[Sulfonylurea-induced factitious hypoglycemia]

3 patients with recurrent, symptomatic hypoglycemia associated with increased insulin and C-peptide blood levels are described. 2 men aged 37 and 21-years had mental and social problems and although they had access to sulfonylurea drugs, both denied intake. 1 was scheduled for pancreatectomy, but as a result of the vigilance of the surgeon, the operation was canceled. By demonstrating sulfonylurea in their urine, a definitive diagnosis of factitious hypoglycemia was established, and further invasive procedures were avoided. The third was a woman aged 40-years had malignant insulinoma with liver metastases, proven by cytology. The common and differentiating clinical and laboratory characteristics of hypoglycemia due to insulinoma and factitious hypoglycemia secondary to sulfonylurea intake are discussed, and the importance of urine analysis demonstrating the presence of sulfonylurea is emphasized.