Hypoglycemia after gastric bypass: An emerging complication

Diagnosis and management of post-bariatric surgery hypoglycemia

INTRODUCTION

While bariatric surgery remains the most effective treatment for obesity that allows substantial weight loss with improvement and possibly remission of obesity-associated comorbidities, some postoperative complications may occur. Managing physicians need to be familiar with the common problems to ensure timely and effective management. Of these complications, postoperative hypoglycemia is an increasingly recognized complication of bariatric surgery that remains underreported and underdiagnosed.

AREA COVERED

This article highlights the importance of identifying hypoglycemia in patients with a history of bariatric surgery, reviews pathophysiology and addresses available nutritional, pharmacological and surgical management options. Systemic evaluation including careful history taking, confirmation of hypoglycemia and biochemical assessment is essential to establish accurate diagnosis. Understanding the weight-dependent and weight-independent mechanisms of improved postoperative glycemic control can provide better insight into the causes of the exaggerated responses that lead to postoperative hypoglycemia.

EXPERT OPINION

Management of post-operative hypoglycemia can be challenging and requires a multidisciplinary approach. While dietary modification is the mainstay of treatment for most patients, some patients may benefit from pharmacotherapy (e.g. GLP-1 receptor antagonist); Surgery (e.g. reversal of gastric bypass) is reserved for unresponsive severe cases. Additional research is needed to understand the underlying pathophysiology with a primary aim in optimizing diagnostics and treatment options.

Hypoglycemia after bariatric surgery: importance of exhaustive hormonal study

SUMMARY

Hypoglycemia is an uncommon clinical problem in non-diabetic patients or patients not being treated for diabetes mellitus. It is a rare, but well-established complication of bariatric surgery and, in some cases, it can be the only symptom of another medical problem. A 50-year-old woman with a history of partially recovered hypopituitarism after transsphenoidal surgery for a non-functioning pituitary macroadenoma complained about symptomatic hypoglycemia after sleeve gastrectomy surgery. Our initial studies failed to determine the cause for these episodes and treatment with acarbose (suspecting a dumping syndrome) was not helpful. Finally, laboratory findings revealed growth hormone (GH) deficiency. The patient received treatment with GH, with the resolution of symptoms after 3 months of treatment. Our case suggests that all causes of hypoglycemia should be considered and studied after bariatric surgery. An improvement in insulin-resistance following bariatric surgery can trigger clinical manifestations of GH deficiency.

LEARNING POINTS

Postprandial hypoglycemia after bariatric surgery is usually due to dumping syndrome. Even after bariatric surgery, all causes of hypoglycemia should be considered and studied. After significant weight loss, insulin sensitivity is usually restored and can trigger clinical manifestations of GH deficiency. Hypoglycemia is a rare symptom of GH deficiency.

Hypoglycemia After Gastric Bypass Successfully Treated With Calcium Channel Blockers: Two Case Reports

Postprandial hyperinsulinemic hypoglycemia is an uncommon yet well-established complication of Roux-en-Y gastric bypass (RYGB) that can result in serious morbidity and adversely affect quality of life. It is often unrecognized and may be difficult to diagnose. Management is challenging. As the number of bariatric procedures increases in parallel with the obesity epidemic, clinicians will be tasked to offer effective medical therapies for this complication. Two patients presented several years after RYGB with severe postprandial hypoglycemia. In one of the patients, we were able to document simultaneous postprandial hypoglycemia and hyperinsulinemia. Conventional treatment approaches, including medical nutrition therapy, acarbose, diazoxide, and octreotide, were either ineffective or limited by poor tolerance. Nifedipine and verapamil were used adjunctively with dietary modification, resulting in resolution of symptomatic hypoglycemic episodes. These agents are therapeutic options that can be used for some patients refractory to more traditional treatments. They should be tried before surgical procedures are considered for affected patients. These two cases demonstrate that calcium channel blockers may be efficacious and appropriate for select patients refractory to dietary interventions alone.

The benefits of non-surgical weight management on weight and glycaemic control in people with complex type 2 diabetes: A primary care service evaluation of clinical outcomes at 12 months

Optimizing diabetes management in patients with complex type 2 diabetes (T2DM) and obesity presents challenges. This study evaluates weight and HbA1c at 12 months (primary outcomes) and blood pressure, lipids, medication and lifestyle changes (secondary outcomes) in patients referred by a diabetes specialist (DSN) to the weight management intervention (Slimming World). Patients attended up to 12 or 24 funded weekly group sessions. The DSN recorded baseline and 12-month primary and secondary outcome data. A post-intervention questionnaire explored the lifestyle changes made. 69 patients achieved a mean weight loss of 5.5 (5.16) %, reduction in BMI [37.7(6.11) to 35.9 (6.30) kg/m2, P < 0.001] and HbA1c levels [62.8 (12.85) to 55.0 (13.02) mmol/mol, P < 0.001] at 12 months. 81.2% reduced their HbA1c levels. Small reductions were observed in SBP, DBP and triglycerides, and six patients reduced their diabetes medications. Twenty patients completed the questionnaire: unhealthy snacking reduced (P < 0.001) and going for walks increased (P < 0.001) with fewer people avoiding moderate activity (P < 0.05). Despite being a chronic, progressive condition, referral to a community-based programme was successful in supporting patients with established T2DM improve their diet and activity levels, lose weight and improve their glycaemic control 12 months later with a small number able to reduce their medication.

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.

An unusual presentation of post gastric bypass hypoglycemia with both postprandial and fasting hypoglycemia

There has been an increasing awareness of post gastric bypass hypoglycemia (PGBH). Histopathologic findings from such patients who underwent partial/total pancreatomy, however, can vary widely from minimal changes to classic nesidioblastosis, making the pathologic diagnosis challenging. PGBH typically presents as postprandial hypoglycemia, as opposed to insulinoma, which presents as fasting hypoglycemia. Herein, we describe an unusual case of a patient with PGBH who initially presented with postprandial hypoglycemia three years after surgery, but later developed fasting hyperinsulinemic hypoglycemia as the disease progressed. Our hypothesis for this phenomenon is that this disease is progressive, and later in its course, the insulin release becomes dissociated from food stimulation and is increased at baseline. Future studies are needed to investigate the prevalence as well as etiology of this progression from postprandial to fasting hypoglycemia. Learning points: •• There has been an increasing awareness of post gastric bypass hypoglycemia (PGBH). •• Histopathologically, PGBH can vary from minimal changes to nesidioblastosis. •• Although uncommon, patients with PGBH after Roux-en-Y gastric bypass may present with both postprandial and fasting hyperinsulinemic hypoglycemia as disease progresses. •• Our hypothesis for this phenomenon is that the insulin release becomes dissociated from food stimulation and is increased at baseline with disease progression.