ABSTRACT
@EN A 36-year-old woman with Graves' disease developed spontaneous hypoglycemia after treatment for 4 weeks with methimazole. She experienced fainting episode a few times for 2 weeks. Although the patients had not received exogenous insulin,
significant
insulin-blinding antibodies were found in the serum, and a large amount of total & free insulin (810 and 150 μu/ml, respectively) and C-peptide reactivity (CPR, 8.0ng/ml) were detected in serum. After glucose loading, blood glucose and total
isulin
levels increased abnormally. The titers of insulin autoantibodies, elevated serum total & free insulin, and CPR levels decreased gradually, but insulin autoantibodies and elevated insulin levels were still present in the serum 9 months after the
episode
of hypoglycemia. These findings suggest that the patient's spontaneous hypoglycemia was due to excess free insulin released from antibody-bound insulin, and that methimazole might play a role in the initiation of production of insulin
autoantibodies.
Further studies are needed to resolve a possible role of coexisting islet cell stimulating antibodies (ICSTA) in this syndrome (J Kor Soc Endocrinol 8:451~455, 1993).
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