• Two patients with insulinomas had unusual glucose and insulin-secretory dynamics in response to prolonged fasting. In patient 1, low insulin values persisted throughout three separate supervised fasts without a steady rise in the insulin-glucose ratio. In patient 2, a rising insulin-glucose ratio during a fast returned to normal after a documented catecholamine surge following a transient hypoglycemic episode. While patient 1 had clearly elevated proinsulin values of 52% to 57%, patient 2 had a near-normal value of 23%. The diagnosis of an insulinoma can usually be made by obtaining simultaneous glucose and insulin values during a prolonged supervised fast. Rarely, however, anomalous results may be obtained during supervised fasts of patients with insulinoma, and a broader range of diagnostic tests will be required to establish the correct diagnosis.
(Arch Intern Med 1985;145:1861-1863)
Dons RF, Hodge J, Ginsberg BH, Brennan MF, Cryer PE, Kourides IA, Gorden P. Anomalous Glucose and Insulin Responses in Patients With InsulinomaCaveats for Diagnosis. Arch Intern Med. 1985;145(10):1861–1863. doi:10.1001/archinte.1985.00360100127021