Nesidioblastosis is a glucose metabolism disorder characterized by profound hypoglycemia and inappropriate secretion of insulin. Treatment with diazoxide or somatostatin analogue is the first line of therapy. However, intervention such as pancreatectomy may be indicated in severe medically resistant cases. The incidence of diabetes increases with age and it correlates with the extent of surgical resection. However, there is only one case report of occurrence of overt diabetes in medically treated patients. We present a case of hyperglycemia in an adult with a previous diagnosis of nesidioblastosis.
56 year old male with intellectual disability secondary to cerebral palsy presented with a generalized tonic clonic seizure and was found to be hypoglycemic with a plasma glucose of 1.9 mmol/L (3.0-7.7) and a corresponding insulin level of 54.5 mU/L (<15.0), c- peptide 1.6 nmol/L (0.30-1.30). He had persistent hypoglycaemia which required intravenous 10% dextrose infusion. A 72 hour fast was discontinued when serum glucose was 1.9 mmol within 5 hours of commencing the fast with a corresponding c- peptide of 0.78 nmol/L (0.30-1.30), insulin 28.1 mU/L(<15.0), proinsulin 26.0 pmol/L (<13.3). A serum sulphonyluria screen was negative. His serum cortisol was 442 nmol/L and growth hormone was 5.6 mU/L (0.1-12.0).
Localisation studies failed to show evidence of insulinoma, a calcium stimulation test showed a diffuse rise in the insulin levels in all samples surrounding the pancreas, in keeping with a diagnosis of nesidioblastosis. He was treated with frequent feeding supplemented with complex carbohydrates and commenced on diazoxide 200 mg TDs as well as dexamethasone. He also required Octreotide injections. Over the course of time, he had recurrent hypoglycemic episodes despite regular diazoxide therapy. Seven months after the diagnosis of nesidioblastosis, he presented with hyperglycemia and reduced oral intake. His blood glucose ranged from 18-30 mmol/L (3.0-7.7), a corresponding low insulin 4.2 mU/L (<15.0) and a c-peptide of 0.35 nmol/L (0.30-1.30). He was discharged on novomix 30 44 units mane and 10 units with dinner.