Hypoglycemia Unawareness in Insulinoma Revealed with Flash Glucose Monitoring Systems

Abstract

Abstract:The delayed diagnosis of insulinoma remains a clinical issue. One of the main causes of such a delay is hypoglycemia unawareness. A 53-year-old woman fell unconscious during postprandial exercises. Flash glucose monitoring (FGM) systems revealed glucose profiles with fasting hypoglycemia, which facilitated the clinical diagnosis of insulinoma even though she was unaware of her hypoglycemia. The preoperative comparison of the blood glucose values provided by FGM with those obtained from capillary blood were consistent. Thus, FGM may have potential utility in revealing the presence of insulinoma-induced hypoglycemia.

Factory-calibrated continuous glucose monitoring and capillary blood glucose monitoring in a case with insulinoma: usefulness and possible pitfall under chronic hyperinsulinemic hypoglycemia

“…In the present case, the values of MARDs and Δ glucose were relatively larger than in the previously reported case [11], although the values were acceptable and there was no significant difference between the two cases ( Table 2). It is of note that these case-to-case comparisons might be affected by lot-to-lot variations of the fCGM sensors.…”

“…fCGM systems avoid frequent CBGbased calibrations because of their factory calibration [9,10]. Although we previously identified the possible utility of fCGM for detecting hypoglycemia unawareness and preventing severe hypoglycemia [11], the method not only facilitates the diagnosis of insulinoma but also is useful in monitoring therapeutic responses against hypoglycemia such as glucose load via a central venous catheter and oral diazoxide administration (Fig. 1a, b), which contributed to establishing the need for prompt surgery in the present case.…”

“…As the differences between fCGM and CBG values in the present case (Case 1) seemed relatively large, we added analyses of the mean absolute relative differences (MARDs) and absolute differences (Δ glucose) between fCGM (Freestyle Libre Pro) and CBG values in Case 1 in several different conditions including fasting, postmeal (2 hours after meals), hypoglycemia (defined as CBG values below 70 mg/dL), and others. These values were also retrospectively compared with the results in the previously reported insulinoma cases using fCGM or CBG at Kyoto University Hospital [11]. These procedures were approved by the ethical committee of Kyoto University Hospital (local identifier: R1789) and conducted in accordance with the Declaration of Helsinki.…”

“…These fCGM systems require no CBG-based calibration due to their factory calibration, and the Freestyle ® Libre allows realtime access to the patient's current glucose levels [9,10]. We previously reported a case in which these features of the Freestyle ® Libre contributed to avoiding episodes of hypoglycemia by detecting unnoticed hypoglycemia, thus improving the patient's health-related quality of life [11]. However, the accuracy of fCGM systems in the hypoglycemic range under chronic hyperinsulinemic hypoglycemia such as that found with insulinoma has not been fully examined [12,13].…”

Use of a Continuous Glucose Monitor for Preoperative Monitoring and Treatment of Hypoglycemia in a Case of Pancreatic Neuroendocrine Tumor

“…While finger-stick glucose monitoring has been the foundation of glucose monitoring and management of diabetes for decades, CGMs have become available in recent years and are powerful tools for insulin-dependent type 1 and type 2 diabetes mellitus patients who require more frequent monitoring as well as those at high risk for hypoglycemia. The utility of continuous glucose monitoring outside of diabetes mellitus cases has rarely been reported (6,7).…”