Hypoglycemia or non-hypoglycemia

Role of the Entero-Insular Axis in the Pathogenesis of Idiopathic Reactive Hypoglycemia: A Pilot Study

CONTEXT

Idiopathic reactive hypoglycemia (IRH) is characterized by recurrent episodes of symptomatic hypoglycemia occurring within 4 hours after meals. The underlying mechanisms remain obscure.

OBJECTIVE

This study aimed to investigate the response of the glucoregulatory and gastrointestinal hormones to an oral glucose load (OGTT) in individuals with documented IRH.

DESIGN AND SETTING

This was a cross-sectional study composed of outpatients referred to "Federico II" University of Naples.

PATIENTS

We enrolled subjects with IRH documented by a mixed meal under ordinary life conditions and healthy subjects as controls.

MAIN OUTCOME MEASURE

We measured plasma glucose, insulin, glucagon-like peptide 1 (GLP-1), GIP, and glucagon response to a 75-g OGTT in cases and controls.

RESULTS

Ten IRH and eight control subjects were enrolled. During the OGTT, mean plasma glucose tended to be lower in IRH than in control subjects, reaching a statistically significant difference at 240 minutes (T240) (43 ± 1.6 vs 72 ± 0.3 mg/dL; P = .001). Accordingly, the insulin response was higher in IRH than in control subjects (P < .019) with a statistically significant difference (46%) at T90 (P = .045) and was associated with significantly lower glucagon levels in the late phase of the OGTT: at T120 (P = .031) and T180 (P = .048) in IRH than in control subjects. A greater GLP-1 response was found among IRH compared with control subjects (P = .005); GLP-1 peak was 2-fold higher in IRH individuals (9.77 ± 2.52 pmol/L) than in the control group (4.19 ± 0.53 pmol/L; P = .041). In the IRH group, GLP-1 peak inversely correlated with the nadir of plasma glucose (r = -0.66; P = .039). A multivariate analysis confirmed that GLP-1 peak independently predicted the plasma glucose nadir (β = -0.593; P = .026).

CONCLUSIONS

GLP-1 may play a significant role in the pathogenesis of idiopathic IRH.

Postprandial reactive hypoglycaemia in a very old patient

OBJECTIVE AND IMPORTANCE

Postprandial reactive hypoglycaemia (PRH) is a clinical syndrome characterized by the recurrence of symptomatic hypoglycaemia during postprandial periods. PRH remains a diagnostic challenge for clinicians, because of its atypical manifestations and low prevalence, especially in older persons.

CLINICAL PRESENTATION

We report the diagnostic work-up of severe hypoglycaemic episodes in a very old patient in whom the diagnosis of PRH was made.

INTERVENTION

We prescribed acarbose, an alpha-glucosidase inhibitor, to this patient to prevent the recurrence of hypoglycaemic episodes. Four years later, acarbose was always used and no further episode of hypoglycaemia had occurred. Based on the literature, we discuss the limited value of endocrine tests as well as the efficacy of the therapeutic approaches.

CONCLUSION

Prescription of acarbose is useful in addition to nutritional education, the corner stone of the treatment, to avoid the recurrence of severe hypoglycaemic events due to PRH.

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.