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

Levels of anti-insulin antibodies in diabetic retinopathy patients: an observational cross-sectional study

Aim: This study evaluated the levels of anti-insulin antibodies (AIAs) and the influence of some antidiabetic medications on AIA in diabetes mellitus (DM) patients with retinopathy. Patient & methods: An observational cross-sectional study. Results: A lower titer of AIA IgG was observed in the diabetic retinopathy (DR) and DM-only study categories compared with the control group [DR = 86 (5-560), DM-only = 50 (5-500), versus control = 200 (7-565); p = 0.017]. Taking nifedipine and metformin were negatively correlated (r = -0.32, p = 0.04) with the levels of AIA IgE in the DR group. Conclusion: A decreased titer of circulating AIAs was observed in the DR study category, suggesting that AIA may not contribute to the pathogenesis of DR.

A Case of Acromegaly With Progressed Diabetic Retinopathy and Sarcopenia Diagnosed Following the Onset of Severe Hypoglycemia

Acromegaly is a rare disorder characterized by excessive production of growth hormone (GH) from a pituitary tumor, typically leading to elevated glucose levels due to increased insulin resistance; hypoglycemia is rare. However, the long-term effect of excess GH on the peripheral organs is still unclear. Here we present a 69-year-old man evaluated for the cause of a hypoglycemic episode. He was underweight (body mass index: 17.3 kg/m2) with sarcopenia, which potentially contributed to his hypoglycemia. Notably, he exhibited progressed proliferative diabetic retinopathy compared to other microvascular complications, leading to further endocrinological investigation. As a result, he was diagnosed with acromegaly showing elevated GH and insulin-like growth factor-1 (IGF-1) with a pituitary tumor. Opting against transsphenoidal surgery (TSS), the patient was treated with a somatostatin analog (SSA), achieving normalized IGF-1 levels with a monthly 120 mg lanreotide injection. In this case, acromegaly could lead to sarcopenia from GH-derived gluconeogenesis in the peripheral organs such as the reduction of muscle leading to reduced glucose reserves. Acromegaly in the elderly may present atypicality. Clinicians should be vigilant for unique manifestations such as advanced diabetic retinopathy, even in elderly patients with hypoglycemia.

Exogenous insulin autoimmune syndrome: A case report and review of literature

BACKGROUND

Insulin autoimmune syndrome (IAS) is a severe manifestation of spontaneous hypoglycemia. It is characterized by elevated levels of immune-reactive insulin and highly potent insulin autoantibodies (IAAs), which are induced by endogenous insulin circulating in the bloodstream. It is distinguished by recurring instances of spontaneous hypoglycemia, the presence of IAA within the body, a substantial elevation in serum insulin levels, and an absence of prior exogenous insulin administration. Nevertheless, recent studies show that both conventional insulin and its analogs can induce IAS episodes, giving rise to the notion of non-classical IAS. Therefore, more attention should be paid to these diseases.

CASE SUMMARY

In this case report, we present a rare case of non-classical IAS in an 83-year-old male patient who present with symptoms of a psychiatric disorder. Upon symptom onset, the patient exhibited Whipple's triad (including hypoglycemia, blood glucose level less than 2.8 mmol/L during onset, and rapid relief of hypoglycemic symptoms after glucose administration). Concurrently, his serum insulin level was significantly elevated, which contradicted his C-peptide levels. After a comprehensive examination, the patient was diagnosed with exogenous insulin autoimmune syndrome. Considering that the patient had type 2 diabetes mellitus and a history of exogenous insulin use before disease onset, it was presumed that non classical IAS was induced by this condition. The PubMed database was used to search for previous cases of IAS and non-classical IAS to analyze their characteristics and treatment approaches.

CONCLUSION

The occurrence of non-classical IAS is associated with exogenous insulin or its analogs, as well as with sulfhydryl drugs. Symptoms can be effectively alleviated through the discontinuation of relevant medications, administration of hormones or immunosuppressants, plasma exchange, and lifestyle adjustments.

Hypoglycemia Caused by Exogenous Insulin Antibody Syndrome: A Large Single-Center Case Series From China

CONTEXT

Exogenous insulin antibody syndrome (EIAS) can lead to unexpected and potentially life-threatening recurrent hypoglycemia.

OBJECTIVE

We aimed to better define autoimmune hypoglycemia caused by EIAS in patients with diabetes and shed light on the improvements in the identification and intervention for this rare but possibly life-threatening condition.

METHODS

We summarized the clinical characteristics of autoimmune hypoglycemia caused by EIAS in 23 patients with diabetes. Furthermore, we performed human leukocyte antigen (HLA) genotyping of 10 patients.

RESULTS

We identified a high frequency of autoimmune comorbidities (21.7%), food or drug allergy (48%), insulin allergy (30%), lipodystrophy at the insulin injection sites (22%), and antinuclear antibodies (25%) in the patients. Alternation between hyperglycemia and hypoglycemia was observed in more than 90% of the patients. Most patients showed a high insulin autoantibody titer (>90%) and inappropriately increased insulin concentration (insulin/C-peptide molar ratio >7, >85%). We detected similar frequencies of DRB1*0405-DQB1*0401 and DRB1*0901-DQB1*0303 compared with previously reported frequencies in type 1 diabetes, and a lower frequency of DRB1*0406 compared with insulin autoimmune syndrome. The spontaneous remission rate exceeded 70%.

CONCLUSION

Predisposing factors for autoimmune hypoglycemia caused by EIAS include a strong autoimmune background. Susceptible HLA genotypes for type 1 diabetes or insulin autoimmune syndrome might not explain susceptibility to this condition. Additionally, insulin autoantibodies and the insulin/C-peptide molar ratio are reliable screening options. The prognosis for this condition is favorable. Monitoring of insulin and insulin autoantibodies may contribute to treatment effectiveness.

Insulin Autoimmune Syndrome: A Systematic Review

Insulin autoimmune syndrome (IAS) is a rare endocrine disorder characterized by recurrent episodes of severe hypoglycemia, markedly elevated serum insulin, and positive insulin autoantibodies. In recent years, various countries have reported it one after another. It can be seen that we must pay attention to this disease. The diagnosis of IAS is challenging, requiring a careful workup aimed at excluding other causes of hyperinsulinemic hypoglycemia. High levels of insulin autoantibodies are found in patients, and C-peptide is not parallel to insulin, which could be diagnostic. IAS is a self-limiting disease with a good prognosis. Its treatment mainly includes symptomatic supportive treatment, such as adjusting the diet and using acarbose and other drugs to delay the absorption of glucose to prevent hypoglycemia. For patients with severe symptoms, available treatments may include drugs that reduce pancreatic insulin secretion (such as somatostatin and diazoxide), immunosuppressants (glucocorticoids, zaprin, and rituximab), and even plasma exchange to remove autoantibodies from the body. This review provides a comprehensive analysis of the epidemiology, pathogenesis, clinical manifestations, diagnosis and identification, and monitoring and treatment management of IAS.

The Application of the Insulin to C-Peptide Molar Ratio (ICPR) in Primary Screening for Insulin Antibodies in Type 2 Diabetes Mellitus Patients: A Further Quantitative Study on the Relationship Between ICPR and Insulin Antibodies

Purpose

This study aimed to further quantify the relationship between insulin antibodies (IAs) and the 2-hour insulin to C-peptide molar ratio (2h-ICPR) using a multiple linear regression model in T2DM patients.

Methods

A total of 274 T2DM patients from April 2019 to December 2022 in Xiang'an Hospital of Xiamen University were included in this study. Multiple Linear Model Fitting was conducted on the candidate independent variables (age, BMI, HbA1c, and 2h-ICPR) for the multiple linear regression. The linear relationship between insulin antibodies (IAs) and the significant independent variables was presented by making multiple linear regression equations.

Results

The total demographic characteristics of the included patients were as follows: age (51.92±13.10 years), BMI (24.94±3.99 kg/m²), HbA1c (9.70±2.39%), 2h-ICPR (0.12±0.11), and IAs (0.37±1.12COI). Linear relationships of independent variables: age (r=0.163, p=0.007), 2h-ICPR (r=0.259, p=0.001), BMI (r=0.007, p=0.907) and 2h-ICPR (r=0.092, p=0.129). Multiple linear regression: age (unstandardized β=0.014, 95% CI: 0.004-0.024, p=0.004), 2h-ICPR (unstandardized β=2.758, 95% CI: 1.555-3.962, p≤0.001). The regression equation: .

Conclusion

The quantitative relationship between 2h-ICPR and insulin antibodies was . 2h-ICPR can be a preliminary screening indicator for insulin antibody testing in patients with type 2 diabetes.

Insulin antibodies are prevalent in adults with type 1 diabetes referred for islet cell transplantation and are modified by islet transplantation and immunosuppression: an Australian experience

We have analysed insulin antibodies in 149 adults with type 1 diabetes and 2859 people without diabetes. We have determined that insulin antibody levels are higher in adults with, versus without, diabetes and that the levels are falling, and more patients are becoming antibody-negative post islet cell transplantation.

Hyperinsulinemia Associated Depression

Hyperinsulinemia promotes fat accumulation, causing obesity. Being an inflammatory state, obesity can induce further inflammation and is a risk factor for HPA (hypothalamic pituitary axis) dysregulation through hypercortisolism-related hyperglycemia. In another hypothesis, the sympathetic nervous system (SNS) plays a significant role in the regulation of hormone secretion from the pancreas such as an increase in catecholamines and glucagon as well as a decrease in plasma insulin levels, a disruption on SNS activity increases insulin levels, and induces glycogenolysis in the liver and lipolysis in adipose tissue during hypoglycemia. Hyperglycemia-hyperinsulinemia exacerbates inflammation and increases the oxidative stress along with regulating the levels of norepinephrine in the brain sympathetic system. Increased inflammatory cytokines have also been shown to disrupt neurotransmitter metabolism and synaptic plasticity which play a role in the development of depression via inhibiting serotonin, dopamine, melatonin, and glutamate signaling. An increased level of plasma insulin over time in the absence of exercising causes accumulation of lipid droplets in hepatocytes and striated muscles thus preventing the movement of glucose transporters shown to result in an increase in insulin resistance due to obesity and further culminates into depression. Further hyperinsulinemia-hyperglycemia condition arising due to exogenous insulin supplementation for diabetes management may also lead to physiological hyperinsulinemia associated depression. Triple therapy with SSRI, bupropion, and cognitive behavioral therapy aids in improving glycemic control, lowering fasting blood glucose, decreasing the chances of relapse, as well as decreasing cortisol levels to improve cognition and the underlying depression. Restoring the gut microbiota has also been shown to restore insulin sensitivity and reduce anxiety and depression symptoms in patients.

Characteristics of OGTT and Correlation Between the Insulin to C-Peptide Molar Ratio, HOMA-IR, and Insulin Antibodies in T2DM Patients

PURPOSE

The purpose of our study was to analyze the characteristics of OGTT and the correlation between the insulin to C-peptide molar ratio (ICPR), HOMA-IR and insulin antibodies (IAs) in T2DM patients.

PATIENTS AND METHODS

A total of 77 T2DM patients were included and divided into the IA+ group (25 patients) and IA- group (52 patients). The values of serum glucose, insulin, and C-peptide testing during 2-h OGTT were summarized comparatively, and ROC was made to analyze the predictive value of ICPR for IAs.

RESULTS

At each time point of OGTT, there was no significant difference in serum glucose and C-peptide changes (p>0.05). Serum insulin levels in positive patients were elevated or not at different time points of the OGTT but ICPR was significantly different (P<0.05) in the two groups. Spearman correlation coefficient analysis showed that the presence of insulin antibodies was correlated with ICPR, but not with HOMA-IR, and ICPR-2h had a better prediction capacity (AUC=0.735, the optimal cutoff-point=0.11, Se=0.760, Sp=0.635).

CONCLUSION

T2DM patients with IAs showed no difference in serum glucose and serum C-peptide changes, but elevated or not insulin levels on the OGTTs, compared with negative patients. ICPR-2h can be a preliminary diagnostic index to timely predict IAs in T2DM patients.

Type 1 diabetes complicated with cyclic vomiting syndrome and exogenous insulin antibody syndrome: A case report

Every fifth individual with type 1 diabetes (T1D) suffers from an additional autoimmune disorder due to shared genetic factors and dysregulated immunity. Here we report an extremely rare case of T1D complicated with cyclic vomiting and hypoglycaemia. A 27-year-old Chinese woman with 14-year history of T1D was periodically hospitalized for severe vomiting of more than 30 times a day without apparent organic causes. The vomiting developed acutely and remitted spontaneously after 2-3 days, followed with intractable hypoglycaemia for another 3-4 days during the hospitalization. A few weeks after discharge, she was admitted once again with the same symptoms and disease course. Cyclic vomiting syndrome (CVS) was diagnosed according to the Rome IV criteria, a system developed to define the functional gastrointestinal disorders. Dynamic association and disassociation of exogenous insulin and insulin antibodies (IAs) were identified in her blood during hypoglycaemia, leading to the diagnosis of exogenous insulin antibody syndrome (EIAS). Treatment with rituximab to suppress the IAs was associated with a striking amelioration of hypoglycaemia. Unexpectedly, the episodes of cyclic vomiting were also dramatically reduced. In conclusion, we identified the first case with alternating CVS and EIAS in the setting of T1D. Dynamic measurements of free and total insulin are helpful for the diagnosis of EIAS. CVS is likely to be a latent autoimmune disorder considering the good response to rituximab treatment.

Clinical and Laboratory Aspects of Insulin Autoantibody-Mediated Glycaemic Dysregulation and Hyperinsulinaemic Hypoglycaemia: Insulin Autoimmune Syndrome and Exogenous Insulin Antibody Syndrome

Autoimmune glycaemic dysregulation and hyperinsulinaemic hypoglycaemia mediated by insulin autoantibodies is an increasingly recognised but controversial phenomenon described in both exogenous insulin naïve (insulin autoimmune syndrome) and exposed (exogenous insulin antibody syndrome) individuals. There has been a significant proliferation of case reports, clinical studies and reviews in the medical literature in recent years which have collectively highlighted the discrepancy between experts in the field with regard to the nomenclature, definition, proposed pathophysiology, as well as the clinical and biochemical diagnostic criteria associated with the condition. The essential characteristics of the condition are glycaemic dysregulation manifesting as episodes of hyperglycaemia and unpredictable hyperinsulinaemic hypoglycaemia associated with high titres of endogenous antibodies to insulin. Although the hypoglycaemia is often life-threatening and initiation of targeted therapies critical, the diagnosis is often delayed and attributable to various factors including: the fact that existence of the condition is not universally accepted; the need to exclude surreptitious causes of hypoglycaemia; the diverse and often complex nature of the glycaemic dysregulation; and the challenge of diagnostic confirmation. Once confirmed, the available therapeutic options are expansive and the reported responses to these therapies have been variable. This review will focus on our evolving understanding, and the associated diagnostic challenges - both clinical and laboratory - of this complex condition.