Endocrine Abstracts

The continuous glucose monitoring system (CGMS) have recently been developed for use in diabetes to provide comprehensive blood glucose data around the clock during normal activities. We have demonstrated for the first time that CGMS can assist in the management of 2 patients with confirmed insulinomas. We present 2 female patients (aged 41 and 35 years) with symptoms suggestive of hypoglycaemia. Both had biochemical evidence of insulinoma with hypoglycaemia, hyperinsulinaemia and raised C-peptide levels on prolonged fast. Sulphonylurea screen was negative. Localisation procedures included CT abdomen, octreotide scan, PET/ CT scan which were negative in both cases. Endoscopic ultrasound demonstrated a 1cm pancreatic lesion in patient 1but was negative in patient 2. Calcium stimulation studies were positive in this patient, with a 30-fold insulin rise in the territory of the splenic artery. Whilst awaiting surgery, recurrent hypoglycaemia remained the main management problem. Treatment with diazoxide and octreotide was commenced. CGMS was performed prior to medical thereapy and after stabilisation on each treatment. This showed evidence of unrecognised prolonged asymptomatic, nocturnal hypoglycaemia which allowed dose adjustment. Both patients became euglycaemic on long-acting somatostatin analogues whilst awaiting surgical intervention and nocturnal hypoglycaemia was confirmed to have resolved. Our cases demonstrate the successful use of CGMS in the management of insulinomas whilst undergoing pre-surgical localising procedures.