Recurrent hypoglycaemia in a patient with thyrotoxicosis due to Insulin autoimmune syndrome

Abstract

Insulin autoimmune syndrome (IAS) is an immune-mediated hyperinsulinaemic hypoglycemia in individuals previously unexposed to exogenous insulin. A 63-year-old woman developed recurrent hypoglycemic episodes despite being on optimal glycemic support. She was diagnosed with Graves’ disease and was on carbimazole. Her insulin: C peptide ratio was suggestive of exogenous insulin administration or presence of insulin autoantibodies. Her insulin antibody level was elevated. IAS was probably secondary to her carbimazole therapy.

Keywords

• Hypoglycaemia
• Insulin autoimmune syndrome
• Hirata's disease
• Insulin autoantibodies
• Hyperinsulinism