An unusual case of Insulin-Mediated Hypoglycaemia — ASN Events

An unusual case of Insulin-Mediated Hypoglycaemia (#350)

Nadia Patel 1 , Ross Cuneo 2
  1. Diabetes and Endocrinology, Greenslopes Private Hospital, Brisbane, QLD, Australia
  2. Diabetes and Endocrinology, Princess Alexandra Hospital, Brisbane, QLD, Australia

We describe the case of a 26 year old female who presented with 6 months of symptomatic reactive hypoglycaemia. She had intentionally lost 25kg in weight over the preceding 5 years through diet and exercise but had not undergone bariatric surgery. At 60 minutes after a mixed meal, plasma glucose fell to 2.0 mmol/L with insulin 6.1 mU/L and C-peptide 1.4 nmol/L, consistent with insulin-mediated reactive hypoglycaemia. Interestingly, a 72 hour fast was also positive with symptomatic hyperinsulinaemic hypoglycaemia developing after 29 hours with a plasma glucose of 2.1 mmol/L, insulin 5.0 mU/L, C-peptide 0.5 nmol/L and pro-insulin 17.9 pmol/L. Extensive pancreatic imaging failed to reveal a mass lesion but selective arterial calcium stimulation (SACS) testing localised abnormal beta cells to the proximal splenic artery territory with a four-fold rise in insulin levels from 8.2 mU/L at baseline to 36 mU/L at 60 seconds. Medical therapy with diazoxide was unsuccessful and she finally underwent a subtotal distal pancreatectomy. Histopathological examination of the resected pancreas was consistent with nesidioblastosis.

This is a case of Non-insulinoma Pancreatogenous Hypoglycaemia Syndrome (NIPHS) due to nesidioblastosis, a relatively uncommon but increasingly recognised condition accounting for 0.5 to 7% of cases of adult persistent hyperinsulinaemic hypoglycaemia. (1,2) NIPHS is described as postprandial (reactive) hypoglycaemia without evidence of an insulinoma but with histopathological features of islet cell hypertrophy or nesidioblastosis. (3,4) The cause of adult NIPHS has not been clearly established but there is an association with Roux-en-Y Gastric Bypass Surgery.  (5,6) Our case is unusual as the patient had both reactive and fasting hypoglycaemia, in addition to having a history of significant non-surgical weight loss. Furthermore, SACS testing clearly localised an abnormal area of pancreas even though diffuse pancreatic involvement is more expected.

The evaluation and management of this patient will be discussed in relation to the available literature.

  1. 1. Witteles et al 2001 Adult-Onset Nesidioblastosis Causing Hypoglycemia. Arch Surg 136(6):656-663
  2. 2. McElroy et al 2010 Case report: focal nesidioblastosis (“nesidioblastoma” ) in an adult. Human Pathology 41:447-451
  3. 3. Service et al 1999 Noninsulinoma pancreatogenous hypoglycaemia: a novel syndrome of hyperinsulinemic hypoglycaemia in adults independent of mutations in Kir6.2 and Sur1 genes. J Clin Endocrinol Metab 84:1582-9
  4. 4. Anlauf et al 2005 Persistent Hyperinsulinemic Hypoglycemia In 15 Adults with Diffuse Nesidioblastosis. Am J Surg Pathol 29(4)524-33
  5. 5. Service et al 2005 Hyperinsulineamic Hypoglycemia with Nesidioblastosis after Gastric-Bypass Surgery. NEJM 353:249-54
  6. 6. de Heide et al 2012 Functional Imaging in Hyperinsulinemic Hypoglycemia after Gastric Bypass Surgery for Morbid Obesity. J Clin Endocrinol Metab 97:E963-E967