Endocrine Abstracts

Insulin antibodies were common when animal insulin was used given its high immunogenicity. The advent of recombinant DNA technology in insulin production has reduced the incidence of insulin antibodies and its presence is rarely considered clinically significant. Exogenous Insulin Antibody Syndrome (EIAS) describes the formation of insulin antibodies to exogenous insulin. We present a case of a 65-year-old gentleman who was diagnosed with diabetes mellitus secondary to pancreatectomy for acute pancreatitis twenty years prior. His insulin requirement reached 3.2 units/ kg eighteen years into his diagnosis, on insulin detemir, novorapid and metformin. Due to the large volume of insulin per injection, insulin detemir was switched to equivalent dose of Insulin glargine. He was admitted to the hospital with severe hypoglycaemia two weeks later, necessitating insulin dose reduction to 1.3 units/kg. He was tested for antibodies specific for detemir and antibodies to human insulin. The results showed a very high amount of antibodies specific for insulin detemir at 41.9%. The high titre of insulin detemir-specific antibodies reduced insulin activity by competing for the insulin receptor, hence reducing insulin action and triggering hyperglycaemia and insulin resistance; a high affinity/low-capacity phenomenon. The absence of antibodies to insulin glargine in this patient’s case resulted in hypoglycaemia with equivalent dose. This case demonstrated a case of antibodies specific for detemir resulting in severe insulin resistance in pancreatectomy-related DM. Albeit rare, EIAS should be considered a differential diagnosis in patients with suboptimal glycaemic control and severe insulin resistance.