[Factitious hypoglycemia caused by taking a sulfonylurea drug]

Three cases of factitious (self-induced) hypoglycaemia, brought about by regular intake of sulphonylurea preparations, seen in the span of three years are reported. The clinical picture was similar to that caused by an insulinoma. One patient was a 31-year-old male nurse, another a 17-year-old girl whose mother was a diabetic, the third a 60-year-old female diabetic. The correct diagnosis of factitious hypoglycemia was made only after demonstrating glibenclamide in serum and urine. Factitious hypoglycemia can be differentiated from fasting hypoglycemia caused by hyperinsulinaemia by a lowered C-peptide level after injection of insulin. When sulphonylurea preparations are taken, the only way of distinguishing factitious hypoglycemia from insulinoma is by determining the drug in serum and urine. The cases reported in the literature are almost all in medical personnel, diabetics or members of their family.