36 year old female, with type I diabetes from eight years old, underwent gastric bypass procedure for weight loss. After surgery, she could not manage any significant carbohydrate or fat intake. She suffered from steatorrhoea and lost more than 30kg in weight. Gastric emptying study showed relatively slow emptying for the first 70 minutes with complete emptying by four hours. CT showed no structural abnormalities with normal biochemical investigations except for low ferritin and HbA1c 8.2%. Her fasting basal measurements showed several episodes of hypoglycaemia.Insulin pump bolus was delayed 70 minutes and basal rates optimised until she had no fasting hypoglycaemia. Iron infusion corrected iron deficiency and pancreatic replacement reduced her diarrhoea. She was able to eat small meals and her weight loss ceased. HbA1c was 7.8% with no episodes of hypoglycaemia. Dumping syndrome continued to fluctuate in severity, associated with her emotional upset. Diazepam was offered and gave better sleep at night but was not taken in the day for fear of over sedation. Acarbose did not improve her dumping symptoms but Metformin twice-daily gave a beneficial response in controlling her dumping symptoms.
In summary a long standing type 1 diabetic underwent gastric bypass for weight loss. This led to severe symptoms of dumping syndrome, poor glycaemic control and malabsorption. Type 1 diabetes management was made more challenging beacuse of gut malfunction.Meticulous adjustment of insulin pump bolus and basal rates, use of metformin and correction of nutritional deficiencies, led to metabolic improvements and a substantially better quality of life. It is important to recognise gastrointestinal complications of bariatric surgery in type 1 as well as type 2 diabetes. Gastric emptying studies can reveal the diagnosis and guide the adjustment of insulin infusion rates. Nutritional deficiencies should be sought and corrected and patients require long term specialist follow up.