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Autoimmune Hypoglycaemia

المؤلف:  Wass, J. A. H., Arlt, W., & Semple, R. K. (Eds.).

المصدر:  Oxford Textbook of Endocrinology and Diabetes

الجزء والصفحة:  3rd edition , p1014

2026-08-29

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 Insulin autoimmune syndrome (IAS) is a rare disease which was first reported and is most prevalent in Japan, and is defined as endogenous hyperinsulinaemic hypoglycaemia associated with the presence of insulin autoantibodies (IAA) in patients without a prior history of insulin treatment. Sometimes it is associated with autoimmune diseases such as Graves’ disease or rheumatoid arthritis, or drugs containing a sulfhydryl group such as methimazole, carbimazole, penicillamine, tiopronin, and glutathione. The suggested mechanisms for hypoglycaemia in IAS are the release of free insulin from the large buffering reservoir of insulin- IAA complexes, which can dissociate unpredictably, and potentiation of insulin bioactivity. Symptoms usually occur in the late post- prandial rather than the fasting period because the initial binding of insulin to IAA after food ingestion further stimulates the secretion of free insulin, the insulin- IAA complexes then dissociate spontaneously several hours after eating to release more free insulin leading to hypoglycaemia. In patients with autoimmune disease, hypoglycaemia caused by autoantibodies against insulin receptors which activate insulin receptors regardless of circulating insulin concentrations have also been described. An increase in blood insulin with low C- peptide levels in these rare cases is probably related to the decrease in insulin clearance.

Insulin- IAA complexes often interfere with insulin assays to pro duce spuriously high insulin levels. Total insulin levels in IAS can be up to 100- fold higher than free insulin. Laboratory confirmation can be obtained by directly measuring IAA in the blood or using polyethylene glycol immunoprecipitation and gel filtration chromatography to confirm the presence of autoantibodies. In contrast to hyperinsulinaemia due to exogenous insulin or insulin receptor autoantibodies, the C- peptide level is not suppressed.

Treatment of IAS consists of small frequent meals with low con tents of simple sugars, discontinuation of culprit drugs, diazoxide, plasmapheresis, and corticosteroid therapy. Plasmapheresis removes IAA mechanically, whereas steroids decrease IAA production and alters their properties (binding and dissociation capacities). Most cases resolve spontaneously within one year but may recur if a culprit drug is re- administered.