PSUN237 Hirata's Disease: A rare case of IAS in An African-American

Abstract

Abstract Background Endogenous insulin autoimmune syndrome (IAS), also known as Hirata's disease, is a rare condition characterized by hypoglycemic episodes due to the presence of high titers of insulin autoantibodies. It is a form of immune-mediated hypoglycemia and can be induced with certain medications or vital infection. Often misdiagnosed or late diagnosis after extensive workup. IAS is more prevalent in people of Asian heritage, more specifically Japanese individuals, and rarely seen in Caucasians. We present a case of IAS in an African-American man.Clinical case: 51 years old African-American man with high blood pressure and marijuana use presented to the Emergency Department after a syncopal episode. He stated to have recurrent episodes of fatigue, lightheadedness, blurred vision and diaphoresis mostly within 4-5 hours post-prandial or early morning and improved with food intake. He was not taking any medication or supplementation which can cause hypoglycemia. He was found to be tachycardic with blood glucose of 25 mg/dl, treated with IV dextrose and admitted with hypoglycemia. Endocrinology service recommended to obtain insulin, c-peptide, proinsulin, hydroxybutyrate, screen for oral hypoglycemic agents during hypoglycemic episode. His blood glucose decreased to 27 mg/dL within 6 hours of fasting and work-up was completed. Significant laboratory data revealed; insulin 1000 μIU/ml (2.6-24.9), c-peptide 7 ng/dL (1.1 - 4.4), proinsulin 229.7 mmol/L (0.0-10.0), beta hydroxybutyrate acid 0.09 mmol/L (0.02-0.27), insulin receptor antibody 173 nU/ml (<95), screen of hypoglycemic agent Negative. Conclusion The pathogenesis of IAS has not been fully understood. Interaction of a genetic predisposition with environmental triggers leads to the production of insulin autoantibodies. Incidence of IAS is higher in Asia compared to the western countries. Medications (methimazole, alpha-lipoic acid) and viral infections (measles, mump, rubella, varicella, coxsackie, HCV) are shown to trigger the development of IAS. Although rare, IAS should be suspected in any patient presenting with hypoglycemia in order to avoid any unnecessary diagnostic and therapeutic procedure. Patients with IAS has extremely high insulin concentrations, often above 170 μIU/ml which is a rare finding in other forms of endogenous hyperinsulinemic hypoglycemia. The measurement of insulin autoantibodies is mandatory for the diagnosis of IAS since it is the only lab test that allows a reliable diagnosis. Once confirmed, the patients should be evaluated carefully in order to assess the indication to pharmacologic therapy however no study have currently compared different treatment regimens. No data regarding its survival rate are currently available. Initial clinical suspicion of IAS can avoid unnecessary costs associated with imaging examinations and/or invasive surgical procedures.