# Medically Refractory Nesidioblastosis as a Late Adverse Effect of Roux-en-Y Gastric Bypass

## TL;DR

A man who had gastric bypass surgery years ago developed severe hypoglycemia due to a rare condition called nesidioblastosis, which was unresponsive to multiple treatments.

## Contribution

This case highlights nesidioblastosis as a late complication of Roux-en-Y gastric bypass and the challenges in managing medically refractory cases.

## Key findings

- The patient had profoundly elevated insulin and C-peptide levels with no evidence of insulinoma.
- Selective arterial calcium stimulation test confirmed nesidioblastosis.
- Medical therapies and dietary interventions failed to control hypoglycemia effectively.

## Abstract

A male in his late 40s with a past medical history of morbid obesity status post Roux-en-Y gastric bypass in 2004 presented to the emergency department with recurrent hypoglycemia. The hypoglycemic episodes were triggered by preceding hyperglycemia shortly after a meal. Due to the rapid drop in glucose, he often did not have sufficient time to ingest a rapid-acting carbohydrate snack, resulting in the progression of neuroglycopenic symptoms to syncope. His wife would then immediately administer intramuscular glucagon. A thorough workup did not reveal decompensated liver cirrhosis, chronic kidney disease, congestive heart failure, hypothyroidism, adrenal insufficiency, or insulin use. Serum insulin and C-peptide levels were profoundly elevated. A magnetic resonance imaging (MRI) of the abdomen and pelvis showed no pancreatic mass to suggest an insulinoma. He was referred to interventional radiology (IR) for a selective arterial calcium stimulation test (SACST), which showed an insulin ratio >2 in the gastroduodenal and hepatic arteries, consistent with a diagnosis of nesidioblastosis. He was trialed on numerous medications, which included octreotide, acarbose, diazoxide, and verapamil. He did not tolerate the octreotide due to the adverse effect of worsening abdominal pain and elevated serum lipase consistent with an attack of acute on chronic pancreatitis. The remaining medical regimen was ineffective at preventing hypoglycemia. Although evidence is lacking for use in this context, empagliflozin was then added to prevent the hyperglycemic spikes; however, this too proved ineffective at preventing hypoglycemic episodes. He underwent placement of a percutaneous endoscopic gastrostomy tube intended to tightly control his serum glucose via carbohydrate-low, protein-rich enteral feeds to prevent hyperglycemic episodes; however, this too failed due to suboptimal compliance with oral diet. Endocrinologic surgery declined distal pancreatectomy due to high morbidity and mortality risk with questionable benefit. The patient opted to seek a second opinion at another medical center.