Sweet dreams?--nocturnal hypoglycemia in children with type 1 diabetes

Hypoglycemia Unawareness-A Review on Pathophysiology and Clinical Implications

Hypoglycemia is a particular problem in people with diabetes while it can also occur in other clinical circumstances. Hypoglycemia unawareness describes a condition in which autonomic and neuroglycopenic symptoms of hypoglycemia decrease and hence are hardly perceivable. A failure to recognize hypoglycemia in time can lead to unconsciousness, seizure, and even death. The risk factors include intensive glycemic control, prior episodes of severe hypoglycemia, long duration of diabetes, alcohol consumption, exercise, renal failure, and sepsis. The pathophysiological mechanisms are manifold, but mainly concern altered brain glucose sensing, cerebral adaptations, and an impaired hormonal counterregulation with an attenuated release of glucagon, epinephrine, growth hormone, and other hormones, as well as impaired autonomous and neuroglycopenic symptoms. Physiologically, this counterregulatory response causes blood glucose levels to rise. The impaired hormonal counterregulatory response to recurrent hypoglycemia can lead to a vicious cycle of frequent and poorly recognized hypoglycemic episodes. There is a shift in glycemic threshold to trigger hormonal counterregulation, resulting in hypoglycemia-associated autonomic failure and leading to the clinical syndrome of hypoglycemia unawareness. This clinical syndrome represents a particularly great challenge in diabetes treatment and, thus, prevention of hypoglycemia is crucial in diabetes management. This mini-review provides an overview of hypoglycemia and the associated severe complication of impaired hypoglycemia awareness and its symptoms, pathophysiology, risk factors, consequences, as well as therapeutic strategies.

Childhood diabetes and sleep

Sleep modulates glucose metabolism, both in healthy states and in disease. Alterations in sleep duration (insufficient and excessive) and obstructive sleep apnea may have reciprocal ties with obesity, insulin resistance and Type 2 diabetes, as demonstrated by emerging evidence in children and adolescents. Type 1 diabetes is also associated with sleep disturbances due to the influence of wide glycemic fluctuations upon sleep architecture, the need to treat nocturnal hypoglycemia, and the need for glucose monitoring and insulin delivery technologies. In this article, we provide an extensive and critical review on published pediatric literature regarding these topics, reviewing both epidemiologic and qualitative data, and provide an overview of the pathophysiology linking sleep with disorders of glucose homeostasis.

Safety issues associated with dietary management in patients with hepatic glycogen storage disease

INTRODUCTION

Hepatic glycogen storage diseases (GSDs) are a group of inherited disorders of carbohydrate metabolism for which dietary management is the cornerstone. Safety and acute complications associated with dietary management have been poorly documented. We hypothesized that safety issues and complications associated with dietary management are prevalent amongst patients with these ultra-rare disorders.

METHODS

A questionnaire was developed consisting of 40 questions and was distributed via eight GSD patient organizations from multiple countries. Respondents were (caregivers of) patients with self-reported hepatic GSD.

RESULTS

249 GSD patients from 26 countries responded with a median age of 14.8 years (range: 0.5-66.1). Although management was considered safe by 71% of patients, 51% reported at least one acute complication associated with dietary management, with a total number of 425 reported complications. Most frequently reported causes were: not waking up by an alarm clock (n = 70), forgetting a meal (n = 57) and infections (n = 43). Most frequently reported complications were: hypoglycemia (n = 112), hospital admissions (n = 79) and drowsiness (n = 74). Most complications occurred before the age of 12 years (82%; 637/774 total number of reported events) and during night time (63%; 340/536). Only 61% (152/249) of the GSD patients reported using a written emergency protocol.

CONCLUSIONS

Safety issues and complications associated with dietary management are prevalently reported by (caregivers of) 249 GSD patients. A discrepancy has been observed between the patient's perspective on safety of dietary management and occurrence of complications as a result of dietary management.

Insulin delivery and nocturnal glucose control in children and adolescents with type 1 diabetes

Introduction: Nocturnal glucose control remains challenging in children and adolescents with type 1 diabetes due to highly variable overnight insulin requirements. The issue may be addressed by glucose responsive insulin delivery based on real-time continuous glucose measurements.

Areas covered: This review outlines recent developments of glucose responsive insulin delivery systems from a paediatric perspective. We cover threshold-based suspend application, predictive low glucose suspend, and more advanced single hormone and dual-hormone closed-loop systems. Approaches are evaluated in relation to nocturnal glucose control particularly during outpatient randomised controlled trials.

Expert opinion: Significant progress translating research from controlled clinical centre settings to free-living unsupervised home studies have been achieved over the past decade. Nocturnal glycaemic control can be improved whilst reducing the risk of hypoglycaemia with closed-loop systems. Following the US regulatory approval of the first hybrid closed-loop system in non-paediatric population, large multinational closed-loop clinical trials and pivotal studies including paediatric populations are underway or in preparation to facilitate the use of closed-loop systems in clinical practice.

Qualitative observation instrument to measure the quality of parent-child interactions in young children with type 1 diabetes mellitus

Background

In young children with type 1 diabetes mellitus (T1DM), parents have complete responsibility for the diabetes-management. In toddlers and (pre)schoolers, the tasks needed to achieve optimal blood glucose control may interfere with normal developmental processes and could negatively affect the quality of parent–child interaction. Several observational instruments are available to measure the quality of the parent–child interaction. However, no observational instrument for diabetes-specific situations is available. Therefore, the aim of the present study was to develop a qualitative observation instrument, to be able to assess parent–child interaction during diabetes-specific situations.

Methods

First, in a pilot study (n = 15), the observation instrument was developed in four steps: (a) defining relevant diabetes-specific situations; (b) videotaping these situations; (c) describing all behaviors in a qualitative observation instrument; (d) evaluating usability and reliability. Next, we examined preliminary validity (total n = 77) by testing hypotheses about correlations between the observation instrument for diabetes-specific situations, a generic observation instrument and a behavioral questionnaire.

Results

The observation instrument to assess parent–child interaction during diabetes-specific situations, which consists of ten domains: “emotional involvement”, “limit setting”, “respect for autonomy”, “quality of instruction”, “negative behavior”, “avoidance”, “cooperative behavior”, “child’s response to injection”, “emphasis on diabetes”, and “mealtime structure”, was developed for use during a mealtime situation (including glucose monitoring and insulin administration).

Conclusions

The present study showed encouraging indications for the usability and inter-rater reliability (weighted kappa was 0.73) of the qualitative observation instrument. Furthermore, promising indications for the preliminary validity of the observation instrument for diabetes-specific situations were found (r ranged between |.24| and |.45| for significant correlations and between |.10| and |.23| for non-significant trends). This observation instrument could be used in future research to (a) test whether parent–child interactions are associated with outcomes (like HbA_1c levels and psychosocial functioning), and (b) evaluate interventions, aimed at optimizing the quality of parent–child interactions in families with a young child with T1DM.

Insulin pump therapy in youth with type 1 diabetes: toward closed-loop systems

INTRODUCTION

Insulin pump technology has advanced considerably over the past three decades, leading to more favorable metabolic control and less hypoglycemic events when compared with multiple daily injection therapy. The use of insulin pumps is increasing, particularly in children and adolescents with type 1 diabetes.

AREAS COVERED

This review outlines recent developments in insulin pump therapy from a pediatric perspective. 'Smart' pumps, sensor-augmented pump therapy and threshold-suspend feature of insulin pumps are reviewed in terms of efficacy, safety and psychosocial impact. The current status of closed-loop systems focusing on clinical outcomes is highlighted.

EXPERT OPINION

Closed-loop insulin delivery is gradually progressing from bench to the clinical practice. Longer and larger studies in home settings are needed to expand on short- to medium-term outpatient evaluations. Predictive low glucose management and overnight closed-loop delivery may be the next applications to be implemented in daily routine. Further challenges include improvements of control algorithms, sensor accuracy, duration of insulin action, integration and size of devices and connectivity and usability. Gradual improvements and increasing sophistication of closed-loop components lie on the path toward unsupervised hands-off fully closed-loop system.

Hypoglycemia: The neglected complication

Hypoglycemia is an important complication of glucose-lowering therapy in patients with diabetes mellitus. Attempts made at intensive glycemic control invariably increases the risk of hypoglycemia. A six-fold increase in deaths due to diabetes has been attributed to patients experiencing severe hypoglycemia in comparison to those not experiencing severe hypoglycemia Repeated episodes of hypoglycemia can lead to impairment of the counter-regulatory system with the potential for development of hypoglycemia unawareness. The short- and long-term complications of diabetes related hypoglycemia include precipitation of acute cerebrovascular disease, myocardial infarction, neurocognitive dysfunction, retinal cell death and loss of vision in addition to health-related quality of life issues pertaining to sleep, driving, employment, recreational activities involving exercise and travel. There is an urgent need to examine the clinical spectrum and burden of hypoglycemia so that adequate control measures can be implemented against this neglected life-threatening complication. Early recognition of hypoglycemia risk factors, self-monitoring of blood glucose, selection of appropriate treatment regimens with minimal or no risk of hypoglycemia and appropriate educational programs for healthcare professionals and patients with diabetes are the major ways forward to maintain good glycemic control, minimize the risk of hypoglycemia and thereby prevent long-term complications.

Parental attitudes towards overnight closed-loop glucose control in children with type 1 diabetes

BACKGROUND

This study examined parental attitudes towards overnight closed-loop (CL) glucose control in children and young people with type 1 diabetes (T1D).

METHODS

Twelve families recruited by the INsulin PUmp Therapy group (INPUT), a U.K. patient/carer-led support group for people with T1D, attended a focus meeting on CL. The concept of CL was explained, and clinical results and plans regarding the Artificial Pancreas Project at Cambridge were presented. Participants completed a questionnaire to evaluate parental feelings about T1D management and attitudes towards overnight CL insulin delivery.

RESULTS

Nineteen parents (12 mothers and seven fathers) anonymously completed the questionnaire. Main concerns about diabetes were related to long-term complications (84%) and hypoglycemia (16%). Achieving good glucose control represented major challenge for carers (83%) with nighttime being the most difficult period to manage (56%), worrying most parents (71%) particularly because of fear of hypoglycemia (33%). The development of CL to manage diabetes was welcomed by all parents (100%) with 95% happy for their child to wear a continuous glucose monitor together with an insulin pump. All parents were ready to respond to additional alarms at night with 90% parents not worried about their child's overnight insulin delivery being controlled by a computer.

CONCLUSIONS

Selected parents of children with T1D who are already insulin pump users express implied trust in the technology for overnight CL insulin delivery. Nighttime blood glucose control is the biggest challenge and concern for parents, and the development of a commercially available overnight CL system may be an important goal.

Clinical evaluation of a noninvasive alarm system for nocturnal hypoglycemia

BACKGROUND

The aim of this study was to evaluate the performance of a prototype noninvasive alarm system (HypoMon) for the detection of nocturnal hypoglycemia. A prospective cohort study evaluated an alarm system that included a sensor belt, a radio frequency transmitter for chest belt signals, and a receiver. The receiver incorporated integrated "real-time" algorithms designed to recognize hypoglycemia "signatures" in the physiological parameters monitored by the sensor belt.

METHODS

Fifty-two children and young adults with type 1 diabetes mellitus (T1DM) participated in this blinded, prospective, in-clinic, overnight study. Participants had a mean age of 16 years (standard deviation 2.1, range 12-20 years) and were asked to follow their normal meal and insulin routines for the day of the study. Participants had physiological parameters monitored overnight by a single HypoMon system. Their BG levels were also monitored overnight at regular intervals via an intravenous cannula and read on two independent Yellow Springs Instruments analyzers. Hypoglycemia was not induced by any manipulations of diabetes management, rather the subjects were monitored overnight for "natural" occurrences of hypoglycemia. Performance analyses included comparing HypoMon system alarm times with allowed time windows associated with each hypoglycemic event.

RESULTS

The primary recognition algorithm in the prototype alarm system performed at a level consistent with expectations based on prior user surveys. The HypoMon system correctly recognized 8 out of the 11 naturally occurring overnight hypoglycemic events and falsely alarmed on 13 out of the remaining 41 normal nights [sensitivity 73% (8/11), specificity 68% (28/41), positive predictive value 38%,negative predictive value 90%].

CONCLUSION

The prototype HypoMon shows potential as an adjunct method for noninvasive overnight monitoring for hypoglycemia events in young people with T1DM.

Hypoglycemia: a complication of diabetes therapy in children

The experience of hypoglycemia is probably the most feared and hated consequence of life with type 1 diabetes among pediatric patients and their parents. Although transient detrimental effects are clearly disturbing and may have severe results, there is surprisingly little evidence of long-term CNS damage, even after multiple hypoglycemic episodes, except in rare instances. Despite the latter evidence, we advocate that every treatment regimen be designed to prevent hypoglycemia without inducing unacceptable hyperglycemia and increasing the risk of micro- and macrovascular complications.