[Autoimmune hypoglycemia: the fault of pyritinol?]

Initially reported in Japan, autoimmune hypoglycemia is related to the presence of insulin-binding antibodies, even in patients who have never been treated with insulin. The authors report a case of spontaneous autoimmune hypoglycemia in a French woman receiving pyritinol. The difference between insulin and C peptide radioimmunoassay levels prompted a search for insulin antibodies. In vitro studies confirmed their presence and showed that they were immunoglobulins G with two binding sites without species specificity. The outcome of autoimmune hypoglycemia is usually favourable, with a rapid decrease of insulin antibodies but steroid therapy is needed when serious clinical manifestations are present. The differential diagnosis with factitious hypoglycemia may be difficult. The reasons for the appearance of the insulin antibodies and the exact mechanisms of hypoglycemia remain hypothetical. However, drugs with a sulfhydril group, such as pyritinol, could play a causative role in this syndrome.