Background:

The use of continuous glucose monitoring (CGM) has traditionally been limited in the setting of hypoglycaemia given the reduced precision of sensor readings at low glucose levels. The development of new sensors and more sophisticated algorithms for assessing lower glucose levels allows for consideration of CGM in a broader clinical context. We present two examples of CGM applied as an aid to management in patients with non-diabetic hypoglycaemia.

Methods: Two patients underwent interstitial glucose monitoring with 72 hour CGM.

Case 1: A 26 year old female presented with increasing frequency of hypoglycaemic episodes on a background of nesidioblastosis diagnosed at age seven years. She’d been managed on diazoxide since then with control of fasting hypoglycaemia and prevention of hypoglycaemic seizures. Weeks of reduced oral intake following a laparoscopic cholecystectomy in 2012 resulted in significant weight loss and recurrence of her symptoms. CGM was performed to document breakthrough hypoglycaemia and to guide therapy modification.

Case Two: A 48 year old woman presented with hypoglycaemia twelve months following gastric bypass. Her license was cancelled after several hypoglycaemic seizures. A 72 hour fast showed no evidence of hyperinsulinism or hypoglycaemia. Given her symptoms were primarily post-prandial she then underwent CGM to monitor glucose levels on her usual high carbohydrate/fat diet, and again following introduction of acarbose to establish correction of her hypoglycaemia.

Results:

Case One: Despite years without symptoms and ongoing treatment, hypoglycaemia was shown on CGM - this corrected with increased diazoxide. CGM also highlighted glucose excursions above the target range - reinforcing the need for balancing hypoglycaemia correction with inducing hyperglycaemia in this patient.

Case Two: Hypoglycaemia (nadir of 2.4mmol/L) was demonstrated following meals high in carbohydrate and refined fat. Repeat CGM after introduction of acarbose and strict dietary modification confirmed resolution of the hypoglycaemia, allowing renewal of her license.

Conclusion: Hypoglycaemia is a feared metabolic disturbance, for its potential morbidity/mortality and the inconvenience and lifestyle modifications imposed on patients. The use of CGM here was instrumental in objectively documenting hypoglycaemia and establishing treatment efficacy. These cases highlight potential additional applications of CGM beyond traditional hyperglycaemic patients with diabetes.