Factitious hypoglycemia in a diabetic: Metabolic studies and diagnosis with radioactive isotopes

A case of “spontaneous hypoglycemia” in a diabetic, due to misuse of insulin, is described. Differentiation from insulinoma was difficult. Some of the anomalous results obtained during standard provocative tests are regarded in retrospect, as due to self-administration of exogenous insulin even though the patient was in hospital and apparently under strict supervision at the time of the tests. This may also explain some previously published reports with anomalous results. Distal pancreatectomy was carried out because of persistent unexplained hypoglycemia with temporary relief of symptoms but subsequent relapse. Correct diagnosis was made when an illicit store of insulin was discovered in the false bottom of a jewel box. This was labeled surreptitiously with 131I which was later demonstrated in the urine, blood, and at the site of injection. Though rare in diabetics, factitious hypoglycemia presents difficult problems in diagnosis.