Endocrine Abstracts

A 63-year-old gentleman presented with multiple episodes of unsteadiness of gait that had started over the preceding 1 week, associated with reduced consciousness. His medical background included TIA, hypertension and dyslipidaemia, taking clopidogrel, amlodipine and atorvastatin. He did not report any preceding illness, or any new medications. He was brought to the emergency department where examination was unremarkable, and so was his biochemistry. Neuroimaging and ECG were normal. Capillary blood sugar was 2.3 mmol/L coupled with low ketones. Despite being given glucose supplements, the low capillary blood glucose readings would recur, going as low as 1.4 mmol/l. His cortisol values, TFTs, and coeliac serology were unremarkable, HbA1c was 37 mmol/mol. Simultaneous serum insulin levels were found to be 4957 mU/l, C-peptide levels were 1759 pmol/l, and sulfonylurea screen was negative. Contrast CT of his abdomen was normal. EUS was undertaken to confidently rule out an insulinoma, and this was normal as well. He was empirically started on diazoxide and the panel of anti-insulin antibodies came back positive. The hypoglycemic episodes gradually started reducing, and he ultimately came off diazoxide after 7 months and remained normoglycemic thereafter. This case highlights an uncommon presentation of a rare condition, in the absence of any known trigger. Development of Hirata’s disease (Insulin Antibody Syndrome) involves the formation of insulin-IAA complexes. IAA prevent the binding of insulin to its receptor in the postprandial phase. Insulin is then released from the complexes, causing hypoglycemia. Drugs associated with IAS are mostly sulfhydryl-group drugs, which act as haptens. They interact with the disulphide bonds of insulin, potentiating its immunogenicity. Viral infections can be triggers for the development of IAS. Since IAS usually is a self-remitting disease, the management involves dietary modifications. Pharmacological therapy includes drugs that reduce pancreatic insulin secretion and immunosuppressive agents.