Postprandial Hypoglycaemia following bariatric surgery;a case report

ABSTRACT

Introduction: Postprandial hypoglycaemia (PPH) is a recognised complication of gastric bypass surgery. We present a case where the effects of PPH had a significant effect on patient's life and caused a real challenge to the medical team. Case A 55 year old woman had a gastric bypass surgery in 2018 with subsequent drop in weight from 127kg to 78kg. 1 year following surgery she developed episodes of feeling unwell particularly after food with associated low blood glucose levels, 2-4 mmol/L on finger prick testing. There were no early morning symptoms;no history of loss of consciousness;and her weight was stable. As a result of the hypoglycaemia, she stopped driving and was unable to perform her job as an Advanced Nurse Practitioner. A 2-week freestyle Libre flash blood glucose monitoring confirmed mild episodes of hypoglycaemia, 3-4mmol/L, particularly after food. A mixed meal test showed fasting plasma glucose of 4.7mmol/L with a drop to 2.3mmol/L, 3 hours after the meal. Insulin and c-peptide levels at the time of hypoglycaemia were raised at 195pmol/L and 1761pmol/L, respectively;sulphonylurea screen was negative. A short synacthen test and thyroid function tests were normal. A dietary intervention including, eating small frequent meals;not drinking fluids with meals;and low carb, high protein, high fat diet had little benefit. She responded well to very low carbohydrate diet <50 grams/day but this was difficult to maintain long-term. She did not find Acarbose 50-100mg with meals or Diazoxide 50mg od useful and she was worried about side effects. She declined psychology input and she was not keen on revision bariatric surgery due to lack of guaranteed benefit. She was started on a trial of Liraglutide 1.2mg od 2 weeks ago. She remains off work and awaiting an assessment by occupational health with consideration of early retirement. She continues to feel not confident to drive despite the approval of the Driving and Vehicle Licensing Agency (DVLA). We agreed to arrange for a 72-hour fast when the Covid-19 situation is better, and to consider Somatostatin Analogue therapy if the trial with Liraglutide is not successful. Discussion: This case highlights the complexity of managing PPH in patients following bariatric surgery, which is compounded by the lack of effective treatment options. Our patient's unwillingness to consider the possibility of a psychological component to her problem may have also hindered her management, as her symptoms were far more severe than the degree of hypoglycaemia recorded, and both Acarbose and Diazoxide were possibly discontinued too early. This is further complicated by the lack of funding for long-term care for patients post bariatric surgery;in the UK National Health Service (NHS), this is only funded for 2 years. Conclusions: Postprandial hypoglycaemia is a serious problem that could significantly impact patient's quality of life. More research is needed into effective treatment for this condition. Bariatric surgery is not the end of the journey for people with obesity and some patients would require longterm follow up.