Endocrine Abstracts

Post-bariatric-surgery hypoglycaemia (PBH) typically presents at least six months post-operatively, particularly in those who have undergone Roux-en-Y gastric bypass (RYGB), with the literature suggesting that this condition develops in up to 30% of people post-bypass surgery. PBH is characterised by high postprandial insulin and glucagon-like peptide-1 secretion leading to hypoglycaemia 1-3 hours after consumption of meals that are high in carbohydrate content. We present the case of a 48-year-old female, who underwent RYGB in 2009, without prior history of diabetes (all previous HbA1 c results available since 2015 have been in the range of 33-41 mmol/mol). Seven years after RYGB, she first noticed hypoglycaemic events while monitoring during pregnancy, which were mostly asymptomatic. Over the last few years, she has increasingly been experiencing autonomic symptoms 1-2 hours after high-carbohydrate meals, with capillary glucose levels dropping as low as 2.5 mmol/l and symptoms improving after carbohydrate intake (Whipple’s triad). She does not report episodes of fasting hypoglycaemia, no other significant medical history other than vitiligo, sigmoid diverticulosis and previous cholecystectomy with subsequent bile acid malabsorption causing intermittent diarrhoea, and with alternative causes of hypoglycaemia excluded biochemically (normal cortisol and fasting glucose), a clinical diagnosis of PBH was made. She had a Freestyle Libre trial; during the fortnight, her time-below-range (<3.9 mmol/l) was 19%, but with a strict low-carbohydrate diet her glycaemic variability was reduced and her symptoms and frequency of hypoglycaemia improved. She was not keen to take acarbose and has tried to manage PBH with dietary modification as per dietitian advice. She follows a low glycaemic-index carbohydrate diet (30 grams for meals, 15 grams for snacks) paired with vegetables, protein and healthy fats, taken every 3-4 hours, but she still experiences autonomic symptoms in daily life, affecting her quality of life. She reports that during the period she used continuous-glucose-monitoring (CGM), she was more confident to modify her dietary choices to prevent postprandial hypoglycaemia, and would be keen to continue using CGM, but the challenge remains that its use in PBH has not been approved by regulatory authorities in the UK. The literature demonstrates that CGM can help patients with PBH detect impending hypoglycaemia, allowing them to adopt dietary modification and early treatment to prevent and reduce post-prandial hypoglycaemia. Although currently not NHS-funded for PBH, CGM could be considered as a treatment tool for PBH in clinical practice alongside dietetic intervention, and it may be particularly important for people experiencing disabling episodes of hypoglycaemia.