Category: Diabetes/Prediabetes/Hypoglycemia

Monitor: 6

6 - HYPOGLYCEMIA AFTER ILEAL RESECTION: POST-SURGICAL COMPLICATION OR INSULINOMA?

Saturday, Apr 27
11:00 AM – 11:30 AM

Objective :

To report a case of insulinoma after ileal resection.


Methods :

We describe a 68-year-old female with a history of partial ileal resection for ileitis in 1970s, who presented with on and off episodes of symptomatic hypoglycemia since the past three years. Recorded blood sugar readings were as low as 15mg/dl. She had no history of diabetes mellitus. Whipple’s triad was found to be positive. Further work-up showed normal/negative insulin, proinsulin, C-peptide levels, sulfonylurea screen, insulin receptor antibodies, IGF2, glucagon, cortisol. CT abdomen to look out for islet cell masses/hyperplasia was unremarkable. Patient’s symptoms were thought to be secondary to complication of ileal resection. She was advised to consume small, frequent meals.


Results :

Her symptoms initially improved but reappeared in one year. Mixed meal test showed pattern consistent with reactive hypoglycemia, with no evidence of fasting hypoglycemia. She was started on Acarbose with meals but continued to have more frequent episodes of hypoglycemia. On reassessment, her C-peptide (2.64ng/ml, N:0.81-3.85ng/ml) and insulin levels (21.60mU/ml, N: 3-25mU/l) were high normal in face of fasting hypoglycemia (35mg/dl). She was started on Prednisone and Diazoxide. Repeat CT abdomen showed 1.5 cm mass in the head of pancreas, concerning for insulinoma. Endoscopic ultrasound guided biopsy was negative for neuroendocrine or pancreatic cancer. She underwent Whipple’s surgery with pathology confirming well-differentiated neuroendocrine tumor grade-1. Her hypoglycemic episodes completely resolved after surgery.


Discussion :

Hypoglycemia is increasingly recognized as a complication of gastrointestinal(GI) surgery, but insulinoma maybe a rare cause of hypoglycemia in these patients. Review of the medical literature reveals a total of seven cases of insulinoma and one pancreatic neuroendocrine tumor reported in patients following various types of GI surgery. In all these cases, insulinoma was not initially considered as a likely diagnosis due to its rarity and predominance of non-fasting hypoglycemia in these patients. Most cases of insulinoma occur within 1-5 years of surgery, but a few cases presented >20 years after surgery. To our knowledge, this is the first case of insulinoma reported following ileal resection.


Conclusion :

While insulinoma is rare, it can occur following GI surgery. Patients presenting with hypoglycemia after GI surgery should undergo further endocrine evaluation to exclude insulinoma.

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Pallavi Pradeep

Resident Physician
Carle Foundation Hospital/University of Illinois Urbana-Champaign
Urbana, Illinois

Dr. Pallavi Pradeep is a PGY2 internal medicine resident at Carle Foundation Hospital/University of Illinois Urbana-Champaign. She also serves as a faculty for University of Illinois College of medicine and Carle-Illinois College of medicine. She went to medical school in Manipal University, India. Her previous research projects have been in Diabetic foot assessment and practices and nosocomial infections. She has an interest in Endocrinology and is currently involved in research projects related to Diabetes, Nutrition and Obesity.

Toufic Abdo

Attending Physician
Carle Foundation Hospital/University of Illinois Urbana-Champaign

Dr. Toufic Abdo, MD is an endocrinology, diabetes & metabolism specialist working as an attending physician at Carle Foundation Hospital in Champaign, IL. He graduated from Amer U Beirut in 1997, did his residency in Internal medicine at State University of New York (SUNY) at Buffalo, from 1998-2001. He also did his fellowship in Endocrinology at SUNY from 2008-09.

Pallavi Pradeep

Resident Physician
Carle Foundation Hospital/University of Illinois Urbana-Champaign
Urbana, Illinois

Dr. Pallavi Pradeep is a PGY2 internal medicine resident at Carle Foundation Hospital/University of Illinois Urbana-Champaign. She also serves as a faculty for University of Illinois College of medicine and Carle-Illinois College of medicine. She went to medical school in Manipal University, India. Her previous research projects have been in Diabetic foot assessment and practices and nosocomial infections. She has an interest in Endocrinology and is currently involved in research projects related to Diabetes, Nutrition and Obesity.