title: Recurrent hypoglycemia from insulin autoimmune syndrome.
abstract: Insulin autoimmune syndrome (IAS) is an uncommon cause of hyperinsulinemic hypoglycemia characterized by autoantibodies to endogenous insulin in individuals without previous exposure to exogenous insulin. IAS is the third leading cause of spontaneous hypoglycemia in Japan, and is increasingly being recognized worldwide in non-Asian populations. We report a case of IAS in a Caucasian woman with recurrent complaints of hypoglycemia, with laboratory findings of serum glucose 2.5 mmol/L (45 mg/dL), insulin 54,930 pmol/L (7,909 μIU/mL), connecting peptide (C-peptide) 4,104 pmol/L (12.4 ng/mL), and a corresponding insulin to C-peptide molar ratio of 13.4 during a spontaneous hypoglycemic event. Autoantibodies to insulin were markedly elevated at > 50 kU/L (> 50 U/mL). IAS should be considered in the differential diagnosis of hypoglycemia in non-diabetic individuals. Distinction from insulinoma is especially crucial to prevent unwarranted invasive procedures and surgical interventions in hypoglycemic patients.
authors: Division of Medical Biochemistry, Department of Pathology and Laboratory Medicine, University of British Columbia, 855 West 12th Avenue, Vancouver, BC, V5Z 1M9, Canada, SWong6@providencehealth.bc.ca.
authors: Sophia L
authors: SL
authors: Wong
authors: Anne
authors: A
authors: Priestman
authors: Daniel T
authors: DT
authors: Holmes
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000150:complications* / Q000276:immunology; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology* / Q000276:immunology; D007330:Insulin Antibodies / Q000097:blood*; D008875:Middle Aged; D012008:Recurrence; D013577:Syndrome
chemical_list: D001323:Autoantibodies; D007330:Insulin Antibodies
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