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October 1985

Anomalous Glucose and Insulin Responses in Patients With Insulinoma: Caveats for Diagnosis

Author Affiliations

From the Diabetes Branch, National Institute of Arthritis, Diabetes, Digestive, and Kidney Diseases, Bethesda, Md. Drs Dons and Hodge are now with the Department of Internal Medicine, the Naval Hospital, Bethesda, Md; Dr Ginsberg, the Department of Internal Medicine, the University of Iowa School of Medicine, Iowa City; Drs Brennan (Gastric and Mixed Tumor Service) and Kourides (Endocrine Service), Memorial Sloan-Kettering Cancer Center, New York; and Dr Cryer, the Department of Internal Medicine, Washington University School of Medicine, St Louis.

Arch Intern Med. 1985;145(10):1861-1863. doi:10.1001/archinte.1985.00360100127021

• 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)

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