Endocrine Abstracts

Introduction: Insulin autoimmune syndrome (IAS) is characterized by the development of hypoglycemia due to insulin and insulin autoantibodies (IAA) interaction. The disease has a strong association with certain alleles of HLA gene. In most cases the disease affects predisposed persons who take drugs containing the sulfhydryl groups. The IAA are also noticed in patients with other autoimmune pathology and in patients with multiple myeloma or monoclonal gammopathy. In case of mild course of disease the treatment is not necessary, but in some cases the glucocorticoids may be prescribed.

Clinical case: A 46-year-old female patient with obesity (BMI 36.0 kg/m²) received the Thioctic acid since November 2017. Since December 2017 the patient had the episodes of dizziness and feelings of fear which occurred 2–3 hours after meals and accompanied by hypoglycemia to 2.1 mmol/l. The drug was discontinued. The results of examination in a non-specialized clinic: HbA1c 5.4%, insulin >600 mIU/l. Abdominal ultrasound and MRI did not reveal insulinoma. Since February 2018 no hypoglycemic episode appeared. In April 2018 the patient was firstly examined in Endocrinology Research Centre. During the 72-hour fast, mixed meal test and oral glucose tolerance test the normoglycemia was recorded according to the continuous glucose monitoring system. The results of examination: insulin 330.7 mIU/l, C-peptide 4.96 ng/ml, glucose 5.2 mmol/l, HOMA-IR 76, IAA 102.4 U/ml, antibodies (AB) to insulin receptor 4.156 ng/ml, AB to 21-hydroxylase, thyroid peroxidase, thyroglobulin, receptor for thyroid-stimulating hormone, glutamate decarboxylase, islet cell AB, islet antigen 2 AB, zinc transporter 8 AB were not increased. The electrophoresis and immunochemical study of serum and urine proteins did not reveal any pathologic findings. HLA-typing was carried out: DRB1: 03, 04; DQA1: 0301, 0501; DQB1: 02, 0302. There were no other autoimmune pathology in patient or any autoimmune pathology in her relatives. We diagnosed the IAS, induced by Thioctic acid. The examination in November 2018 revealed: insulin 143.1 mIU/l, C-peptide 4.91 ng/ml, glucose 4.87 mmol/l, IAA 35.26 U/ml, AB to insulin receptor 3.821 ng/ml. Thus, after discontinuation of Thioctic acid the levels of insulin and IAA gradually decreased, hypoglycemia was not recorded.

Conclusion: IAS should be excluded in any patient with hyperinsulinemic hypoglycemia to determine the appropriate tactics for subsequent examination and treatment. Imaging study of the pancreas is not required for patients with IAS. The detailed survey on the use of drugs and a thorough analysis of laboratory examination data are necessary.

Funding: The work was supported by the Russian Science Foundation (grant 17-75-30035).