Hypoglycemia complicating bariatric surgery: incidence and mechanisms

Adverse Health Outcomes Associated with Hypoglycemia Following Bariatric Surgery

Introduction: Hypoglycemia is prevalent among patients postbariatric surgery, but its clinical implications remain unclear. The purpose of this study was to examine the longitudinal associations of hypoglycemia (i.e., occurrence in the past 3 months, frequency in the past 7 days, number of severe episodes in the past 3 months, and symptoms) with depressive symptoms, quality of life (QoL), work productivity, and weight loss over an 84-month follow-up period after bariatric surgery. Methods: This secondary analysis used data from the Longitudinal Assessment of Bariatric Surgery-2 study. Hypoglycemia, depressive symptoms, QoL, and work productivity were self-reported. Weight was primarily based on objective measures. Linear mixed modeling with time-lagged techniques was used for analysis, adjusting for potential covariates such as age and gender. Results: Across the 84-month follow-up, 20%-30% of participants (N = 552) reported experiencing hypoglycemia in the past 3 months. Hypoglycemia occurrence was positively associated with depressive symptoms [β = 2.4; 95% confidence interval (CI): 1.7, 3.0] and negatively associated with physical (β = -4.2; 95% CI: -5.1, -3.3) and mental QoL (β = -3.4; 95% CI: -4.4, -2.4). These associations became stronger with increased frequency of hypoglycemia, a higher number of severe episodes, and the presence of symptoms. Additionally, hypoglycemia occurrence was associated with several domains of work productivity, including presenteeism (β = 5.8; 95% CI: 3.4, 8.2), work productivity loss (β = 5.6; 95% CI: 2.6, 8.6), and activity impairment (β = 8.8; 95% CI: 6.0, 11.6), with the strength of these associations increasing with greater hypoglycemic frequency. Conclusions: This study highlights the critical role of hypoglycemia in patients' physical and psychosocial well-being postbariatric surgery. Future studies employing more rigorous measures of hypoglycemia and expanded outcomes (e.g. cognitive function) are needed to fully understand its clinical relevance.

Ketotic Hypoglycaemia Following Sleeve Gastrectomy

Post-bariatric surgery hypoglycaemia is typically mediated by hyperinsulinaemia, although the exact mechanisms are incompletely understood. Two cases of non-insulin mediated, ketotic hypoglycaemia following sleeve gastrectomy are presented. After fasting for 40 and 65 h, respectively, both patients developed symptomatic hypoglycaemia, with corresponding low insulin, low c-peptide and elevated beta-hydroxybutyrate levels. Morning cortisol and IGF1 levels were normal. Potential mechanisms for ketotic hypoglycaemia following bariatric surgery include reduction in hepatic, renal and intestinal gluconeogenesis, or alternatively an underlying inborn error of metabolism such as a glycogen storage disorder unmasked by bariatric surgery. Most glycogen storage disorders present in childhood, but there have been rare case reports of glycogen storage disorders types I, III and IX diagnosed in adulthood. Neither of the above cases had other features of a glycogen storage disorder such as elevated lactate, hyperuricaemia, hypertriglyceridaemia, hepatomegaly, myopathy or an indicative family history. Both patients trialled first-line dietary management, which was inadequate in managing hypoglycaemia. Treatment with the glucagon-like peptide-1 receptor agonist semaglutide resulted in the resolution of hypoglycaemic episodes in one patient, and a significant reduction in hypoglycaemic episodes in the other patient.

The relation between postprandial glucagon-like peptide-1 release and insulin sensitivity before and after bariatric surgery in humans with class II/III obesity

BACKGROUND

Glucagon-like peptide-1 (GLP-1) receptor agonist treatment is beneficial for the human glucose metabolism, and GLP-1 secretion is greatly enhanced following Roux-en-Y gastric bypass (RYGB).

OBJECTIVES

To elucidate the relationship between GLP-1 concentrations and insulin sensitivity in subjects with class II/III obesity without diabetes and to assess the relation between GLP-1 and the improvements in glucose metabolism following RYGB.

SETTING

Clinical research facility in a university hospital.

METHODS

We recruited 35 patients scheduled for RYGB and assessed their plasma GLP-1, insulin, and glucose responses to a high-fat mixed meal. Basal and insulin-mediated glucose fluxes were determined during a 2-step hyperinsulinemic-euglycemic clamp with stable isotope-labeled tracers. Out of 35 subjects, 10 were studied both before surgery and at 1 year of follow-up.

RESULTS

Plasma GLP-1 increased following the high-fat mixed meal. Postprandial GLP-1 excursions correlated positively with hepatic and peripheral insulin sensitivity, but not with body mass index. At 1 year after RYGB, participants had lost 24% ± 6% of their body weight. Plasma GLP-1, insulin, and glucose levels peaked earlier and higher after the mixed meal. The positive association between the postprandial GLP-1 response and peripheral insulin sensitivity persisted.

CONCLUSIONS

Postprandial GLP-1 concentrations correlate with insulin sensitivity in subjects with class II/III obesity without diabetes before and 1 year after RYGB. Increased GLP-1 signaling in postbariatric patients may, directly or indirectly, contribute to the observed improvements in insulin sensitivity and metabolic health.

Hyperinsulinemic hypoglycemia in children and adolescents: Recent advances in understanding of pathophysiology and management

Hyperinsulinemic hypoglycemia (HH) is characterized by unregulated insulin release, leading to persistently low blood glucose concentrations with lack of alternative fuels, which increases the risk of neurological damage in these patients. It is the most common cause of persistent and recurrent hypoglycemia in the neonatal period. HH may be primary, Congenital HH (CHH), when it is associated with variants in a number of genes implicated in pancreatic development and function. Alterations in fifteen genes have been recognized to date, being some of the most recently identified mutations in genes HK1, PGM1, PMM2, CACNA1D, FOXA2 and EIF2S3. Alternatively, HH can be secondary when associated with syndromes, intra-uterine growth restriction, maternal diabetes, birth asphyxia, following gastrointestinal surgery, amongst other causes. CHH can be histologically characterized into three groups: diffuse, focal or atypical. Diffuse and focal forms can be determined by scanning using fluorine-18 dihydroxyphenylalanine-positron emission tomography. Newer and improved isotopes are currently in development to provide increased diagnostic accuracy in identifying lesions and performing successful surgical resection with the ultimate aim of curing the condition. Rapid diagnostics and innovative methods of management, including a wider range of treatment options, have resulted in a reduction in co-morbidities associated with HH with improved quality of life and long-term outcomes. Potential future developments in the management of this condition as well as pathways to transition of the care of these highly vulnerable children into adulthood will also be discussed.

Concurrent Adult-Onset Diffuse β-Cell Nesidioblastosis and Pancreatic Neuroendocrine Tumor: A Case Report and Review of the Literature

Nesidioblastosis is an uncommon cause of organic persistent hyperinsulinemic hypoglycemia in adults. We report a case of adult-onset diffuse β-cell nesidioblastosis in a 49-year-old woman who was status-post Roux-en-Y gastric bypass and distal pancreatectomy for a well-differentiated pancreatic neuroendocrine tumor. While the neuroendocrine tumor was suspected to be an insulinoma, persistent hypoglycemia postoperatively suggested either incomplete resection or a second pancreatic neoplasm. Completion pancreatectomy revealed islet β-cell hyperplasia and nuclear pleomorphism consistent with β-cell nesidioblastosis. The patient's blood glucose levels normalized after completion pancreatectomy. While β-cell nesidioblastosis and insulinomas can coexist in the same patient, pathologists should be aware of β-cell nesidioblastosis as a potential cause for hyperinsulinemic hypoglycemia and should exclude it in patients who have not shown definitive clinical response after surgical excision of a pancreatic neuroendocrine tumor.

Effect of alcohol ingestion on plasma glucose kinetics after Roux-en-Y gastric bypass surgery

BACKGROUND

Roux-en-Y gastric bypass surgery (RYGB) increases the rate of alcohol absorption so that peak blood alcohol concentration is 2-fold higher after surgery compared with concentrations reached after consuming the same amount presurgery. Because high doses of alcohol can lead to hypoglycemia, patients may be at increased risk of developing hypoglycemia after alcohol ingestion.

OBJECTIVES

We conducted 2 studies to test the hypothesis that the consumption of approximately 2 standard drinks of alcohol would decrease glycemia more after RYGB than before surgery.

SETTING

Single-center prospective randomized trial.

METHODS

We evaluated plasma glucose concentrations and glucose kinetics (assessed by infusing a stable isotopically labelled glucose tracer) after ingestion of a nonalcoholic drink (placebo) or an alcoholic drink in the following groups: (1) 5 women before RYGB (body mass index = 43 ± 5 kg/m²) and 10 ± 2 months after RYGB (body mass index = 31 ± 7 kg/m²; study 1), and (2) 8 women who had undergone RYGB surgery 2.2 ± 1.2 years earlier (body mass index = 30 ± 5 kg/m²; study 2) RESULTS: Compared with the placebo drink, alcohol ingestion decreased plasma glucose both before and after surgery, but the reduction was greater before (glucose nadir placebo = -.4 ± 1.0 mg/dL versus alcohol = -9.6 ± 1.5 mg/dL) than after (glucose nadir placebo = -1.0 ± 1.6 mg/dL versus alcohol = -5.5 ± 2.6 mg/dL; P < .001) surgery. This difference was primarily due to an alcohol-induced early increase followed by a subsequent decrease in the rate of glucose appearance into systemic circulation.

CONCLUSION

RYGB does not increase the risk of hypoglycemia after consumption of a moderate dose of alcohol.

Incidence and Predictors of Hypoglycemia 1 Year After Laparoscopic Sleeve Gastrectomy

INTRODUCTION

Hypoglycemia is a known adverse event following gastric bypass. The incidence of hypoglycemia after laparoscopic sleeve gastrectomy (LSG) is still under investigation. The aim of our study was to verify the presence of oral glucose tolerance test (OGTT)-related hypoglycemia after LSG and to identify any baseline predictors of its occurrence.

METHODS

We analyzed 197 consecutive non-diabetic morbid obese patients that underwent LSG. All patients were studied before and 12 months after LSG. Evaluation included anthropometric parameters, 3-h OGTT for blood glucose (BG), insulin and c-peptide, lipid profile, interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), highly sensitive C-reactive protein (hsCRP), and leptin. Hypoglycemia was defined as BG ≤ 2.7 mmol/l.

RESULTS

After surgery, 180 patients completed the OGTT. Eleven patients did not complete the test for gastric intolerance, and in six patients, the test was stopped earlier for the onset of severe symptomatic hypoglycemia. Of the patients, 61/186 (32.8%) had at least one OGTT-related hypoglycemia. The highest frequency of hypoglycemic events occurred 150' after glucose load (20.2%). At baseline, patients with hypoglycemic events after surgery (Hypo) were younger (40 ± 11 vs 46 ± 10 years; p < 0.001), less obese (BMI 46 ± 5.7 vs 48.4 ± 7.9 kg/m²; p < 0.05), and had a worse lipid profile as compared to patients without hypoglycemic events (N-Hypo). Moreover, after LSG, Hypo patients compared with N-Hypo presented a higher weight loss (%EBMIL 80 ± 20 vs 62 ± 21%; p < 0.001). Low age, low fasting glucose, and high triglyceride levels before LSG were independent predictors of hypoglycemia development after surgery (r ² = 0.131).

CONCLUSION

These findings confirm the high incidence of post-prandial hypoglycemia 1 year after LSG. Hypoglycemia is more frequent in younger patients with lower fasting glucose and higher triglyceride levels before surgery.

Is testing for postprandial hyperinsulinemic hypoglycemia after gastric bypass necessary?

INTRODUCTION

Postprandial hyperinsulinemic hypoglycemia (pHH) is an increasingly reported complication after Roux-en-Y gastric bypass (RYGB). As pHH can cause life-threatening emergencies if occurring without warning symptoms, challenge testing may detect patients at risk. The study objective was to determine the frequency of occurrence of pHH with or without symptoms of hypoglycemia after RYGB.

METHODS

We undertook an observational cohort study of consecutive, unselected patients approximately one year after uncomplicated RYGB. To simulate normal habits, all patients received a standardized carbohydrate-rich solid mixed meal. Plasma glucose and insulin were measured at 30, 60, 90, 120, and 150 min thereafter. Symptoms were classified as autonomous or neuroglycopenic. Patients with hypoglycemia (plasma glucose <3.0 mmol/L [55 mg/dL]), were tested a second time with a protein-rich solid mixed meal.

RESULTS

113 patients were included. Total weight loss at the first follow-up check (14 ± 0.4 months) was 33.97 ± 9.3%. After the carbohydrate-rich meal, glucose dropped to <3.0 mmol/L in 13.2% (n = 15) of patients vs no drop to <3.0 mmol/L after a protein-rich meal. The pHH occurred in 11.5% (n = 13) of patients. Asymptomatic patients (5.3%, n = 6) carried an increased risk (p = 0.008) for pHH. One patient needed emergency treatment after sudden loss of consciousness after the carbohydrate-rich meal.

CONCLUSIONS

The occurrence of pHH was quite high in our study population with 11.5% thereof 5.3% asymptomatic. We therefore suggest that detection of these patients warrants a screening of patients after RYGB. At-risk patients should than be adequately advised to avoid carbohydrate-rich meals in order to optimize risk management.

Hyperinsulinaemic hypoglycaemia in children and adults

Pancreatic β cells are functionally programmed to release insulin in response to changes in plasma glucose concentration. Insulin secretion is precisely regulated so that, under normal physiological conditions, fasting plasma glucose concentrations are kept within a narrow range of 3·5-5·5 mmol/L. In hyperinsulinaemic hypoglycaemia, insulin secretion becomes dysregulated (ie, uncoupled from glucose metabolism) so that insulin secretion persists in the presence of low plasma glucose concentrations. Hyperinsulinaemic hypoglycaemia is the most common cause of severe and persistent hypoglycaemia in neonates and children. At a molecular level, mutations in nine different genes can lead to the dysregulation of insulin secretion and cause this disorder. In adults, hyperinsulinaemic hypoglycaemia accounts for 0·5-5·0% of cases of hypoglycaemia and can be due either to β-cell tumours (insulinomas) or β-cell hyperplasia. Rapid diagnosis and prompt management of hyperinsulinaemic hypoglycaemia is essential to avoid hypoglycaemic brain injury, especially in the vulnerable neonatal and childhood periods. Advances in the field of hyperinsulinaemic hypoglycaemia include use of rapid molecular genetic testing for the disease, application of novel imaging techniques (6-[fluoride-18]fluoro-levodopa [¹⁸F-DOPA] PET-CT and glucagon-like peptide 1 (GLP-1) receptor imaging), and development of novel medical treatments (eg, long-acting octreotide formulations, mTOR inhibitors, and GLP-1 receptor antagonists) and surgical therapies (eg, laparoscopic surgery).

Postprandial hyperinsulinemic hypoglycemia in a child as a late complication of esophageal reconstruction

BACKGROUND

Postprandial hyperinsulinemic hypoglycemia (PHH) is an increasingly recognized complication of gastric bypass surgery in obese adults, distinct from the "dumping syndrome".

CASE PRESENTATION

Upon birth, primary repair of esophageal atresia was performed, and at the age of 14 months definite esophageal reconstruction was performed. At the age of 3 years, recurrent brief episodes of symptomatic hypoglycemia started. At the age of 5.7 years the girl was admitted to our clinic and investigations indicated hyperinsulinemic hypoglycemia. Oral glucose tolerance test (OGTT) and continuous glucose monitoring results revealed frequent postprandial hypoglycemic events, which were always preceded by early postprandial hyperglycemia. It was concluded that the patient had PHH caused by a delayed and hyperinsulinemic response to carbohydrate intake as a result of esophagogastric surgery. Treatment with acarbose was titrated using flash glucose monitoring, which resulted in satisfactory glucose regulation.

CONCLUSIONS

This is the first described case of a child with PHH following esophageal reconstruction.

The short- to mid-term symptom prevalence of dumping syndrome after primary gastric-bypass surgery and its impact on health-related quality of life

BACKGROUND

Early and late dumping are complications of gastric bypass surgery. Early dumping occurs within an hour after eating, when the emptying of food into the small intestine triggers rapid fluid shifts into the intestinal lumen and the release of gastrointestinal hormones, resulting in gastrointestinal and vasomotor symptoms. Late dumping occurs between 1 and 3 hours after carbohydrate ingestion and is caused by an exaggerated insulin release, resulting in hypoglycemia. Almost no data are currently available on the prevalence of early and late dumping or their impact on health-related quality of life (QoL).

OBJECTIVES

To study the prevalence of early and late dumping in a large population of patients having undergone a primary Roux-en-Y gastric bypass (RYGB) and its effect on QoL.

SETTING

Cross-sectional study at a single bariatric department in the Medical Center Leeuwarden, The Netherlands between 2008 and 2011.

METHODS

In 2013, this descriptive cohort study approached by email or post all patients who underwent a primary RYGB in the setting between 2008 and 2011 in one hospital. These patients were asked to fill in standardized questionnaires measuring their QoL (RAND-36), anxiety and depression (HADS), fatigue (MFI-20) and any disease specific indicators of early and late dumping syndrome.

RESULTS

The questionnaire was completed and returned by 351 of 613 patients (57.1%) and 121 nonobese volunteers. Participants were mostly female (80%), aged 42 (40-54 years), with an excess weight loss of 76.8% [IQR 61-95] after RYGB surgery 2.3 [ IQR 1.6-3.4] years earlier. Self-reported complaints of moderate to severe intensity suggestive of early and late dumping were present in 18.8% and 11.7% of patients, respectively. Patients with early and late dumping demonstrated significantly lower scores on the RAND-36 and HADS compared with patients without dumping. No differences were seen in the MFI-20 scores between patients with or without early and late dumping.

CONCLUSION

In this descriptive cohort, self-reported complaints suggestive of early and late dumping of moderate-to-severe intensity were, respectively, 18.8% and 11.7% in a cohort after primary gastric bypass surgery. These complaints were associated with markedly reduced health-related QoL.

Robotic pancreas transplantation in a type 1 diabetic patient with morbid obesity: A case report

RATIONALE

Obesity is considered a relative contraindication to pancreas transplantation due to increased risks of wound-related complications. Robotic surgeries have never been applied for pancreas transplantation in obese recipients though robotic kidney transplantation did and already proved its value in reducing wound-related complications in obese recipients.

PATIENT CONCERNS & DIAGNOSES

We performed the first robotic pancreas after kidney transplantation for a 34-year-old Hispanic type 1 diabetic male with class III obesity (BMI = 41 kg/m).

INTERVENTIONS

The pancreas graft was procured and benched in the standard fashion. Methylene blue was used to detect any vascular leaks. The operation was completed via two 12-mm ports (camera, laparoscopic bed-side assistance), two 8-mm ports for robotic arms, and a 7-cm epigastric incision for hand port. The portal vein and arterial Y-graft of the pancreas were anastomosed to the recipient's left external iliac vein and artery, respectively. Duodenum-bladder drainage was performed with a circular stapler.

OUTCOMES

Duration of warm and cold ischemia was: 45 minutes and 7 hours, respectively. The patient was discharged uneventfully without wound-related complications. Excellent metabolic control was achieved with hemoglobin A1c lowering from 9% before transplantation to 4.4% on day 120. The patient remained in nondiabetic status in 1-year follow-up.

LESSONS

In conclusion, robotic pancreas transplantation is feasible in patients with morbid obesity.

Characterizing the dynamic interaction among gastric emptying, glucose absorption, and glycemic control in nondiabetic obese adults

The effects of altered gastric emptying on glucose absorption and kinetics are not well understood in nondiabetic obese adults. The aim of this work was to develop a physiology-based model that can characterize and compare interactions among gastric emptying, glucose absorption, and glycemic control in nondiabetic obese and lean healthy adults. Dynamic glucose, insulin, and gastric emptying (measured with breath test) data from 12 nondiabetic obese and 12 lean healthy adults were available until 180 min after an oral glucose tolerance test (OGTT) with 10, 25, and 75 g of glucose. A physiology-based model was developed to characterize glucose kinetics applying nonlinear mixed-effects modeling with NONMEM7.3. Glucose kinetics after OGTT was described by a one-compartment model with an effect compartment to describe delayed insulin effects on glucose clearance. After the interactions between individual gastric emptying and glucose absorption profiles were accounted for, the glucose absorption rate was found to be similar in nondiabetic obese and lean controls. Baseline glucose concentration was estimated to be only marginally higher in nondiabetic obese subjects (4.9 vs. 5.2 mmol/l), whereas insulin-dependent glucose clearance in nondiabetic obese subjects was found to be cut in half compared with lean controls (0.052 vs. 0.029 l/min) and the insulin concentration associated with 50% of insulin-dependent glucose elimination rate was approximately twofold higher in nondiabetic obese subjects compared with lean controls (7.1 vs. 15.3 μU/ml). Physiology-based models can characterize and compare the dynamic interaction among gastric emptying, glucose absorption and glycemic control in populations of interest such as lean healthy and nondiabetic obese adults.

[Conversional and endoscopic procedures following bariatric surgery]

The Roux-en-Y gastric bypass (RYGB) is the therapy of choice in bariatric surgery. Sleeve gastrectomy and gastric banding are showing higher rates of treatment failure, reducing obesity-associated morbidity and body weight insufficiently. Moreover, gastroesophageal reflux disease (GERD) can occur refractory to medication. Therefore, a laparoscopic conversion to RYGB can be reasonable as long as specific conditions are fulfilled.Endoscopic procedures are currently being applied to revise bariatric procedures. Therapy failure following RYGB occurs in up to 20 % of cases. Transoral outlet reduction is the minimally invasive method of choice to reduce gastrojejunal anastomosis of the alimentary limb. The diameter of a gastric sleeve can be unwantedly enlarged as well; that can be reduced by placement of a longitudinal full-thickness suture.Severe hypoglycemic episodes can be present in patients following RYGB. Hypoglycemic episodes have to be diagnosed first and can be treated conventionally. Alternatively, a laparoscopic approach according to Branco-Zorron can be used for non-responders. Hypoglycemic episodes can thus be prevented and body weight reduction can be assured.Conversional and endoscopic procedures can be used in patients with treatment failure following bariatric surgery. Note that non-invasive approaches should have been applied intensively before a revisional procedure is performed.

A novel technique of Roux-en-Y gastric bypass reversal for postprandial hyperinsulinemic hypoglycaemia: A case report

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Postprandial hypoglycemia may be a serious adverse effect following Roux-en-Y gastric bypass surgery.

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Most patient can be treated with diet and pharmacological agents, but some patients need surgical reversals.

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This Roux-en-Y gastric bypass reversal alleviates severe postprandial hyperinsulinaemic hypoglycaemia.

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The technique retains some component of rapid transit of food into a shorter alimentary limb in an attempt to reduce weight regain.

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This new surgical procedure also attenuates s-GLP-1 and s-insulin responses along with improved p-glucose.

Background

We describe an evaluation of the effects of partial Roux-en-Y gastric bypass (RYGB) reversal on postprandial hyperinsulinaemic hypoglycaemia, insulin and GLP-1 levels.

Case summary

A 37 year old man was admitted with neuroglycopenia (plasma–glucose 1.6 mmol/l) 18 months after RYGB, with normal 72 h fasting test and abdominal CT. Despite dietary modifications and medical treatment, the hypoglycaemic episodes escalated in frequency. Feeding by a gastrostomy tube positioned in the gastric remnant did not prevent severe episodes of hypoglycaemia. A modified reversal of the RYGB was performed. Mixed meal tests were done perorally (PO), through the gastrostomy tube 1 (GT1), 4 weeks (GT2) after placement and 4 weeks after reversal (POr), with assessment of glucose, insulin and GLP-1 levels.

Results

Plasma–glucose increased to a maximum of 9.6, 5.4, 6.5 and 5.8 mmol/l at the PO, GT1, GT2 and POr tests respectively. The corresponding insulin levels were 2939, 731, 725 and 463 pmol/l. A decrease of plasma–glucose followed: 2.2, 3.0, 3.9 and 2.9 mmol/l respectively and insulin levels were suppressed at 150 min: 45, 22, 21 and 14 pmol/l, respectively. GLP-1 levels increased in the PO test (60 min: 122 pmol/l, 21 fold of basal), but was attenuated in the two latter tests (12–23 pmol/l at 60 min).

Conclusions

Reduction of plasma–glucose, insulin and GLP-1 excursions and symptoms were seen after gastric tube placement and partial RYGB reversal. This attenuation of GLP-1 response to feeding could reflect an adaptation to nutrients.

Adverse effects during the oral glucose tolerance test in post-bariatric surgery patients

OBJECTIVE

The oral glucose tolerance test (OGTT) is used in the screening of gestational diabetes, in diagnosis of type 2 diabetes in conjunction with fasting blood glucose and glycated hemoglobin. The aim of this study was to examine the incidence and risk factors of adverse effects of OGTT in patients who underwent bariatric surgery, in addition to proposing standardization for ordering the OGTT in these patients.

SUBJECTS AND METHODS

This study assessed the incidence of adverse effects in 128 post-bariatric surgery patients who underwent the OGTT. Descriptive and logistic regression analysis were performed, the dependent variables were defined as the presence of signs (tremor, profuse sweating, tachycardia), symptoms (nausea, diarrhea, dizziness, weakness), and hypoglycemia (blood glucose ≤ 50 mg/dL).

RESULTS

One hundred and seventeen participants (91.4%) were female; 38 (29.7%) participants were pregnant. High incidence (64.8%) of adverse effects was observed: nausea (38.4%), dizziness (30.5%), weakness (25.8%), diarrhea (23.4%), hypoglycemia (14.8%), tachycardia (14.1%), tremor (13.3%), profuse sweating (12.5%) and one case of severe hypoglycemia (24 mg/dL). The presence of signs was associated with hypoglycemia (OR = 8.1, CI 95% 2.6-25.1). The arterial hypertension persisted as a risk factor for the incidence of signs (OR = 3.6, CI 95% 1.2-11.3). Fasting glucose below 75 mg/dL increased the risk of hypoglycemia during the test (OR = 9.5, CI 95% 2.6-35.1).

CONCLUSION

In this study, high incidence of adverse effects during the OGTT was observed in post-bariatric surgery patients. If these results are confirmed by further studies, the indication and regulation of the OGTT procedure must be reviewed for these patients.

Nutritional and Protein Deficiencies in the Short Term following Both Gastric Bypass and Gastric Banding

BACKGROUND

The number of morbidly obese patients undergoing bariatric surgery (BS) has increased dramatically in recent years. Therefore, monitoring food intake and its consequences in terms of nutritional status is necessary to prevent nutritional deficiencies. The aim of this study was to analyze the effect of food restriction on nutritional parameters in the short-term (≤3 months) period after BS in morbid obesity.

METHOD

In a prospective study, we followed 22 obese women who underwent Roux-en-Y gastric bypass (GBP) or adjustable gastric banding (AGB) at baseline (T0) and 1 (T1) and 3 (T3) months after surgery. We evaluated food intake, nutrient adequacy and serum concentrations of vitamins and minerals known to be at risk for deficiency following BS.

RESULTS

Before surgery, we observed suboptimal food intakes, leading to a risk of micronutrient deficiencies. Serum analysis confirmed nutritional deficiencies for iron and thiamine for 27 and 23% of the patients, respectively. The drastic energy and food reduction seen in the short term led to very low probabilities of adequacy for nutrients equivalent across both surgeries. Serum analysis demonstrated a continuous decrease in prealbumin during the follow-up, indicating mild protein depletion in 21 and 57% of GBP patients and 50 and 63% of AGB patients, respectively, at T1 and T3. Regarding vitamins and minerals, systematic supplementation after GBP prevented most nutritional deficiencies. By contrast, AGB patients, for whom there is no systematic supplementation, developed such deficiencies.

CONCLUSIONS

Our results suggest that cautious monitoring of protein intake after BS is mandatory. Furthermore, AGB patients might also benefit from systematic multivitamin and mineral supplementation at least in the short term.

Post-Gastric Bypass Hypoglycemia

Obesity is a major public health problem worldwide. Obesity-related illnesses, such as coronary heart disease, type 2 diabetes, hypertension, dyslipidemia, stroke, sleep apnea, and several forms of cancer (endometrial, breast, and colon), contribute to a significant number of deaths in the USA. Bariatric surgery, including the Roux-en-Y gastric bypass (RYGB) procedure, has demonstrated significant improvements in obesity and obesity-related co-morbidities and is becoming more popular as the number of obese individuals rises. Despite the reported benefits of bariatric surgery, there are potential complications that physicians need to be aware of as the number of patients undergoing these procedures continues to increase. One challenging and potentially life-threatening complication that to date is not well understood is post-RYGB surgery hypoglycemia (PGBH). In this review, we will present the definition, historical perspective, diagnostic approach, currently available treatment options, and anecdotal assessment and treatment algorithm for this disorder.

FROM COMPLEX EVOLVING TO SIMPLE: CURRENT REVISIONAL AND ENDOSCOPIC PROCEDURES FOLLOWING BARIATRIC SURGERY

Background

Roux-en-Y gastric bypass (RYGB) is a standard therapy in bariatric surgery. Sleeve gastrectomy and gastric banding, although with good results in the literature, are showing higher rates of treatment failure to reduce obesity-associated morbidity and body weight. Other problems after bariatric may occur, as band erosion, gastroesophageal reflux disease and might be refractory to medication. Therefore, a laparoscopic conversion to a RYGB can be an effective alternative, as long as specific indications for revision are fulfilled.

Objective

The objective of this study was to analyse own and literature data on revisional bariatric procedures to evaluate best alternatives to current practice.

Methods

Institutional experience and systematic review from the literature on revisional bariatric surgery.

Results

Endoscopic procedures are recently applied to ameliorate failure and complications of bariatric procedures. Therapy failure following RYGB occurs in up to 20%. Transoral outlet reduction is currently an alternative method to reduce the gastrojejunal anastomosis. The diameter and volume of sleeve gastrectomy can enlarge as well, which can be reduced by endoscopic full-thickness sutures longitudinally. Dumping syndrome and severe hypoglycemic episodes (neuroglycopenia) can be present in patients following RYGB. The hypoglycemic episodes have to be evaluated and usually can be treated conventionally. To avoid partial pancreatectomy or conversion to normal anatomy, a new laparoscopic approach with remnant gastric resection and jejunal interposition can be applied in non-responders alternatively. Hypoglycemic episodes are ameliorated while weight loss is sustained.

Conclusion

Revisional and endoscopic procedures following bariatric surgery in patients with collateral symptomatic or treatment failure can be applied. Conventional non-surgical approaches should have been applied intensively before a revisional surgery will be indicated. Former complex surgical revisional procedures are evolving to less complicated endoscopic solutions.

Effect of carbohydrate restriction in patients with hyperinsulinemic hypoglycemia after Roux-en-Y gastric bypass

BACKGROUND

Hyperinsulinemic hypoglycemia is a rare complication of Roux-en-Y gastric bypass (RYGB) surgery. Meals with a high carbohydrate (carb) content and high glycemic index (GI) may provoke these hypoglycemic attacks. The aim of this study is to assess the effects of reducing meal carb content and GI on glycemic responses in patients with post-RYGB hypoglycemia.

METHODS

Fourteen patients with post-RYGB hypoglycemia underwent two meal tests: a mixed meal test (MMT) with a carb content of 30 g and a meal test with the low GI supplement, Glucerna SR 1.5® (Glucerna meal test (GMT)). Plasma glucose and serum insulin levels were measured for a period of 6 h.

RESULTS

Peak glucose levels were reached at T 30 during GMT and at T 60 during MMT, and they were 1.5 ± 0.3 mmol/L lower during GMT than during MMT (7.5 ± 0.4 vs 9.0 ± 0.4 mmol/L, P < 0.005). GMT induced the most rapid rise in plasma insulin: at T 30 plasma, insulin was 30.7 ± 8.5 mU/L higher during GMT than during MMT (P < 0.005). None of the carb-restricted meals induced post-prandial hypoglycemia.

CONCLUSION

A 30-g carb-restricted meal may help to prevent post-prandial hypoglycemia in patients with post-RYGB hypoglycemia. The use of a liquid, low GI, supplement offers no additional advantage.

GLP1 and glucagon co-secreting pancreatic neuroendocrine tumor presenting as hypoglycemia after gastric bypass

Post-prandial hypoglycemia is frequently found after bariatric surgery. Although rare, pancreatic neuroendocrine tumors (pNET), which occasionally are mixed hormone secreting, can lead to atypical clinical manifestations, including reactive hypoglycemia. Two years after gastric bypass surgery for the treatment of severe obesity, a 54-year-old female with previous type 2 diabetes, developed post-prandial sweating, fainting and hypoglycemic episodes, which eventually led to the finding by ultrasound of a 1.8-cm solid mass in the pancreatic head. The 72-h fast test and the plasma chromogranin A levels were normal but octreotide scintigraphy showed a single focus of abnormal radiotracer uptake at the site of the nodule. There were no other clinical signs of hormone secreting pNET and gastrointestinal hormone measurements were not performed. The patient underwent surgical enucleation with complete remission of the hypoglycemic episodes. Histopathology revealed a well-differentiated neuroendocrine carcinoma with low-grade malignancy with positive chromogranin A and glucagon immunostaining. An extract of the resected tumor contained a high concentration of glucagon (26.707 pmol/g tissue), in addition to traces of GLP1 (471 pmol/g), insulin (139 pmol/g) and somatostatin (23 pmol/g). This is the first report of a GLP1 and glucagon co-secreting pNET presenting as hypoglycemia after gastric bypass surgery. Although pNET are rare, they should be considered in the differential diagnosis of the clinical approach to the post-bariatric surgery hypoglycemia patient.

LEARNING POINTS

pNETs can be multihormonal-secreting, leading to atypical clinical manifestations.Reactive hypoglycemic episodes are frequent after gastric bypass.pNETs should be considered in the differential diagnosis of hypoglycemia after bariatric surgery.

The Diagnosis and Management of Hyperinsulinaemic Hypoglycaemia

Insulin secretion from pancreatic β-cells is tightly regulated to keep fasting blood glucose concentrations within the normal range (3.5-5.5 mmol/L). Hyperinsulinaemic hypoglycaemia (HH) is a heterozygous condition in which insulin secretion becomes unregulated and its production persists despite low blood glucose levels. It is the most common cause of severe and persistent hypoglycaemia in neonates and children. The most severe and permanent forms are due to congenital hyperinsulinism (CHI). Recent advances in genetics have linked CHI to mutations in 9 genes that play a key role in regulating insulin secretion (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A and HNF1A). Histologically, CHI can be divided into 3 types; diffuse, focal and atypical. Given the biochemical nature of HH (non-ketotic), a delay in the diagnosis and management can result in irreversible brain damage. Therefore, it is essential to diagnose and treat HH promptly. Advances in molecular genetics, imaging methods (18F-DOPA PET-CT), medical therapy and surgical approach (laparoscopic surgery) have completely changed the management and improved the outcome of these children. This review provides an overview of the genetic and molecular mechanisms leading to development of HH in children. The article summarizes the current diagnostic methods and management strategies for the different types of CHI.

Endocrine and metabolic complications after bariatric surgery

Bariatric surgery is the most effective therapeutic option for obese patients; however, it carries substantial risks, including procedure-related complications, malabsorption, and hormonal disturbance. Recent years have seen an increase in the bariatric surgeries performed utilizing either an independent or a combination of restrictive and malabsorptive procedures. We review some complications of bariatric procedures more specifically, hypoglycemia and osteoporosis, the recommended preoperative assessment and then regular follow up, and the therapeutic options. Surgeon, internist, and the patient must be aware of the multiple risks of this kind of surgery and the needed assessment and follow up.

Post-gastric-bypass hypoglycemia successfully treated with alpha-glucosidase inhibitor therapy

OBJECTIVE

To review the effectiveness of alpha-glucosidase inhibitor (AGI) therapy in the treatment of hypoglycemia after Roux-en-y gastric surgery.

METHODS

Retrospective case review.

RESULTS

Four patients who previously underwent Roux-en-y gastric bypass were evaluated because of severe symptomatic postprandial hypoglycemia that was unresponsive to a low-carbohydrate diet. Mixed-meal testing confirmed hyperinsulinemia. Other causes of hypoglycemia were ruled out by a combination of clinical examination, endocrine testing, and computed tomography imaging. Symptomatic hypoglycemia resolved in all 4 patients after AGI therapy was started. One patient could not tolerate long-term therapy because of a rash. The other 3 patients were followed for between 5 and 48 months and remained free of symptomatic postprandial hypoglycemia.

CONCLUSION

AGI therapy is effective in the long-term treatment of post-Roux-en-y hypoglycemia in patients unresponsive to a low-carbohydrate diet. To our knowledge, this is the first report documenting the long-term usefulness of this therapy in a series of patients.

Postprandial hyperinsulinemic hypoglycemia after gastric bypass surgical treatment

An association between post-Roux-en-Y gastric bypass (RYGB) hypoglycemia and nesidioblastosis was reported in 2005 and may cause serious neuroglycopenic symptoms. Most patients with postprandial hypoglycemia after RYGB respond to nutritional and medical treatment. A subset of patients, however, may not respond adequately and surgery may be considered. This review describes the current experience with surgical intervention for severe post-RYGB hypoglycemia. PubMed and MEDLINE searches were made for reports describing clinical outcome after such surgery. Fourteen papers including 75 patients were identified. Different surgical interventions were applied including gastric tube placement, reversal of the bypass with and without concomitant sleeve resection, gastric pouch restriction, and pancreatic resection and reresection. Pancreatic resection was performed in 51 (68%) patients, 17 (23%) had RYGB reversal and eleven (15%) had gastric pouch restriction alone. Eight (11%) patients received 2 or more consecutive procedures for hypoglycemia and combined interventions were made in several patients. Resolution of the symptoms occurred in 34/51 (67%) patients after pancreatic resection, 13/17 (76%) after reversal, and 9/11 (82%) after pouch restriction. Mean follow up, however, was short for most series and the methods applied for evaluation of hypoglycemia varied. Weight regain, diabetes and recurrent symptoms were late complications. The optimal therapy for hypoglycemia after RYGB is not defined. Long-term evaluations and knowledge about the physiology of post-RYGB hypoglycemia, may enable therapy with improved control of the glucose excursions.

Assessment of pancreatic β-cell function: review of methods and clinical applications

Type 2 diabetes mellitus (T2DM) is characterized by a progressive failure of pancreatic β-cell function (BCF) with insulin resistance. Once insulin over-secretion can no longer compensate for the degree of insulin resistance, hyperglycemia becomes clinically significant and deterioration of residual β-cell reserve accelerates. This pathophysiology has important therapeutic implications. Ideally, therapy should address the underlying pathology and should be started early along the spectrum of decreasing glucose tolerance in order to prevent or slow β-cell failure and reverse insulin resistance. The development of an optimal treatment strategy for each patient requires accurate diagnostic tools for evaluating the underlying state of glucose tolerance. This review focuses on the most widely used methods for measuring BCF within the context of insulin resistance and includes examples of their use in prediabetes and T2DM, with an emphasis on the most recent therapeutic options (dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists). Methods of BCF measurement include the homeostasis model assessment (HOMA); oral glucose tolerance tests, intravenous glucose tolerance tests (IVGTT), and meal tolerance tests; and the hyperglycemic clamp procedure. To provide a meaningful evaluation of BCF, it is necessary to interpret all observations within the context of insulin resistance. Therefore, this review also discusses methods utilized to quantitate insulin-dependent glucose metabolism, such as the IVGTT and the euglycemic-hyperinsulinemic clamp procedures. In addition, an example is presented of a mathematical modeling approach that can use data from BCF measurements to develop a better understanding of BCF behavior and the overall status of glucose tolerance.

Bariatric emergencies: current evidence and strategies of management

BACKGROUND

The demand for bariatric surgery is increasing and the postoperative complications are seen more frequently. The aim of this paper is to review the current outcomes of bariatric surgery emergencies and to formulate a pathway of safe management.

METHODS

The PubMed and Google search for English literatures relevant to emergencies of bariatric surgery was made, 6358 articles were found and 90 papers were selected based on relevance, power of the study, recent papers and laparoscopic workload. The pooled data was collected from these articles that were addressing the complications and emergency treatment of bariatric patients. 830,998 patients were included in this review.

RESULTS

Bariatric emergencies were increasingly seen in the Accident and Emergency departments, the serious outcomes were reported following complex operations like gastric bypass but also after gastric band and the causes were technical errors, suboptimal evaluation, failure of effective communication with bariatric teams who performed the initial operation, patients factors, and delay in the presentation. The mortality ranged from 0.14%-2.2% and increased for revisional surgery to 6.5% (p = 0.002). Inspite of this, mortality following bariatric surgery is still less than that of control group of obese patients (p = value 0.01).

CONCLUSIONS

Most mortality and catastrophic outcomes following bariatric surgery are preventable. The awareness of bariatric emergencies and its effective management are the gold standards for best outcomes. An algorithm is suggested and needs further evaluation.

Laparoscopic adjustable gastric banding and hypoglycemia

Obesity is commonplace, and surgical treatment usually includes Roux-en-Y gastric bypasses (RYGBs). RYGBs have the most documented side effects including vitamin deficiencies, rebound weight gain, and symptomatic hypoglycemia; fewer series exist describing hypoglycemia following other bariatric operations. We reviewed all patients undergoing laparoscopic adjustable gastric banding (LAGB) at our institution between 2008 and 2012. Three patients were identified to have symptomatic hypoglycemia following LAGB. Mean time from surgery was 33 months (range 14–45 months), and mean weight loss was 32.7 kg (range 15.9–43.1 kg). None of the patients had preexisting diabetes. Therefore, symptomatic hypoglycemia should be investigated irrespective of bariatric operation.

Laparoscopic sleeve gastrectomy for morbid obesity and glucose metabolism: a new perspective

BACKGROUND

Global rise in the incidence of obesity and type 2 diabetes mellitus is widely recognized as one of the most challenging contemporary threats to public health. Weight loss surgery has proven to be an effective and durable solution for morbidly obese adults. Laparoscopic sleeve gastrectomy (LSG) was introduced as a restrictive procedure for obese patients, initially described as a possible first-stage operation, but now commonly performed as a stand-alone bariatric operation for both high-risk and super-morbid-obese patients, as well as for patients with lower body mass index. This study aims to evaluate the progression of glucose metabolism in patients undergoing LSG.

METHODS

This prospective study investigated 62 patients who underwent LSG by the same surgical team in an 18-month period. Preoperative evaluation included demographic information, complete medical history including comorbidities and medication, clinical examination, evaluation of cardiopulmonary function, measurement of weight and height on a standard electronic scale, upper gastrointestinal endoscopy and upper abdominal ultrasound, as well as interviews with a psychologist and nutritionist. Glucose metabolism was evaluated by oral glucose tolerance test (OGTT), preoperatively and at 3, 6, and 12 months after surgery.

RESULTS

The OGTT was significantly ameliorated in all groups during follow-up. Nine of 12 diabetic patients (75 %) ceased drug treatment at 3 months postoperatively (p = 0.004), increasing to 100 % at 1-year follow-up (p < 0.001). Normoglycemic patients and patients with borderline OGTT experienced mild or severe hypoglycemia during the glucose tolerance test at 3, 6, and 12 months' follow-up.

CONCLUSIONS

LSG offers excellent results to morbidly obese patients with regard to type 2 diabetes mellitus. Implementation of OGTT in these patients can be a valuable tool in their postoperative management. Bariatric teams performing LSG for morbid obesity should heighten their sensitivity to postoperative hypoglycemia, even in patients with type 2 diabetes mellitus.

Moral challenges with surgical treatment of type 2 diabetes

AIM

To review the most important moral challenges following from the widespread use of bariatric surgery for type 2 diabetes for patients with BMI <35kg/m(2), although high quality evidence for its short and long term effectiveness and safety is limited.

METHODS

Extensive literature search to identify and analyze morally relevant issues. A question based method in ethics was applied to facilitate assessment and decision making.

RESULTS

Several important moral issues were identified: assessing and informing about safety, patient outcomes, and stakeholder interests; acquiring valid informed consent; defining and selecting outcome measures; stigmatization and discrimination of the patient group, as well as providing just distribution of health care. The main sources of these challenges are lack of high quality evidence, disagreement on clinical indications and endpoints, and the disciplining of human behavior by surgical interventions.

CONCLUSION

A lack of high quality evidence on the effect of bariatric surgery for the treatment of T2DM in patients with BMI<35/kg/m(2) poses a wide variety of moral challenges, which are important for decisions on the individual patient level, on the management level, and on the health policy making level. Strong preferences among surgeons and patients may hamper high quality research.

Hyperinsulinaemic hypoglycaemia:genetic mechanisms, diagnosis and management

Hyperinsulinaemic hypoglycaemia (HH) is characterized by unregulated insulin secretion from pancreatic β-cells. Untreated hypoglycaemia in infants can lead to seizures, developmental delay, and subsequent permanent brain injury. Early identification and meticulous managementof these patients is vital to prevent neurological insult. Mutations in eight different genes (ABCC8, KCNJ11, GLUD1, CGK, HADH, SLC16A1, HNF4A and UCP2) have been identified to date in patients with congenital forms of hyperinsulinism (CHI). The most severe forms of CHI are due to mutations in ABCC8 and KCJN11, which encode the two components of pancreatic β-cell ATP-sensitive potassium channel. Recent advancement in understanding the genetic aetiology, histological characterisation into focal and diffuse variety combined with improved imaging (such as fluorine 18 L-3, 4-dihydroxyphenylalanine positron emission tomography 18F-DOPA-PET scanning) and laparoscopic surgical techniques have greatly improved management. In adults, HH can be due to an insulinoma, pancreatogenous hypoglycaemic syndrome, post gastric-bypass surgery for morbid obesity as well as to mutations in insulin receptor gene. This review provides an overview of the molecular basis of CHI and outlines the clinical presentation, diagnostic criteria, and management of these patients.

Hyperinsulinaemic hypoglycaemia: genetic mechanisms, diagnosis and management

Hyperinsulinaemic hypoglycaemia (HH) is due to the unregulated secretion of insulin from pancreatic β-cells. A rapid diagnosis and appropriate management of these patients is essential to prevent the potentially associated complications like epilepsy, cerebral palsy and neurological impairment. The molecular basis of HH involves defects in key genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, HNF4A and UCP2) which regulate insulin secretion. The most severe forms of HH are due to loss of function mutations in ABCC8/KCNJ11 which encode the SUR1 and KIR6.2 components respectively of the pancreatic β-cell K(ATP) channel. At a histological level there are two major forms (diffuse and focal) each with a different genetic aetiology. The diffuse form is inherited in an autosomal recessive (or dominant) manner whereas the focal form is sporadic in inheritance and is localised to a small region of the pancreas. The focal form can now be accurately localised pre-operatively using a specialised positron emission tomography scan with the isotope Fluroine-18L-3, 4-dihydroxyphenyalanine (18F-DOPA-PET). Focal lesionectomy can provide cure from the hypoglycaemia. However the diffuse form is managed medically or by near total pancreatectomy (with high risk of diabetes mellitus). Recent advances in molecular genetics, imaging with 18F-DOPA-PET/CT and novel surgical techniques have changed the clinical approach to patients with HH.