Introduction: Gastric bypass surgery is performed for intractable severe reflux oesophagitis not amenable to vagotomy and pyloroplasty. Long-term complications include dumping syndrome, nutritional deficiencies, incisional hernia and weight loss. We report a case of unexplained adrenal insufficiency in a patient who had gastric bypass surgery.
Case: A 77-year-old gentleman presented with a history of recurrent hypoglycaemic episodes. Hypoglycaemic symptoms occurred on a daily basis over several years with capillary blood glucose readings ranging between 1.9 and 2.5 mmol/l during episodes. He was diagnosed with dumping syndrome following gastric bypass surgery 18 years when pyloroplasty and vagotomy had not worked for severe reflux oesophagitis. He had significant weight loss following that surgery. There was no history of diabetes or ingestion of any medication that could cause hypoglycaemia. He was taking adequate nutrition.
Investigations and Management: His random cortisol was 26 nmol/l and a subsequent Short Synacthen test showed an inadequate response (0-min cortisol of 25 nmol/l and 30-min cortisol of 156 nmol/l), adrenal antibodies were negative and serum adrenocorticotrophic hormone (ACTH) level was less than 5, indicating adrenal hypofunction secondary to ACTH failure. Other pituitary hormones and blood results (thyroid, liver, renal function) were normal. Pituitary MRI and adrenal CT were normal. He was commenced on hydrocortisone 20 mg a day and the frequency of hypoglycaemic episodes went down from once a day to once a month.
Discussion: The cause of adrenal insufficiency in this case remains unexplained. Possible mechanisms include malabsorption of bile, trace elements and essential vitamins resulting in reduced steroid synthesis, weight-loss-related re-setting of hypothalamopituitaryadrenal axis following drastic weight loss, and perioperative complication from blood loss resulting in pituitary apoplexy. This case emphasises the importance of endocrine surveillance as part of the long-term follow-up for patients after excessive weight loss post gastric surgery.