Insulin Autoimmune Syndrome: a rare cause of postprandial hypoglycemia

HLA Alleles Associate with Insulin Autoimmune Syndrome

In recent years, there have been hundreds of reports on insulin autoimmune syndrome (IAS) globally; however, fewer than a hundred patients have undergone genetic testing. Our objective is to examine the background of IAS and the variations in drugs that trigger it among patients who have been genetically tested, aiming to deepen our understanding of this condition. HLA Analysis of 68 cases showed that DR4 is predominant, especially in individuals of East Asian descent, notably in DRB1 *0406. Methimazole was the primary drug associated with IAS in these populations, while in Caucasian individuals, the emphasis was on DRB1 *0403, with lipoic acid being the common inducer. The key factor determining disease risk is the combination of chromosomal allele variations, with HLA class II allele DR4 positive patients showing a strong association with DQA1 *0301/DQB1 *0302.

Uncommon triggers of insulin autoimmune syndrome: a case report

BACKGROUND

Insulin autoantibody syndrome (IAS), or Hirata disease, is caused by high concentrations of insulin autoantibodies, which result in spontaneous, mainly post-prandial, hypoglycemic episodes. We report a case of a previously healthy 67-year-old man presenting with recurrent fasting hypoglycemia culminating in a diagnosis of insulin autoimmune syndrome linked to omeprazole and probably spices, namely, coriander, and ginger.

CASE PRESENTATION

A previously healthy 67-year-old Sinhalese man presented with recurrent syncopal attacks for 3 months, which were found to be hypoglycemic episodes. He experienced mainly fasting hypoglycemic attacks, at a frequency gradually increasing to daily attacks. His cardiovascular, respiratory, abdominal, and neurologic examinations were normal. He was found to have insulin levels > 6000 mU/L and a post-polyethylene glycol insulin recovery of less than 9.5%. Contrast-enhanced computed tomography of the pancreas was normal. The diagnosis of insulin autoantibody syndrome was confirmed by testing for the insulin autoantibody level, yielding a level of > 300 U/mL. With regard to a possible trigger, he had a history of omeprazole intake for 2 weeks, 4 weeks prior to the onset of symptoms. He also consumed an herbal supplement containing coriander and ginger extracts daily for a period of 1 year, approximately 2 years prior to the onset of hypoglycemic attacks. He was commenced on prednisolone 30 mg daily, and hypoglycemic episodes responded dramatically, and thus he was tapered off corticosteroids.

CONCLUSION

Omeprazole-induced insulin autoantibody syndrome is likely in this patient; however, the known hypoglycemic effects of coriander and ginger make it worthwhile to consider a possible association with insulin autoantibody syndrome. In addition, this case report highlights the need to consider insulin autoantibody syndrome even in patients presenting with fasting hypoglycemic attacks.

Insulin autoimmune syndrome

SUMMARY

Insulin autoimmune syndrome (Hirata's disease) is a disorder caused by development of autoantibodies to insulin and manifested by hypoglycaemic syndrome. The overwhelming majority of physicians do not include it in the differential diagnosis of hypoglycaemic states because of a misconception of an extremely low prevalence of this condition. This results in unnecessary drug therapy and unjustified surgical interventions in patients that otherwise would be successfully treated conservatively. This disease is strongly associated with certain alleles of the HLA gene. In most cases, this condition develops in predisposed individuals taking drugs containing sulfhydryl groups. Formation of autoantibodies to insulin may be observed in patients with other autoimmune disorders, as well as in those with multiple myeloma or monoclonal gammopathy of undetermined significance. This paper presents the first Russian case report of insulin autoimmune syndrome in an adult patient.

LEARNING POINTS

Insulin autoimmune syndrome, Hirata's disease, anti-insulin antibodies, and hypoglycaemia.

Insulin Autoimmune Syndrome (Hirata Disease): A Comprehensive Review Fifty Years After Its First Description

Insulin autoimmune syndrome (IAS), also named Hirata's disease, is a rare condition characterized by hypoglycemic episodes due to the presence of high titers of insulin autoantibodies (IAA). IAS is a form of immune-mediated hypoglycemia, which develops when a triggering factor (ie, a medication or a viral infection) acts on an underlying predisposing genetic background. IAS pathogenesis involves the formation of insulin-IAA complexes that induce glycemic alterations with a double-phase mechanism: IAA prevent insulin to bind its receptor in the postprandial phase, possibly resulting in mild hyperglycemia; thereafter, insulin is released from the complexes irrespective of blood glucose concentrations, thus inducing hypoglycemia. The diagnosis of IAS is challenging, requiring a careful workup aimed at excluding other causes of hyperinsulinemic hypoglycemia. The gold standard for the definitive diagnosis is the finding of IAA in a blood sample. Because IAS is frequently a self-remitting disease, its management mostly consists of supportive measures, such as dietary modifications, aimed at preventing the development of hypoglycemia. Pharmacological therapies may occasionally be necessary for patients presenting with severe manifestations of IAS. Available therapies may include drugs that reduce pancreatic insulin secretion (somatostatin analogues and diazoxide, for instance) and immunosuppressive agents (glucocorticoids, azathioprine and rituximab). The purpose of this review is to provide a comprehensive analysis of the disease, by describing the burden of knowledge that has been obtained in the 50 years following its first description, took in 1970, and by highlighting the points that are still unclear in its pathogenesis and management.

Insulin autoimmune syndrome induced by exogenous insulin injection: a four-case series

BACKGROUND

Insulin autoimmune syndrome (IAS) is a rare cause of hypoglycemia and is characterized by the presence of insulin autoantibodies. Patients with IAS usually complain of hypoglycemia without any previous insulin received. Glucocorticoids and immunosuppressants are used to treat IAS.

CASE PRESENTATION

We report four patients with diabetes who were diagnosed with non-classical IAS and describe the treatment of these patients. Moreover, the differential diagnosis with hyperinsulinism is discussed.

CONCLUSION

High levels of insulin autoantibodies, as well as hyperinsulinemic hypoglycemia, are found in patients with diabetes mellitus and prior exogenous insulin exposure. This situation that we classified as non-classical IAS should be attached importance to.

Recurrent hypoglycemia, a rare case of insulin autoimmune syndrome in a young African American male

Insulin autoimmune syndrome (IAS) is an uncommon cause of spontaneous hypoglycemia from hyperinsulinemia due to autoantibodies against endogenous insulin (Jian-Ping Chu, 2016). These individuals have no prior exposure to exogenous insulin. We report a case of a 35-year-old African American male, who presented to Vaughn Regional Medical Center in Selma, AL, after he was found to have seizures from hypoglycemia, with a blood sugar of 63 on presentation. He was never diagnosed with diabetes in the past, nor did he have a history of seizure disorder. He continued to be hypoglycemic during the initial period of his hospital stay. His fasting insulin level was 27 mIU/l (normal is less than 25, with presence of insulin autoantibodies (IAA), and a negative workup otherwise. This led us to include IAS as one of our differentials for his hypoglycemia.

Autoimmune hypoglycaemia caused by alpha-lipoic acid: a rare condition in Caucasian patients

Insulin autoimmune syndrome (IAS), a rare cause of autoimmune hyperinsulinaemic hypoglycaemia, is relatively well known in Japan. The incidence in Caucasians is less than one-fifth of that reported in Japanese people, but it is becoming increasingly recognised worldwide in non-Asians as well. Drugs containing sulphydryl groups are known to be associated with the disease in genetically predisposed individuals. Moreover, several recent reports showed a direct association between the onset of IAS and the consumption of dietary supplements containing alpha-lipoic acid (LA). Insulinoma remains the most prevalent cause of hypersulinaemic hypoglycaemia in Caucasians. Consequently, primary investigation in these patients is generally focused on localisation of the pancreatic tumour, often with invasive procedures followed by surgery. We described a case of an Italian woman presenting to us with severe recurrent hypoglycaemia associated with high insulin and C-peptide levels and no evidence of pancreatic lesions at imaging diagnostic procedures. She had taken LA until 2 weeks before hospitalisation. After an evaluation of her drug history, an autoimmune form of hypoglycaemia was suspected and the titre of insulin autoantibodies was found to be markedly elevated. This allowed us to diagnose LA-related IAS, thus preventing any unnecessary surgery and avoiding invasive diagnostic interventions. Learning points: IAS is a rare cause of hyperinsulinaemic hypoglycaemia that typically affects Asian population, but it has been increasingly recognised in Caucasian patients. It should be considered among the differential diagnosis of hyperinsulinaemic hypoglycaemia to avoid unnecessary diagnostic investigations and surgery. It should be suspected in the presence of very high serum insulin levels (100-10 000 μU/mL) associated with high C-peptide levels. There is a strong association with administration of drugs containing sulphydryl groups included LA, a dietary supplement commonly used in Western countries to treat peripheral neuropathy.

Rare Cause of Recurrent Hypoglycemia: Insulin Autoimmune Syndrome

We report a case of insulin autoimmune syndrome associated with several autoantibodies, presenting with recurrent hypoglycemia, predominantly in the postprandial period, which improved by dietary management and spontaneously resolved within two months. Differentiation from other causes of hyperinsulinemic hypoglycemia, such as insulinoma, is important to avoid unnecessary invasive procedures or surgical interventions. The 75-gram oral glucose tolerance test (OGTT) and mixed meal test showed a typical pattern, which may be useful indirect evidence of insulin autoimmune syndrome.