Blood glucose measurements during symptomatic episodes in patients with suspected postprandial hypoglycemia

Postprandial hypoglycemia after ileocolic interposition and Billroth-II gastrojejunostomy: A case report

Postprandial reactive hypoglycemia, or late dumping syndrome, is a common but underrecognized complication from bypass surgery. We report an unusual case of postprandial reactive hypoglycemia in a patient with a severe esophageal stricture from corrosive agent ingestion who underwent ileocolic interposition and an antecolic Billroth-II gastrojejunostomy. A 22-year-old male patient with a one-year history of corrosive ingestion was referred to the hospital for a surgical correction of severe esophageal stricture. After the patient underwent ileocolic interposition and an antecolic Billroth-II gastrojejunostomy, he experienced multiple episodes of gastroesophageal refluxsymptoms during nasogastric feeding and had onset of hypoglycemic symptoms. His plasma glucose level was 59 mg/dL. After we had intraoperatively re-inserted a jejunostomy tube bypassing the ileocolic interposition, and reintroduced enteral nutrition, his hypoglycemic symptoms resolved. We performed a mixed meal tolerance test by nasogastric tube, but the results did not show postprandial hypoglycemia. Although the specific mechanism is unclear, this case suggests gastroesophageal reflux to the ileal interposition may have caused a state of exaggerated hyperinsulinemic response and rebound hypoglycemia. To the best of our knowledge, we are the first to report case of postprandial hypoglycemia after ileocolic interposition, which may have been caused by exaggerated hyperinsulinemic response due to gastroesophageal reflux to the ileal interposition. This syndrome should be considered in the patient who has had ileocolic interposition surgery and has developed postprandial hypoglycemia.

Glucagon responses to glucose challenge in patients with idiopathic postprandial syndrome

BACKGROUND

Postprandial syndrome is characterized by hunger, weakness and anxiety neurosis occurring after meals. Although abnormal glucagon response has been suggested, inaccuracies of the conventional glucagon measurement method have prevented from precise analysis. Recently, a more reliable dual-antibody sandwich enzyme-linked immunosorbent assay for glucagon has been developed.

METHODS

We conducted a 75 g oral glucose tolerance test (OGTT) extending to 4 hours in 14 patients with idiopathic postprandial syndrome. In addition to blood glucose and insulin, we have measured glucagon concentrations using the novel method and analyzed retrospectively.

RESULTS

Median (lower quartile, upper quartile) of age and BMI were 40 years old (30, 49) and 24.9 (23.1, 26.2), respectively. The OGTT revealed that one patient had a diabetic pattern, and two were glucose intolerant. Fasting insulin was 7.6 μU/mL (6.8, 8.8) and reached 73.7 (54.3, 82.6) at 30 min. Insulin remained elevated until 180 min. The fasting glucagon was 21.1 pg/mL (16.1, 33.8), falling at 60 min to a nadir of 6.9 (3.5, 10.3), one-third of the baseline, then remaining suppressed until 180 min. Furthermore, we have found that two types of glucagon dynamics: one is lower fasting glucagon with further suppression and the other is normal or higher fasting glucagon with subsequent big drop.

CONCLUSIONS

These data suggest that glucagon suppression is stronger in patients with idiopathic postprandial syndrome than in normal subjects previously reported. The present data will contribute to further understanding and future research of this syndrome.

[Reactive hypoglycemia - an interdisciplinary approach of the disease of XXI Century]

Reactive hypoglycemia is characterized by low blood glucose level in non-diabetic patients. It manifests as a syndrome of adrenergic and neuroglycopenic symptoms in the postprandial period, and their resolution occurs after consuming carbohydrates. The etiology of reactive hypoglycemia is not fully understood. It may occur in patients after gastrointestinal surgery due to too fast gastric emptying. Decreases in postprandial glucose are also observed in people with a pre-diabetes condition in which insulin secretion is disturbed. Hypoglycaemia can also be seen in patients with insulin resistance and hyperinsulinism. The aim of this study was to summarize existing knowledge about reactive hypoglycemia - etiology, diagnostic model and treatment.

Hypoglycemic symptoms in the absence of diabetes: Pilot evidence of clinical hypoglycemia in young women

Aims

Clinical visits of non-diabetic patients reporting hypoglycemic symptoms are common in endocrinology practices, but remain understudied and lack clinical definition and evidence-based recommendations for diagnosis or treatment. Our goal was to pilot test the concordance of hypoglycemic symptoms with low glucose values in young non-diabetic individuals.

Methods

We recruited eight individuals who reported regularly experiencing symptoms consistent with hypoglycemia to wear a blinded Dexcom continuous glucose monitor and report symptoms for seven days. We excluded individuals with diabetes or other known causes of hypoglycemia or similar symptoms.

Results

Participants were all women with an average age of 29 years. 25% were African American and 25% had obesity. All participants experienced glucose values ≤ 70 mg/dL and half (4/8) experienced glucose ≤ 54 mg/dL for at least 15 min or 3 consecutive readings. Average time between last meal and reported symptoms was 4.4 h. Lower glucose values were significantly associated with higher odds of experiencing hypoglycemic symptoms 1.15 (CI: 1.07-1.24) for every -5mg/dL, (p < 0.001) from mixed effects models for repeated measures adjusted for age, race, and body mass index. All participants also reported engaging in potentially obesogenic behaviors in order to avoid symptoms.

Conclusions

Individuals with hypoglycemic symptoms in the absence of diabetes experience clinical hypoglycemia, indicating the need to understand the etiology, behavioral responses, and other health risks that might be associated with this understudied condition.

Estimating the population prevalence of diagnosed and undiagnosed diabetes

OBJECTIVE

Health administrative data are frequently used for diabetes surveillance, but validation studies are limited, and undiagnosed diabetes has not been considered in previous studies. We compared the test properties of an administrative definition with self-reported diabetes and estimated prevalence of undiagnosed diabetes by measuring glucose levels in mailed-in capillary blood samples.

RESEARCH DESIGN AND METHODS

A stratified random sample of 6,247 individuals (Quebec province) was surveyed by telephone and asked to mail in fasting blood samples on filter paper to a central laboratory. An administrative definition was applied (two physician claims or one hospitalization for diabetes within a 2-year period) and compared with self-reported diabetes alone and with self-reported diabetes or elevated blood glucose level (≥7 mmol/L). Population-level prevalence was estimated with the use of the administrative definition corrected for its sensitivity and specificity.

RESULTS

Compared with self-reported diabetes, sensitivity and specificity were 84.3% (95% CI 79.3-88.5%) and 97.9% (97.4-98.4%), respectively. Compared with diabetes by self-report and/or glucose testing, sensitivity was lower at 58.2% (52.2-64.6%), whereas specificity was similar at 98.7% (98.0-99.3%). Adjusted for sampling weights, population-level prevalence of physician-diagnosed diabetes was 7.2% (6.3-8.0%). Prevalence of total diabetes (physician-diagnosed and undiagnosed) was 13.4% (11.7-15.0%), indicating that ∼40% of diabetes cases are undiagnosed.

CONCLUSIONS

A substantial proportion of diabetes cases are missed by surveillance methods that use health administrative databases. This finding is concerning because individuals with undiagnosed diabetes are likely to have a delay in treatment and, thus, a higher risk for diabetes-related complications.

Post prandial plasma glucose level less than the fasting level in otherwise healthy individuals during routine screening

During routine screening, some otherwise healthy individuals who showed remarkably lower post prandial (at 2 hour) plasma glucose without any symptom were subjected to extended glucose tolerance test and a few of them to extended post meal tolerance test as well. It was observed that post prandial (at 2 hour) plasma glucose after glucose administration was significantly lower than the fasting level (p<0.05-p<0.001). However, post prandial plasma glucose at 2 hour after their usual meal exhibited a significantly higher level than the fasting and post glucose level (p<0.05-p<0.001). Glucose appears to be a stronger agent than the more natural mixed meal in these individuals in causing post prandial lowering of plasma glucose. Hence, these individuals are to be evaluated with their usual meals before considering further investigations. Like upper limit, there is the need to have a consensus lower limit of reference interval of blood glucose level.

Idiopathic reactive hypoglycaemia - prevalence and effect of fibre on glucose excursions

BACKGROUND

Idiopathic reactive hypoglycaemia (IRH) is a condition characterized by aggravated postprandial glucose excursions in otherwise healthy individuals. We investigated its prevalence and the impact of fibre diet supplementation.

METHODS

First, IRH prevalence was assessed in 362 subjects without a diagnosis of abnormal glucose metabolism through an oral glucose tolerance test (OGTT). IRH was defined by 1 h- or 2 h-glucose ≤3.9 mmol/L or 1 h- or 2 h-glucose < fasting glucose. Second, in a cross-over trial we evaluated effects of 2 weeks with, and without, 20 g fibre (fructose- oligosaccharides) diet supplementation in subjects with IRH. At the end of each 2-week cycle we analysed fasting biomarker levels and conducted a 4 h-OGTT.

RESULTS

IRH was found in 12.4% and a normal glucose tolerance in 56.4% of the participants. The IRH group was characterized by higher fasting (5.3 vs. 5.2 mmol/L, p < 0.05) but lower 2 h- (4.4 vs. 6.5 mmol/L, p < 0.01) glucose levels, whereas age (68 ± 10 vs. 70 ± 9 years) and BMI (24.7 ± 3.3 vs 25.0 ± 3.5 kg/m(2)) were similar. The 2-week fibre diet-supplementation (n = 12, age 56 ± 8 years, 6 females, BMI 25.0 ± 2.9 kg/m(2)) improved both the reactive glucose pattern during the 4 h-OGTT (significantly increased late-onset glucose nadirs and reduced the frequency of glucose ≤3.9 mmol/L [21 to 11, p = 0.04]) and reduced fasting plasma glucose (5.4 ± 0.6 to 5.1 ± 0.5 [p < 0.05]) and total cholesterol (5.3 ± 1.1 to 4.9 ± 1.1 mmol/L [p < 0.04]).

CONCLUSIONS

A reactive glucose pattern following intake of a high glycaemic load is relatively prevalent and this phenomenon could be modulated by dietary fibre supplementation.

Obesity-related cardiovascular risk factors after weight loss: a clinical trial comparing gastric bypass surgery and intensive lifestyle intervention

OBJECTIVE

Weight reduction improves several obesity-related health conditions. We aimed to compare the effect of bariatric surgery and comprehensive lifestyle intervention on type 2 diabetes and obesity-related cardiovascular risk factors.

DESIGN

One-year controlled clinical trial (ClinicalTrials.gov identifier NCT00273104).

METHODS

Morbidly obese subjects (19-66 years, mean (s.d.) body mass index 45.1 kg/m(2) (5.6), 103 women) were treated with either Roux-en-Y gastric bypass surgery (n=80) or intensive lifestyle intervention at a rehabilitation centre (n=66). The dropout rate within both groups was 5%.

RESULTS

Among the 76 completers in the surgery group and the 63 completers in the lifestyle group, mean (s.d.) 1-year weight loss was 30% (8) and 8% (9) respectively. Beneficial effects on glucose metabolism, blood pressure, lipids and low-grade inflammation were observed in both groups. Remission rates of type 2 diabetes and hypertension were significantly higher in the surgery group than the lifestyle intervention group; 70 vs 33%, P=0.027, and 49 vs 23%, P=0.016. The improvements in glycaemic control and blood pressure were mediated by weight reduction. The surgery group experienced a significantly greater reduction in the prevalence of metabolic syndrome, albuminuria and electrocardiographic left ventricular hypertrophy than the lifestyle group. Gastrointestinal symptoms and symptomatic postprandial hypoglycaemia developed more frequently after gastric bypass surgery than after lifestyle intervention. There were no deaths.

CONCLUSIONS

Type 2 diabetes and obesity-related cardiovascular risk factors were improved after both treatment strategies. However, the improvements were greatest in those patients treated with gastric bypass surgery.

[Hypoglycemia and insulinoma]

Insulinomas are rare causes of hypoglycemia. After having ruled out non insulinomatous causes of hypoglycemia in a patient in whom Whipple's triad is documented, hyperinsulinism must be demonstrated biochemically, either during a spontaneous hypoglycemic episode or, more often, during a supervised fast which may be prolonged up to 72 h. A mixed-meal test may also help to diagnose the very rare cases of postprandial hypoglycemia related to non insulinoma pancreatogenic hypoglycemic syndrome (NIPHS) or to some rare insulinomas. Only when diagnosis of hypoglycemic hyperinsulinism is made, the tumor localization process may be initiated. This may be difficult due to the small size of insulinomas (generally < 1 cm). Multimodal approach is necessary. The association of endoscopic ultrasound and CT-scan or MRI seems optimal. Octreoscan will be also performed. First results with a very new technique, the GLP-1 receptor imaging, are promising for localizing very small tumors. This localization aims to allow a sparing surgery; enucleation of benign tumors, if possible, allows a pancreatic tissue preservation in patients with quite normal survival.

Interstitial glucose profile associated with symptoms attributed to hypoglycemia by otherwise healthy women

BACKGROUND

Reports of postprandial symptoms attributed to hypoglycemia by otherwise healthy individuals appear to be relatively common in UK women. Whether these symptoms are related to blood glucose is a contentious issue, which periodic ambulatory blood glucose measurement has failed to resolve.

OBJECTIVE

The authors investigated, using continuous glucose monitoring technology, whether postprandial symptoms are associated with interstitial glucose concentrations (IG) in the hypoglycemic range or with a previous fall in IG.

DESIGN

Thirty healthy nonobese women (age 20-48 y) who reported symptoms attributable to hypoglycemia and 20 nonsymptomatic controls wore a subcutaneous probe in abdominal fat for 4-7 d (median: 5 d) and kept a diet and activity diary during this time.

RESULTS

Twenty women reported postprandial symptoms; 41 episodes were recorded. When symptomatic, IG was < or =3.3 mmol/L in 5% of cases. A significant fall in IG over the preceding 60 min was observed before autonomic symptoms (P < 0.005). The proportion of total energy intake derived from dietary fat in the symptomatic group was higher than that in the controls (P < 0.05). The proportion of total sugars was similar between groups; however, the meal preceding symptoms had a higher percentage of energy derived from total sugars when compared with the individuals' diet over the study period (P < 0.05).

CONCLUSIONS

Most symptoms attributable to hypoglycemia were not associated with an IG concentration in the hypoglycemic range. A previous fall in IG may be implicated in the etiology of autonomic symptoms, with the consumption of meals high in sugars potentially playing a role in symptom initiation.

Ambulatory blood glucose measurement, dietary composition and physical activity levels in otherwise healthy women reporting symptoms that they attribute to hypoglycaemia

Reactive hypoglycaemia (RH) is a condition that has been popularised in the media and lay literature, particularly that targeting women, over the past 30 years. The objective of the present study was to investigate whether a non-patient group reporting symptoms that they attributed to a low blood glucose level would demonstrate biochemical hypoglycaemia when symptomatic and whether their habitual diet and activity level differed from those of controls. Thirty non-obese, healthy women (aged 19–45 years) reporting symptoms more than once a week that they attributed to hypoglycaemia (RH group), and eighteen controls, measured their finger-prick blood glucose level 3h after breakfast and lunch, and recorded their diet and activity daily for 7d. The RH group also measured their blood glucose when symptoms were being experienced. Symptoms less than 4h after eating were classed as postprandial. The mean postprandial blood glucose level in the RH group when asymptomatic (4·66 (sem 0·08) mmol/l) was significantly lower than that of controls (5·05 (sem 0·11) mmol/l; P<0·01). Symptoms occurred 2·6 (sem 0·13) h after eating, at a lower blood glucose level (4·18 (sem 0·10) mmol/l; P<0·001) than when the women were asymptomatic. On symptomatic days, the RH group were more physically active than the controls (1·64 (sem 0·04) v. 1·50 (sem 0·03) multiples of resting energyexpenditure; P<0·05), with a lower energy intake (7901 (sem 311) et al.. 9332 (sem 227) kJ; P<0·001). In conclusion, subjects reporting symptoms they associated with hypoglycaemia generally did not demonstrate biochemical hypoglycaemia but did have significantly lower blood glucose levels than controls. Higher physical activity and a failure to match energy intake to estimated energy requirement may be important in the aetiology of symptoms.

Hypoglycemia

Under physiologic conditions, glucose plays a critical role in providing energy to the central nervous system. A precipitous drop in the availability of this substrate results in dramatic symptoms that signal a medical emergency and warrant immediate therapy aimed at restoring plasma glucose to normal levels. A systemic approach to the differential diagnosis is useful in identifying the cause of hypoglycemia. Once established, a specific and/or definitive intervention that addresses that underlying problem can be implemented. In most cases, this systemic approach to diagnosis and therapy is rewarded with a good outcome for the patient.

Prevalence of self-reported symptoms attributed to hypoglycaemia within a general female population of the UK

OBJECTIVE

To investigate the prevalence of symptoms attributed to hypoglycaemia that are reported by a general female population of the UK.

METHOD

A health and well-being questionnaire, including questions relating to symptoms of low blood 'sugar', medical history and anthropometry, was administered by post to 2000 randomly selected women (17-50 years) in Nottinghamshire. To avoid biasing responses, participants were not made aware of the specific focus of the study.

RESULTS

One thousand one hundred and thirty-six women returned the questionnaire (56.8% response rate). After exclusions, 37.9% of respondents reported symptoms that they attributed to hypoglycaemia, with a median of four episodes reported per month. A significant variation in the reporting of symptoms was found across body mass index (BMI) categories, with the highest prevalence of symptomatic subjects being found at the lowest BMI range (P<.05).

CONCLUSION

More than a third of women in the UK report experiencing symptoms that they attribute to hypoglycaemia. Body mass index appears to be related to the experiencing of symptoms.

Hypoglycemia during the 100-g oral glucose tolerance test: incidence and perinatal significance

OBJECTIVE

To estimate and report the incidence and perinatal significance of hypoglycemia during the 100-g oral glucose tolerance test in pregnant women.

METHODS

Over a 3-year period, we analyzed the incidence and perinatal outcome of pregnant women who experienced hypoglycemia, defined as a plasma glucose level of 50 mg/dL or less while undergoing the 100-g oral glucose tolerance test. The study group included women who delivered singletons at term. Women who underwent the 100-g oral glucose tolerance test during the same period and had no hypoglycemia served as the control group.

RESULTS

A total of 805 women were included in the study, which comprised 51 women (6.3%) who experienced hypoglycemia during the test and 754 women in the control group. Gestational diabetes mellitus was diagnosed in 5/51 (9.8%) women in the study group, compared with 216/754 (28.6%) women in the control group (P < .03), and the neonates born to these women had significantly lower birth weights.

CONCLUSION

The incidence of reactive hypoglycemia during the 100-g oral glucose tolerance test in our population is 6.3%. Women who experience hypoglycemia during the test have a significantly lower incidence of gestational diabetes and neonatal birth weights.

Biochemical hypoglycemia in female nurses during clinical shift work

Female nurses in Japan commonly experience symptoms similar to those of hypoglycemia while working. Biochemical hypoglycemia can lead to impaired cognition; thus, it is important to know the prevalence of biochemical hypoglycemia among nurses. Five hundred and sixty-eight female nurses (53% of the target population) in four hospitals completed questionnaires. They determined their blood glucose levels 12 times, at four points during three shifts. Fifty-seven nurses (10%) recorded biochemical hypoglycemia (<or=3.0 mM) at least once. Multivariate analysis revealed three independent risk factors for hypoglycemia: higher coefficient of variation of blood glucose level, lower body mass index, and not smoking. Subjective symptoms were not associated with hypoglycemia. More research on hypoglycemia is needed in order to improve working environment for nurses.

Classification of hypoglycemic disorders

The classification of symptoms of hypoglycemia, namely, reactive versus fasting, based on segregation by timing in relation to meals is no longer useful from a clinical point of view. Every patient with neuroglycopenic symptoms, regardless of relation to food ingestion, requires comprehensive evaluation. Identification of the possible cause of hypoglycemia and selection of diagnostic modalities are facilitated by considering whether the patient appears to be healthy (with or without compensated coexistent disease) or ill (with a disease known to have a proclivity to develop hypoglycemia, or is hospitalized). Medications may mediate hypoglycemia in anybody, whether they appear healthy or ill.

Hypoglycemia

The diagnosis of a hypoglycemic disorder requires a high level of suspicion, careful assessment of the patient for the presence of mediating drugs or predisposing illness, and, when indicated, methodic evaluation of the basis of well-defined diagnostic criteria. The diagnostic burden is heaviest for healthy-appearing persons with episodes of confirmed neuroglycopenia. The author's criteria for insulin mediation of hypoglycemia are plasma insulin of 6 microU/mL or higher (radioimmunoassay), C-peptide of 200 pmol/L or higher (ICMA), proinsulin of 5 pmol/L or higher (ICMA), beta OH butyrate of 2.7 mmol/L or lower, and generous (> or = 25 mg/dL) response of plasma glucose to intravenous glucagon administered when the patient is hypoglycemic. Sulfonylurea should be sought in the plasma of any hypoglycemic patient, especially by an assay which can detect the second generation of these drugs.

Increased insulin sensitivity and basal insulin effectiveness in postprandial reactive hypoglycaemia

Glucose clamp experiments have shown that patients with reactive postprandial hypoglycaemia (PRH) frequently have an increased glucose disposal, but the relative involvement of insulin sensitivity (SI) and glucose effectiveness (Sg) in this process remains unknown. The minimal model approach was used to compare 13 patients in whom moderate reactive hypoglycaemia ( < 3.3 mmol) had been previously diagnosed and 13 matched controls. The intravenous glucose tolerance test (IVGTT, 0.5 g/kg glucose IV) with 0.02 U/kg insulin given at the 19th min and frequent sampling over 180 min shows that PRH patients exhibit a higher glucose tolerance coefficient Kg (2.99 +/- 0.26 vs 2.19 +/- 0.12; P < 0.02), higher SI [22.9 +/- 6.4 vs 7.18 +/- 0.14 min-1/(microU/ml). 10(-4); P < 0.01] and higher Sg (3.84 +/- 0.35 vs 2.92 +/- 0.79 min-1. 10(-2); P < 0.05). The increase in Sg is explained by an increase in its component basal insulin effectiveness (BIE: 1.2 +/- 0.27 min-1.10(-2) in PRH subjects vs 0.58 +/- 0.07; P < 0.05) rather than an increase in Sg at zero insulin. The increase in BIE results from the high values of SI. In 4 PRH subjects SI and Sg were within the normal range, and the increase in Kg evidenced in the 9 others was explained by an increase in SI alone in 3 cases, in Sg alone in 1 case, and both SI and Sg in 5 cases. Thus, in sedentary subjects, the previously reported rise in tissue glucose assimilation is mainly explained by an increased insulin-mediated glucose disposal rather than non-insulin-mediated glucose disposal.

Determination of glucose levels using dried filter paper blood spots: new perspective in home monitoring

We present a method for the determination of blood glucose using dried filter paper blood spots. To validate this method, we compared our results using filter paper and simultaneously collected venous blood. We demonstrated that there is a linear relationship between the filter paper glucose levels and those determined in whole blood (r = 0.98). There was no significant difference between the results of the two methods (p > 0.05). This method is a cheap alternative which may improve the control of diabetes mellitus, and may also be very useful in the diagnosis of postprandial hypoglycemia and other special situations.

Evaluation of a standardized hyperglucidic breakfast test in postprandial reactive hypoglycaemia

The oral glucose tolerance test is not specific for diagnosing postprandial reactive hypoglycaemia, since it too frequently induces low blood glucose values in subjects who have never complained of symptoms of this. By contrast, the mixed meal tests are deceptive for this purpose because they do not induce hypoglycaemia in subjects who have complained of of hypoglycaemic symptoms. We investigated the frequency of hypoglycaemia after a standardized hyperglucidic breakfast test in three groups of subjects:group A, 43 control subjects; group B, 38 postprandial reactive hypoglycaemic patients; group C, 1193 asymptomatic subjects undergoing assessment of glycoregulation. In the 38 subjects with suspected reactive hypoglycaemia the mean blood glucose nadir was 3.48 +/- 0.08 mmol/l, i.e. lower than in control subjects (4.83 +/- 0.13 p < 0.0001). Blood glucose levels less than 3.3 mmol/l were found in 47.3% of subjects with suspected postprandial reactive hypoglycaemia (group B), i.e more frequently than in control subjects (group A: 2.2% p = 1.6 x 10(-6)) and asymptomatic subjects (group C: 1% p = 8 x 10(-22)). This markedly higher frequency of low blood glucose values in subjects with postprandial symptoms compared with control and asymptomatic subjects suggests that this test detects a tendency to hypoglycaemia after a standardized hyperglucidic breakfast. Since this test mimics average French eating habits, the results suggest that the patients undergo such symptoms in their everyday life, and that the hyperglucidic breakfast test is a simple alternative to ambulatory glucose sampling for diagnosis of postprandial reactive hypoglycaemia.

Hypoglycemia

Hypoglycemia is the most common endocrine medical emergency. Because the brain has an obligatory need for contiunous inflow of glucose, any interruption to that supply puts the individual at risk for neuroglycopenia. The latter impairs brain function and precludes self-administered corrective treatment. Treatment of hypoglycemia, especially in those patients with diabetes mellitus, involves punctilious attention to preventive measures. The acute event, if recognized, requires treatment with oral ingestion of free carbohydrate. Neuroglycopenia can be treated equally effectively with intravenous glucose or parenteral glucagon administration.

The use of acarbose in the prevention and treatment of hypoglycaemia

This paper reviews the use of acarbose in the prevention and treatment of hypoglycaemia. In diet- or sulfonylurea-treated patients, acarbose may reduce the incidence of late postprandial hypoglycaemia. In insulin-treated patients, acarbose treatment usually requires reduction of the insulin dose; one study has shown that 100 mg acarbose at night significantly reduces the incidence of mid-evening and nocturnal hypoglycaemia. Several studies have suggested acarbose to be a useful adjunct to the management of reactive hypoglycaemia in the non-diabetic patients. Long-term prospective studies are still needed to document this last indication of acarbose or other alpha-glycosidase inhibitors.

Prevalence of food allergy and intolerance in the adult Dutch population

The prevalence of food allergy and intolerance (FA/FI) was studied in a random sample (n = 1483) of the Dutch adult population. First, the self-reported FA/FI reactions were investigated by questionnaire. Subsequently, in a clinical follow-up study, it was determined in how many cases this self-reported FA/FI could be objectively confirmed by double-blind placebo-controlled food challenge. More than 10% of the population (12.4%) reported FA/FI to specific food(s). Of the 144 subjects potentially available for the clinical follow-up study, 73 completed the whole protocol. In 12 subjects FA/FI could be confirmed by double-blind placebo-controlled food challenge. This indicates a minimum prevalence of FA/FI in the population of 0.8% (12 of 1483). Assuming that FA/FI is equal among participants, nonparticipants, and dropouts, the prevalence of FA/FI in the Dutch adult population is estimated to be 2.4%. The food (ingredients) involved included pork, white wine, and menthol. Two persons reacted to additives. In three persons glucose intolerance was observed. However, these specific intolerances probably do not reflect the distribution in the general population because the study population formed an extremely heterogeneous group, both with regard to the offending foods and the symptoms. The majority of the subjects had no serious complaints that required medical advice. We conclude that there is a gap between self-reported FA/FI and FA/FI that can be objectively confirmed by double-blind placebo-controlled food challenge.

Hypoglycaemia in the adult

Hypoglycaemia is a relatively common cause for referral of patients to the accident and emergency departments of hospitals but most of it is iatrogenic. Occasionally, however, hypoglycaemia is due to any one of up to a hundred different disorders. In some, hypoglycaemia is the cause of intermittent neuroglycopenic symptoms that lead to their referral to medical outpatients for investigation. Only the most important are discussed here. Hyperinsulinism due to abnormal beta-cell function is an uncommon but important cause of spontaneous hypoglycaemia. The diagnosis is suspected from the history of episodes of altered consciousness confirmed by demonstrating raised plasma insulin, C-peptide and proinsulin levels in peripheral blood in the presence of hypoglycaemia. Differentiation of the various causes of endogenous hyperinsulinism before surgery is difficult if not impossible and the low predictive value of most of the localizing techniques that are available makes them an additional and unnecessary cost, producing little clinical benefit. Hypoglycaemia caused by non-islet cell tumours (NICTH) is seemingly rarer than hyperinsulinism from insulinoma and tends to occur in older patients. The clinical features are similar to those of hyperinsulinism but laboratory investigation reveals appropriately depressed plasma insulin, C-peptide and proinsulin levels in the presence of hypoglycaemia. The plasma IGF-II:IGF-I ratio is characteristically high and the concentration of the E-domain of proIGF-II is raised. Autoimmune hypoglycaemia is more common in some countries than others and is most often due to autoantibodies to insulin (AIS). It may also be caused by autoantibodies to the insulin receptor and possibly to autoantibodies that are stimulatory to pancreatic beta-cells. Contrary to popular belief, idiopathic reactive hypoglycaemia is rare and only one of the possible causes of the postprandial syndrome. It is characterized by a low blood glucose concentration in blood collected during a spontaneous symptomatic episode but not at other times. Its cause is unknown. Other causes of hypoglycaemia include endocrinopathies of various kinds; sepsis including malaria; congestive cardiac failure; hepatic and renal insufficiencies; diverse inborn errors of metabolism; and exogenous toxins, of which alcohol is probably the commonest.

Glycaemic thresholds for hypoglycaemic symptoms, impairment of cognitive function, and release of counterregulatory hormones in subjects with functional hypoglycaemia

Nine patients with food-relieved hypoglycaemic symptoms, in whom insulinoma and other organic diseases presenting with hypoglycaemia had been ruled out, and nine matched controls, participated in the study. Subjects were studied during a 5-h controlled (Biostator) insulin-induced (1-2 mU kg-1 min-1) hypoglycaemic clamp. After 1 h of euglycaemia, we aimed to lower the glucose level in arterialized venous blood in a stepwise manner at 30-min intervals to 3.5, 3.0, and 2.0 mmol l-1, and to withhold these levels for a further 30 min. At euglycaemia and at the end of the latter steps, the visual reaction time and cognitive function (digit span, letter cancellation and trail making) were tested, together with recording symptoms and signs of hypoglycaemia. Counter-regulatory hormones were measured at 20-min intervals. In the patients, clinical signs and symptoms of hypoglycaemia developed at median blood glucose levels of 2.6-2.8 and 2.8-3.1 mmol l-1, respectively. By contrast, the blood glucose levels were 0.4-0.8 mmol l-1 lower in control subjects (P less than 0.05). Similarly, the median threshold for deterioration of visual reaction time was 2.8 mmol l-1 in patients and 2.1 mmol l-1 in controls (P less than 0.01). A similar trend was observed for the results of the neuropsychological tests. Visual reaction time deteriorated in all subjects, whereas the cognitive function of some of the subjects in each group remained unchanged during hypoglycaemia. The glycaemic thresholds for release of cortisol, glucagon and growth hormone were significantly higher in patients (P less than 0.05), whereas the thresholds for catecholamine release showed no significant difference from controls. Despite the comparable glucose infusion rates required to sustain each of the hypoglycaemic levels in the two groups, the control subjects achieved lower glucose levels, suggesting that there is resistance to insulin or glucose in functional hypoglycaemia. In conclusion, the present study suggests that the existence of a higher threshold for symptoms and signs, as well as for deterioration of brain function, may explain every-day hypoglycaemic symptoms, despite normal glucose levels, in subjects with functional hypoglycaemia. However, the hypothesis should be tested further using a blinded approach, including euglycaemic control studies.