Use of a continuous glucose monitor in the management of inoperable metastatic insulinoma: a case report.

Journal: Endocrine Practice : Official Journal Of The American College Of Endocrinology And The American Association Of Clinical Endocrinologists

Objective: To describe the successful use of a continuous glucose monitor in the management of a patient with inoperable metastatic insulinoma.

Methods: We present a case of inoperable recurrent metastatic insulinoma in which medical therapy failed to relieve symptoms of dangerous hypoglycemia. We describe how the use of a continuous glucose monitor has assisted in avoiding hypoglycemia and improving her quality of life.

Results: A 70-year-old woman with a history of recurrent surgically treated insulinoma presented with recurrent hypoglycemia secondary to multiple metastases in the liver. Diazoxide therapy decreased the frequency of symptoms, but she continued to have hypoglycemic episodes resulting in frequent visits to the emergency department. Since starting to use a continuous glucose monitor, she has been able to avoid hypoglycemia with associated neuroglycopenic symptoms. While the accuracy of the device was poor when compared with conventional fingerstick monitors, the sensor tended to read higher than the meter in the hypoglycemic range. Although this led to more frequent false-positive hypoglycemic alarms, true episodes of severe hypoglycemia were rare.

Conclusions: Malignant insulinomas are rare tumors. Many affected patients have disease that is unresectable, and medical therapy is limited in its ability to prevent hypoglycemic episodes. We have demonstrated that a continuous glucose monitor can be a useful adjunct to therapy to reduce hypoglycemic episodes by alerting the patient to low glucose concentrations before the development of neuroglycopenic symptoms.