Hypoglycemia presents important diagnostic and therapeutic problems. Severe and repetitive hypoglycemic episodes in patients without treatment may be difficult to explain. Failure to identify factitious hypoglycemia may lead to laparatomy or pancreatectomy. Hypoglycemia factitia is assessed as a manifestation of Munchausen’s syndrome (1), which is characterized by factitious illness associated with hospital peregrination, mythomanic discourse that includes medical elements, and passivity and dependence at examinations. Munchausen’s syndrome was first described in relation to laparotomophilia migrans patients, whose stories were dramatic and untruthful.

Between January 1997 and 30 November 1999, we searched for the presence of a sulfonylurea-related oral hypoglycemic agent in 129 patients who had unexplained severe hypoglycemia. The patients were recruited from all over France during a 35-month period. To detect the presence of sulfonylurea, we developed a chromatographic liquid method with UV detection.

In 22 patients (17%), a second generation of the sulfonylurea oral hypoglycemic agent was detected: glibenclamide was detected in 19 patients, and gliclazide was detected in 3 patients. The study population comprised 13 women (mean age ± SD 40 ± 18 years) and 9 men (64 ± 11 years). The plasmatic concentrations are usually superior to the therapeutic ones, and in seven cases, they were five times more, with a maximum of 18 times the therapeutic degrees. All of these patients had only one hypoglycemic agent. Diagnosing the patients was difficult, because the patients remained on their medication during their hospitalization stay, which was aimed at identifying an etiology. The search for hypoglycemic agents is made through a surveillance of glycemia. In a 28-year-old patient, we identified glibenclamide concentrations of 338 μg/l at 1:00 p.m. (therapeutic concentration 25–50 μg/l), of 141 μg/l at 10:00 p.m., and of 211 μg/l at 2:00 a.m. over a 2-day period. Few patients have family members who require treatment with hypoglycemic medication, but interrogation is usually difficult. In most cases, an insulinoma was suggested and sometimes a pancreatectomy was planned.

This study is the first to be conducted in order to evaluate the impact of Munchausen’s syndrome on hypoglycemia.

Only a few cases of hypoglycemia factitia with oral hypoglycemic agent have been published (25), yet the lack of publications must not result in neglect and underevaluation of the risk. Hypoglycemia factitia with sulfonylurea should be considered in the differential diagnosis of insulinoma. They can be excluded only by analyzing the patients’ blood for sulfonylurea drugs.

The etiologic diagnosis of severe hypoglycemia is difficult. The hidden absorption of one or more hypoglycemic agents must be tracked.

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Address correspondence and reprint requests to Thierry Trenque, Centre Régional de Pharmacovigilance, Laboratoire de Pharmacologie Toxicologie, Hôpital Maison Blanche, 45 Rue Cognacq-Jay, 51092 Reims Cedex, France. E-mail: ttrenque@chu-reims.fr.