Cognition in patients with post-bariatric hypoglycemia

OBJECTIVE

Bariatric surgery, a highly effective treatment for obesity and associated comorbidities, may improve cognition and brain volume in parallel with cardiometabolic function. However, some post-bariatric individuals develop post-bariatric hypoglycemia (PBH), which can be frequent and severe. The impact of recurrent hypoglycemia on cognition in PBH is unknown. The objective of this study was to determine whether individuals with PBH display reduced cognitive function compared with postsurgical counterparts without hypoglycemia.

METHODS

Fourteen adults with a history of Roux-en-Y gastric bypass with hypoglycemia (PBH+, n = 7) or without PBH (PBH-, n = 7) completed assessments of memory, executive function, attention, and psychomotor speed.

RESULTS

PBH+ individuals displayed significantly decreased performance in category fluency (p < 0.01), category switching (p < 0.01), and category switching accuracy (p < 0.01), compared with PBH- individuals. Performance in the first (p = 0.03) and third intervals (p = 0.045) of verbal fluency was significantly lower in PBH+ individuals versus PBH- individuals. All other assessments did not differ.

CONCLUSIONS

PBH+ individuals may be at greater risk for cognitive impairment compared with PBH- individuals, as suggested by impaired semantic processing and cognitive flexibility, as well as greater difficulty initiating and sustaining word retrieval.

Postbariatric surgery hypoglycemia: Nutritional, pharmacological and surgical perspectives

Post-bariatric hypoglycaemia (PBH) is a metabolic complication of bariatric surgery (BS), consisting of low post-prandial glucose levels in patients having undergone bariatric procedures. While BS is currently the most effective and relatively safe treatment for obesity and its complications, the development of PBH can significantly impact patients' quality of life and mental health. The diagnosis of PBH is still challenging, considering the lack of definitive and reliable diagnostic tools, and the fact that this condition is frequently asymptomatic. However, PBH's prevalence is alarming, involving up to 88% of the post-bariatric population, depending on the diagnostic tool, and this may be underestimated. Given the prevalence of obesity soaring, and an increasing number of bariatric procedures being performed, it is crucial that physicians are skilled to diagnose PBH and promptly treat patients suffering from it. While the milestone of managing this condition is nutritional therapy, growing evidence suggests that old and new pharmacological approaches may be adopted as adjunct therapies for managing this complex condition.

Mixed Meal Tolerance Test Versus Continuous Glucose Monitoring for an Effective Diagnosis of Persistent Post-Bariatric Hypoglycemia

Gastric bypass determines an increase in incretin secretion and glucose excursions throughout the day and may sometimes entail the development of severe post-bariatric hypoglycemia (PBH). However, there is no consensus on the gold standard method for its diagnosis. In this study, we evaluated the usefulness of a mixed meal tolerance test (MMTT) and continuous glucose monitoring (CGM) for the diagnosis of PBH, defined as glucose levels <54 mg/dL (3.0 mmol/L). We found that hypoglycemia occurred in 60% of patients after the MMTT and in 75% during CGM, and it was predominantly asymptomatic. The MMTT confirmed the diagnosis of PBH in 88.9%of patients in whom surgery had been performed more than three years ago, in comparison to 36.4% in cases with a shorter postsurgical duration. CGM diagnosed nocturnal asymptomatic hypoglycemia in 70% of patients, and daytime postprandial hypoglycemia in 25% of cases. The mean duration of asymptomatic hypoglycemia was more than 30 min a day. Patients with ≥2% of their CGM readings with hypoglycemia exhibited a higher degree of glucose variability than those with <1% of the time in hypoglycemia. Our results show that the MMTT may be a useful dynamic test to confirm the occurrence of hypoglycemia in a large number of patients with persistent and recurrent PBH during long-term follow-up after gastric bypass. CGM, on its part, helps identify hypoglycemia in the real-world setting, especially nocturnal asymptomatic hypoglycemia, bringing to light that PBH is not always postprandial.

Workup and Management of Recurrent Attacks of Post-bariatric Hypoglycemia in a Patient With Non-alcoholic Steatohepatitis

Bariatric surgery is an established treatment option for patients with non-alcoholic fatty liver disease (NAFLD) as well as non-alcoholic steatohepatitis (NASH) and is said to effectively reduce hepatic inflammation as well as steatosis in these patients. However, bariatric surgery is associated with multiple complications, including nutritional deficiencies, malnutrition, post-bariatric hypoglycemia (PBH), anastomotic leaks, and bowel strictures. This case report describes a rare but significant complication of post-bariatric surgery hypoglycemia in a patient with NASH, which started almost six months after Roux-en-Y gastric bypass (RYGB) surgery. This 55-year-old male patient presented with recurrent episodes of severe hypoglycemia, which, on further work-up, were found to be predominantly nocturnal as well as occurring two to three hours after meals. We report the successful treatment of the patient with an unconventional approach using nifedipine and acarbose. Our findings emphasize the importance of careful evaluation of patients who have undergone bariatric surgery, as this complication can occur as early as six months following the bariatric surgery as well as several years after the surgery. Our case report highlights the need for early recognition, relevant workup, and appropriate management of resistant hypoglycemic events using calcium channel blockers and acarbose, thus adding to the existing literature on this topic.

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.

Uncooked cornstarch for the prevention of hypoglycemic events

Hypoglycemia is a pathological condition characterized by a low plasma glucose concentration associated with typical autonomic and/or neuroglycopenic symptoms, and resolution of these symptoms with carbohydrate consumption. Hypoglycemia is quite common in clinical practice, particularly in insulin-treated patients with diabetes and in other inherited or acquired conditions involving the regulation of glucose metabolism. Beyond symptoms that might strongly affect the quality of life, hypoglycemia can lead to short- and long-term detrimental consequences for health. Hypoglycemia can be prevented by appropriate changes in dietary habits or by relevant modifications of the drug treatment. Several dietary approaches based on the intake of various carbohydrate foods have been tested for hypoglycemia prevention; among them uncooked cornstarch (UCS) has demonstrated a great efficacy. In this narrative review, we have summarized the current evidence on the UCS usefulness in some conditions characterized by high hypoglycemic risk, focusing on some inherited diseases -i.e. glycogen storage diseases and other rare disorders - and acquired conditions such as type 1 diabetes, postprandial hypoglycemia consequent to esophageal-gastric or bariatric surgery, and insulin autoimmune syndrome. We also considered the possible role of UCS during endurance exercise performance. Lastly, we have discussed the dose requirement, the side effects, the limitations of UCS use, and the plausible mechanisms by which UCS could prevent hypoglycemia.

Hypoglycemia After Upper Gastrointestinal Surgery: Clinical Approach to Assessment, Diagnosis, and Treatment

CONTEXT

Post-bariatric hypoglycemia (PBH) is an increasingly encountered complication of upper gastrointestinal surgery; the prevalence of this condition is anticipated to rise given yearly increases in bariatric surgical procedures. While PBH is incompletely understood, there is a growing body of research describing the associated factors, mechanisms, and treatment approaches for this condition.

EVIDENCE ACQUISITION

Data are integrated and summarized from studies of individuals affected by PBH and hypoglycemia following upper gastrointestinal surgery obtained from PubMed searches (1990-2020).

EVIDENCE SYNTHESIS

Information addressing etiology, incidence/prevalence, clinical characteristics, assessment, and treatment were reviewed and synthesized for the practicing physician. Literature reports were supplemented by clinical experience as indicated, when published data were not available.

CONCLUSION

PBH can be life-altering and severe for a subset of individuals. Given the chronic nature of this condition, and sequelae of both acute and recurrent episodes, increasing provider awareness of both the condition and associated risk factors is critical for assessment, prompt diagnosis, treatment, and preoperative identification of individuals at risk.

SYMPTOMATIC AND ASYMPTOMATIC HYPOGLYCEMIA POST THREE DIFFERENT BARIATRIC PROCEDURES: A COMMON AND SEVERE COMPLICATION

Background: The prevalence of post-bariatric surgery hypoglycemia (PBH) remains unclear due to diagnostic criteria variability, types of bariatric procedures and possible unawareness. Objective: To determine the frequency, pattern and severity of symptomatic and asymptomatic hypoglycemia in subjects post three different bariatric procedures performed >1 year before evaluation and a group of obese subjects before surgery. Design and Setting: Observational cohort study. Fifty-one consecutive patients participated: post Roux-en-Y gastric-bypass (RYGB) (n=16), post omega-loop gastric-bypass (OLGB) (n=12), post sleeve-gastrectomy (SG) (n=15), obese subjects before surgery (controls) (n=8). Hypoglycemic events (glucose ≤54 mg/dL) and severe hypoglycemia (glucose ≤40 mg/dL) were evaluated by symptoms' questionnaire, mixed-meal tolerance test (MMTT) and continuous glucose monitoring (CGM). Results: According to questionnaires, meal-related complaints were reported in 11 (26%) of the surgical group and in one control subject. During MMTT, 88%, 82% and 67% experienced hypoglycemia in RYGB, OMGB and SG groups, respectively, vs. none of the controls (P<0.001). Severe hypoglycemia occurred in 38%, 45% and 7% in RYGB, OMGB and SG groups, respectively (P=0.025), but only 10 of the total operated patients (24%) reported any symptoms. During CGM, fasting hypoglycemic events occurred more in RYGB and OLGB vs. SG group: 55%, 63% and 17% respectively (P=0.036). Conclusions: PBH is very common after RYGB, OMGB and SG and can be severe especially following bypass procedures. Our results show that hypoglycemia occurs not only postprandially but also in the fasting state, especially following bypass procedures. In most cases, there were no specific complaints, possibly leading to its underestimation.

Implementation of Low Glycemic Index Diet Together with Cornstarch in Post-Gastric Bypass Hypoglycemia: Two Case Reports

Post-bariatric hypoglycemia (PBH) is an increasingly recognized long-term complication of bariatric surgery. The nutritional treatment of PBH includes a high-fiber diet and the restriction of soluble and high-glycemic index carbohydrates; however, these measures are not always enough to prevent hypoglycemia. We evaluated the efficacy of uncooked cornstarch, a low-glycemic index carbohydrate characterized by slow intestinal degradation and absorption, in addition to a high-fiber diet, for the treatment of PBH. We report the cases of two young women suffering from severe postprandial and fasting hypoglycemia following Roux-en-Y gastric bypass (RYGB). The patients underwent Continuous Glucose Monitoring (CGM) before and 12–16 weeks after the administration of uncooked cornstarch (respectively 1.25 g/kg b.w. and 1.8 g/kg b.w.) in addition to a high-fiber diet. In both patients, CGM showed more stable glucose levels throughout monitoring, a remarkable reduction of the time spent in hypoglycemia (<55 mg/dL) both during the day (−11% for both patients) and the night (−22% and −32%), and the improvement of all glycemic variability indexes. Our report, within the limit of only two cases, suggests that the implementation of a dietary intervention through the addition of uncooked cornstarch reduces daily glycemic fluctuations and hypoglycemic episodes in patients with PBH.