Obesity has emerged as a major global health issue1,2, and metabolic and obesity surgery (MOS) is the most effective treatment for sustained weight reduction and resolution of complications.3 Single anastomotic gastric bypass (SAGB) surgery involves the creation of a longer gastric pouch that is anastomosed to the jejunum, creating a single tension-free gastrojejunostomy for ingested food to bypass the duodenum, whilst the efferent limb of the gastrojejunostomy receives bile, pancreatic, and proximal intestinal secretions.4
A 47-year-old lady presented with diabetic ketoacidosis. She had undergone laparoscopic SAGB eight months prior for complicated obesity in the setting of a type 2 diabetes mellitus (DM) diagnosis. However, she had been re-classified as having type 1 DM six weeks prior to her presentation, with fasting hyperglycaemia, an undetectable C-peptide level and detectable islet cell antibodies. Persistence of her symptoms and mild ketosis despite aggressive fluid resuscitation and insulin-dextrose infusion prompted further investigations. Abdominal imaging demonstrated dilated jejunal bowel loops proximal to the gastro-jejunal anastomosis, with air fluid levels suggestive of a small bowel obstruction. A gastroscopy revealed a tight stricture approximately 20cm into the efferent limb, and laparoscopic assessment showed internal herniation of small bowel through the defect between the anti-rotation suture and the efferent limb. The suture was successfully released to relieve the obstruction.
Efferent loop syndrome is often caused by adhesions, internal hernias, or stenoses secondary to scarring from previous ulcerations.4,5 It has been rarely reported after SAGB, as the procedure obviates the need for a second anastomosis.4 However, internal hernias must be considered as a differential diagnosis in non-surgical presentations such as DKA among patients who have undergone SAGB. Symptoms that persist despite initiation of appropriate treatment in DKA in the setting of past MOS warrant urgent investigations and consideration of explorative laparoscopic assessment, even if radiological findings are unremarkable.