Insulinoma Misdiagnosed as Post-bariatric Hypoglycemia: A Case Report and Review of the Literature

Hypoglycemia is seen with increasing frequency after bariatric surgery. After the diagnosis of hypoglycemia has been clarified, malnutrition, drugs, hormone deficiencies, insulinoma, extra-islet tumors, post-bariatric hypoglycemia (PBH), early or late dumping syndrome, and nesidioblastosis should be considered in the differential diagnosis. A few case reports of insulinomas presenting after bariatric surgery have been reported in the literature. The coexistence of insulinoma and type 2 diabetes mellitus (T2D) is very rare. We herein report a clinical case of insulinoma presenting with severe hypoglycemia in a patient with a history of gastric transit bipartition. A patient with type 2 diabetes mellitus underwent gastric transit bipartition surgery due to the inability of medical therapy to provide adequate hyperglycemia control. After the operation, hypoglycemic symptoms appeared, and a reversal operation was performed, considering the diagnosis as PBH. After the reverse operation, the patient's hypoglycemia symptoms did not regress. The patient was admitted to our endocrinology clinic due to the persistence of hypoglycemia and symptoms such as fatigue, palpitation, and syncope. The patient's detailed anamnesis was examined, additional tests were performed, and the patient was diagnosed with insulinoma. The symptoms of hypoglycemia and the need for treatment for diabetes mellitus disappeared after the Whipple operation. This is the first case of insulinoma after gastric transit bipartition and subsequent reversal operations. In addition, the patient's diagnosis of diabetes mellitus makes this case unique. Although this is a very rare case, clinicians must be aware of it, especially if the patient has hypoglycemic symptoms during the fasting state.

The effects of glucagon like peptide-1 (GLP-1) on cardiac remodeling: exploring the role of medication and physiological modulation after metabolic surgery

Obesity and associated comorbidities reach epidemic proportions nowadays. Several treatment strategies exist, but bariatric surgery has the only longstanding effects. Since a few years, there is increasing interest in the effects of gastro-intestinal hormones, in particular Glucagon-Like Peptide-1 (GLP-1) on the remission of Type 2 Diabetes (T2DM) and its effects on cardiac cardiovascular morbidity, cardiac remodeling, and mortality. In the past years several high quality multicenter randomized controlled trials were developed to assess the effects of GLP-1 receptor agonist therapy on cardiovascular morbidity and mortality. Most of the trials were designed and powered as non-inferiority trials to demonstrate cardiovascular safety. Most of these trials show a reduction in cardiovascular morbidity in patients with T2DM. Some follow-up studies indicate potential beneficial effects of GLP-1 receptor agonists on cardiovascular function in patients with heart failure, however the results are contradictory, and we need long-term studies to make firm conclusions about the pleiotropic properties of incretin-based therapies. However, it seems that GLP-1 receptor agonists have different effects than the increased GLP-1 production after bariatric surgery on cardiovascular remodeling. One of the hypotheses is that the blood concentrations of GLP-1 receptor agonists are three times higher compared to GLP-1 increase after bariatric and metabolic surgery. The purpose of this narrative review is to summarize the effects of GLP-1 on cardiovascular morbidity, mortality and remodeling due to medication but also due to bariatric and metabolic surgery. The second objective is to explain the possible differences in effects of GLP-1 agonists and bariatric and metabolic surgery.

The Prophylactic Effects of Metoprolol, Diltiazem, and Pilocarpine on Hypoglycemia-Induced Prolongation of QT Interval

Background Insulin-induced hypoglycemia has been demonstrated to prolong the corrected QT (QTc) interval. Prolongation of the QTc interval, especially in diabetic patients using insulin, can cause fatal ventricular arrhythmias. The aim of this study was to evaluate the effects of metoprolol, diltiazem, and pilocarpine on hypoglycemia-induced QTc prolongation. Methods Thirty male rats were randomly distributed into the following five groups: Group 1 (1 mL/kg saline, n=6), Group 2 (40 U/kg crystalline insulin + saline, n=6), Group 3 (40 U/kg crystalline insulin + 1 mg/kg metoprolol, n=6), Group 4 (40 U/kg crystalline insulin + 0.8 mg/kg pilocarpine, n=6), and Group 5 (40 U/kg crystalline insulin + 2 mg/kg diltiazem, n=6). Three hours after insulin injection, the blood glucose level was measured in all groups. Blood glucose <40 mg/dl was defined as hypoglycemia. Electrocardiograms (ECG) were taken in lead I (DI), and QTc was calculated by using Bazett's formula. Results Group 2 (insulin + saline) showed that it had a significantly prolonged QTc interval as compared to the control group (p<0.0001). However, treatments of the rats with metoprolol, pilocarpine, and diltiazem significantly prevented prolongation of the QTc interval as compared to the insulin + saline group (p<0.005, p<0.005, and p<0.01, respectively). Conclusion The findings of the present study demonstrated the efficacy of metoprolol, pilocarpine, and diltiazem in the prevention of hypoglycemia-induced QTc prolongation in male rats.

Effects of Bariatric Surgery on Heart Rhythm Disorders: a Systematic Review and Meta-Analysis

The aim of this systematic review is to provide an overview of the literature on the effects of bariatric surgery on obesity-associated electrocardiogram (ECG) abnormalities and cardiac arrhythmias. Fourteen studies were included with a methodological quality ranging from poor to good. Majority of the studies showed a significant decrease of QT interval and related measures after bariatric surgery. Seven studies were included in the meta-analysis on effects of bariatric surgery on QTc interval and a significant decrease in QTc interval of - 33.6 ms, 95%CI [- 49.8 to - 17.4] was seen. Bariatric surgery results in significant decrease in QTc interval and P-wave dispersion, i.e., a normalization of initial pathology. The effects on atrial fibrillation are conflicting and not yet fully understood.

Effects of different metabolic states and surgical models on glucose metabolism and secretion of ileal L-cell peptides: results from the HIPER-1 study

AIM

To compare the impact of four surgical procedures (mini-gastric bypass, sleeve gastrectomy, ileal transposition and transit bipartition) vs medical management on gut peptide secretion, β-cell function and resolution of hyperglycaemia in people with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A mixed-meal tolerance test was administered 6-24 months after each surgical procedure (mini-gastric bypass, sleeve gastrectomy, ileal transposition and transit bipartition; n=30 in each group) and the results were compared with those obtained in matched lean (n=30) and obese (n=30) people with type 2 diabetes undergoing medical management.

RESULTS

Participants in the mini-gastric bypass and ileal transposition groups had a greater increase in plasma glucose concentration after the mixed-meal tolerance test than those in the sleeve gastrectomy and transit bipartition groups. Participants in the mini-gastric bypass group exhibited the greatest increase in the incremental area under the curve of plasma glucose concentration above baseline (P<0.0001). Insulin sensitivity was similar across surgical groups, and statistically greater in participants in the surgical groups than in obese participants in the non-surgical group (P<0.0001). β-cell responsiveness to glucose was greater in participants in the sleeve gastrectomy and transit bipartition groups than in the mini-gastric bypass and ileal transposition groups (P<0.001) despite a smaller incremental increase above baseline in the area under the plasma glucagon-like peptide-1 concentration curve relative to ileal transposition. Postoperative β-cell function was the strongest predictor of hyperglycaemia resolution.

CONCLUSIONS

The present study showed that the level of β-cell function after bariatric surgery is the strongest predictor of hyperglycaemia resolution. The study also demonstrates a disconnect between postprandial GLP-1 levels and β-cell function among the studied surgical procedures.

Perioperative Exercise Therapy in Bariatric Surgery: Improving Patient Outcomes

Nowadays, obesity and related comorbidities like type 2 diabetes, hypertension, dyslipidaemia and obstructive sleep apnoea syndrome are considered one of the medical challenges of the 21st century. Even with the rise of bariatric and metabolic surgery, obesity and metabolic syndrome are reaching endemic proportions. Even in 2020, obesity is still a growing problem. There is increasing evidence that next to bariatric surgery, exercise interventions in the perioperative period could give extra beneficial effects. In this regard, effects on anthropometrics, cardiovascular risk factors and physical fitness. The aim of this review is to summarise effects of preoperative and postoperative exercise, tools for screening and directions for future research and implementations.

Identification of a Novel Deletion in AVP-NPII Gene in a Patient with Central Diabetes Insipidus

Central Diabetes Insipidus (CDI) is caused by a deficiency of antidiuretic hormone and characterized by polyuria, polydipsia and inability to concentrate urine. Our objective was to present the results of the molecular analyses of AVP-neurophysin II (AVP-NPII) gene in a large familial neurohypophyseal (central) DI pedigree. A male patient and his family members were analyzed and the prospective clinical data were collected. The proband applied to hospital for eligibility to be a recruit in Armed Forces. The patient had severe polyuria (20 L/day), polydipsia (20.5 L/day), fatique, and deep thirstiness. CDI was confirmed with the water deprivation-desmopressin test according to an increase in urine osmolality from 162 mOsm/kg to 432 mOsm/kg after desmopressin acetate injection. To evaluate the coding regions of AVP-NPII gene, polymerase chain reactions were performed and amplified regions were submitted to direct sequence analysis. We detected a heterozygous three base pair deletion at codon 69-70 (207_209delGGC) in exon 2, which lead to a deletion of the amino acid alanine. A three-dimensional protein structure prediction was shown for the deleted AVP-NPII and compared with the wild type. The three base pair deletion may yield an abnormal AVP precursor in neurophysin moiety, but further functional analyses are needed to understand the function of the deleted protein.

A large deletion of the AVPR2 gene causing severe nephrogenic diabetes insipidus in a Turkish family

X-linked nephrogenic diabetes insipidus (NDI) is a rare hereditary disease caused by mutations in arginine vasopressin type 2 receptor (AVPR2) and characterized by the production of large amounts of urine and an inability to concentrate urine in response to the antidiuretic hormone vasopressin. We have identified a novel 388 bp deletion starting in intron 1 and ending in exon 2 in the AVPR2 gene in a patient with NDI and in his family. We have revealed that this mutation is a de novo mutation for the mother of the proband patient. Prospective clinical data were collected for all family members. The water deprivation test confirmed the diagnosis of diabetes insipidus. The patient has severe symptoms like deep polyuria nocturia, polydipsia, and fatigue. He was given arginine vasopressin treatment while he was a child. However, he could not get well due to his nephrogenic type of illness. Both of his nephews have the same complains in addition to failure to grow. We have sequenced all exons and intron-exon boundaries of the AVPR2 gene of all family members. The analyses of bioinformatics and comparative genomics of the deletion were done via considering the DNA level damage. AVPR2 gene mutation results in the absence of the three transmembrane domains, two extracellular domains, and one cytoplasmic domain. Three-dimensional protein structure prediction was shown. We concluded that X-linked NDI and severity of illness in this family is caused by a novel 388 bp deletion in the AVPR2 gene that is predicted to truncate the receptor protein, and also this deletion may lead to dysfunctioning in protein activity and inefficient or inadequate binding abilities.

Plasma osteoprotegerin concentrations in type 2 diabetic patients and its association with neuropathy

BACKGROUND AND AIMS

To investigate the association of plasma osteoprotegerin (OPG) levels with diabetic neuropathy.

METHODS

Forty-two diabetic patients (21 female and 21 male) and twenty-four non-diabetic healthy control subjects (12 female and 12 male) were included in the study. All consecutive diabetic patients who came for routine follow-up at our outpatient clinic were invited to participate in this clinical study. We studied EMG and neuropathy symptom score in all study subjects. Fasting plasma glucose, HbA1 C, hs-CRP, OPG levels and lipid profile were measured for each subject.

RESULTS

Serum fasting glucose, HbA1c, HOMA-IR, total cholesterol, triglyserid, LDL-Cholesterol, HDL-Cholesterol, lipoprotein (a), apolipoprotein-b, hs-CRP, OPG levels, and neuropathy symptom score were statistically higher in diabetic patients than in healthy control subjects. Plasma OPG levels was statistically higher in diabetic patients than it was in nondiabetic control subjects. However, plasma OPG levels were not significantly different between diabetic patients without neuropathy and healthy control subjects. On the other hand, OPG levels were statistically higher in diabetic patients with neuropathy than in patients without neuropathy. In addition to that serum fasting glucose, HbA1c, hs-CRP, diabetes duration, neuropathy symptom score were statistically higher in diabetic patients with neuropathy than they were in patients without neuropathy. In total group of subjects, plasma OPG levels were correlated significantly with age, diabetes duration, HbA1c, total cholesterol, HDL-cholesterol, lipoprotein (a), apolipoprotein b, hs-CRP. In diabetic patients, plasma OPG correlated significantly with age, diabetes duration, neuropathy symptom score, HbA1c, lipoprotein (a), apolipoprotein b levels.

CONCLUSIONS

The major findings of this study were that the plasma OPG concentrations were higher in type 2 diabetic patients than OPG concentrations in healthy control subjects and they were positively correlated with diabetic neuropathy. This finding supports the growing concept that OPG acts as an important regulator in the development of vascular dysfunction in diabetes.