Introduction: Previously referred to as late dumping syndrome, post-bariatric hypoglycemia (PBH) is thought to represent at least 1% of all hospitalizations for hypoglycemia and 10% of all clinically recognized hypoglycemia cases. However, through the advent of CGM and more strict criteria over the last decade these numbers are likely an underestimate. As obesity continues to remain prevalent and with rising bariatric centers to help deal with this epidemic, endocrinologists will play an increasing role in managing PBH patients.
Clinical Case: A 39-year female with a PMH of hypothyroidism and bariatric surgery (BS) in 2009 presented to our ER for a seizure. She has been having seizures nearly every 2 weeks for one year. Neurology started her on Keppra; however, no etiology was identified. EMS had documented a blood glucose of 40 mg/dL; the patient was given an amp of D50 with resolution of neuroglycopenic symptoms. TSH and cortisol levels were within normal range. A sulfonylurea panel in the ED was negative. The patient states the symptoms can occur while fasting but also mainly post-prandial. A 72-hr fast was conducted with the patient nadir POC glucose of 77. Subsequently, the patient had a mixed meal tolerance performed and after 2 hours had a seizure and was found to have a BG of 50 mg/dL with an insulin level of 49 uIU/mL and a c-peptide of 18.8 ng/mL. The patient was diagnosed with PBH, and was discharged with a CGM, started on acarbose and was seen by nutrition to discuss dietary modifications. She is now seen in our clinic with control of her symptoms with the addition of diazoxide.
Conclusion: Altered anatomy after bariatric surgery, particularly after gastric bypass and sleeve gastrectomy is thought to play a major role in developing PBH. By bypassing normal anatomy, gastric emptying is increased 2–3 x, which leads to a higher and more rapid appearance of glucose in the distal foregut. This subsequently leads to an amplified incretin response leading to a hyperinsulinemic response in patients who have had bariatric surgery; however, for unclear reasons some patients develop an even more amplified hyperinsulinemic response that leads to subsequent hypoglycemia. History of neuroglycopenic symptoms 1–3 hours after eating in a patient who had a gastric bypass > 6–12 months and with relief of symptoms with carbohydrates should raise an endocrinologist’s suspicion of PBH. Fasting hypoglycemia is an atypical feature that should raise one’s suspicion of a broader differential. Altered nutrition habits is the cornerstone of therapy with which the primary aim is to reduce post-prandial glucose spikes in these patients after they eat carbohydrates. These spikes in turn lead to hyperinsulinism leading to subsequent hypoglycemia. Primary diet modifications include controlled carbohydrate consumption of less than 30g per meal, avoiding high glycemic carbs, and always taking in ample fat and proteins with every meal.