41.87 kg/m2 had Roux-en-Y gastric bypass. She lost six stones following her surgery but started to develop symptoms of hypoglycaemia after 15 months. She sustained several injuries during episodes of hypoglycaemia and had frequent hospital admissions for collapse. She was commenced on low glycaemic index food and several medications including acarbose, diazoxide followed by octreotide were tried. None of these measures helped resolve the disabling hypoglycaemia. She therefore had a battery of investigations including short synacthen test (SST), pituitary function tests, chromogranin A, 5-HIAA, anti-insulin antibody, insulin, C-peptide, IGF2: IGF1 ratio, Urinary sulfonylurea screen, Octreotide scan, MRI Pancreas and pituitary. Her insulin and C-peptide were inappropriately elevated. Rest of the investigation were within normal limits. Mixed meal test ruled out reactive hypoglycaemia. She had 68Ga DOTANOC whole body PET scan, which showed no evidence of somatostatin receptor positive disease. Insertion of a PEG tube to feed did not help. As a last resort, she had a laparoscopic reversal of her gastric bypass. She has not experienced any severe hypoglycaemic episodes following discharge.
Discussion: Managing hypoglycaemia following gastric bypass surgery can be challenging. Although dumping syndrome is a common cause, other causes like adrenal insufficiency and insulinoma should be considered. In our case the patient had marked increase in insulin and C-peptide, which might reflect an exaggerated response of carbohydrate intake. Reversal of bypass should be the last resort if disabling hypoglycaemia persists despite conservative management. Exendin 939, could be considered, when commercially available before considering reversal of bypass.
Conclusion: A systematic approach is needed when investigating and managing hypoglycaemia following bariatric surgery.