Hypoglycaemia in childhood diabetes. I. Clinical signs and hormonal counterregulation

Glucagon in artificial pancreas systems: Potential benefits and safety profile of future chronic use

The role of glucagon in the pathophysiology of diabetes has long been recognized, although its approved clinical use has so far been limited to the emergency treatment of severe hypoglycaemia. A novel use of glucagon as intermittent mini-boluses is proposed in the dual-hormone version (insulin and glucagon) of the external artificial pancreas. Short-term studies suggest that the incorporation of glucagon into artificial pancreas systems has the potential to further decrease hypoglycaemic risk and improve overall glucose control; however, the potential long-term safety and benefits also need to be investigated given the recognized systemic effects of glucagon. In the present report, we review the available animal and human data on the physiological functions of glucagon, as well as its pharmacological use, according to dosing and duration (acute and chronic). Along with its main role in hepatic glucose metabolism, glucagon affects the cardiovascular, renal, pulmonary and gastrointestinal systems. It has a potential role in weight reduction through its central satiety function and its role in increasing energy expenditure. Most of the pharmacological studies investigating the effects of glucagon have used doses exceeding 1 mg, in contrast to the mini-boluses used in the artificial pancreas. The available data are reassuring but comprehensive human studies using small but chronic glucagon doses that are close to the physiological ranges are lacking. We propose a list of variables that could be monitored during long-term trials of the artificial pancreas. Such trials should address the questions about the risk-benefit ratio of chronic glucagon use.

Minimizing morbidity of hypoglycemia in diabetes: a review of mini-dose glucagon

Type 1 diabetes is a common chronic disease of childhood and one of the most difficult conditions to manage. Advances in insulin formulations and insulin delivery devices have markedly improved the ability to achieve normal glucose homeostasis. However, hypoglycemia remains the primary limiting factor in achieving normoglycemia and is a frequent complication in children with acute gastroenteritis and/or poor oral intake. In situations of impaired carbohydrate intake or absorption, glucagon therapy is the only out-of-hospital treatment option available to families and caregivers. Glucagon is recommended for the treatment of severe hypoglycemia and rapidly increases blood glucose by increasing hepatic glucose production from glycogenolysis. Mini-dose glucagon is a widely utilized off-label treatment for managing mild or impending hypoglycemia and is administered as a small subcutaneous injection. It was initially described for use in children who were unable to tolerate or absorb oral carbohydrates but not in need of advanced medical care. Yet, mini-dose glucagon may be useful in any individual with relative insulin excess. The regimen aims to prevent severe hypoglycemic episodes and is safe, effective, and easily administered by patients and caregivers in the out-of-hospital setting. By empowering patients and their families, this important tool could help to alleviate the physical, psychosocial, and financial burden evolving from impending hypoglycemia.

Pubertal stage and hypoglycaemia counterregulation in type 1 diabetes

AIMS

To compare physiological and autonomic responses to acute hypoglycaemia in diabetic children in pre-, mid-, and post-pubertal stages of development.

METHODS

Twenty seven children (8 pre-pubertal, 7 mid-pubertal, 12 post-pubertal) with type 1 diabetes were studied. Hypoglycaemia was induced by insulin infusion until an autonomic reaction (R) was identified. Counterregulatory hormone levels were measured at baseline, R, R+15, and R+30 minutes. Haemodynamic changes and sweat production were measured.

RESULTS

The mean blood glucose level at R was lower in pre-pubertal than mid-pubertal children (2.0 v 2.5 mmol/l), and was positively correlated with HbA1c. Glucagon and noradrenaline responses to hypoglycaemia were minimal in all children. A brisk increase in pancreatic polypeptide (PP) concentration only occurred in post-pubertal children. Only two children showed a sweating response to hypoglycaemia.

CONCLUSIONS

The blood glucose level at which sympatho-adrenal responses to hypoglycaemia were activated was associated with glycaemic control, and varied with pubertal stage. As in adults, the glucagon response to hypoglycaemia was deficient within a few years of developing diabetes. However, sweating and secretion of PP in response to hypoglycaemia did not occur until after puberty, indicating some qualitative differences from adults.

Impaired counterregulatory hormone responses to hypoglycemia in children and adolescents with new onset IDDM

Children with long-standing IDDM have impaired counterregulatory responses to hypoglycemia. To determine whether children with new onset IDDM also have altered counterregulation, we studied the counterregulatory responses to hypoglycemia in twenty children with new onset IDDM (5-6 days, age 12.6 +/- 2.9 yr, mean +/- SD), and compared these responses to 47 subjects with long-standing IDDM (duration 7.8 +/- 3.6 yr, age 15.3 +/- 2.5 yr) and 21 controls (age 14.2 +/- 2.8 yr). Six new onset subjects were restudied three months later during their remission. Glucose nadir in new onset (2.7 +/- 0.1 mmol.l-1) was similar to controls (2.4 +/- 0.1 mmol.l-1), but was higher than in long-standing IDDM (2.2 +/- 0.1 mmol.l-1). Both groups of diabetic subjects had lower glucagon responses to hypoglycemia than controls (p < 0.005). Glucagon responses in new and long-standing diabetes did not differ. Epinephrine was diminished in new IDDM compared to controls (p < 0.01). Glucose recovery was faster in new onset than in long-standing IDDM (p < 0.001) and the same as in controls. Responses remained diminished 3 months after diagnosis despite increased C-peptide and lower glycosylated hemoglobin. Thus, children with IDDM have diminished counterregulatory responses to hypoglycemia at diagnosis, that are similar to those in long-standing IDDM. The reasons for this impairment and its clinical application in childhood require further investigation.

Medium-chain acyl-coenzyme A dehydrogenase deficiency: clinical course in 120 affected children

Medium-chain acyl-coenzyme A dehydrogenase deficiency is an autosomal recessive disorder of beta-oxidation of fatty acids manifested by episodic hypoglycemia, encephalopathy, apnea, and sudden death. Medical data were obtained on 120 patients with medium-chain acyl-coenzyme A dehydrogenase deficiency referred to Duke University Medical Center for biochemical testing. There were 55 male and 65 female subjects ranging from birth to 19 years of age; 118 subjects were white. Twenty-three children (19%) died before the diagnosis was made. Follow-up data were available in the 97 surviving patients for an average of 2.6 years after diagnosis. Psychodevelopmental data were collected on 73 patients older than 2 years of age. Unexpected morbidity included developmental and behavioral disability, chronic muscle weakness, failure to thrive, and cerebral palsy. We conclude that unidentified patients with this disorder have a significant risk of sudden death in early childhood and that survivors have a significant risk of developmental disability and chronic somatic illness.

Hypoglycaemia in the diabetic child

Hypoglycaemia is the most frequent acute complication of insulin-dependent diabetes mellitus. The clinical symptoms of insulin-induced hypoglycaemia can be grouped into those attributable to the sympathetic and adrenergic responses, e.g. tremor, pallor, palpitation, sweating, mydriasis ('hypoglycaemia awareness'), and those attributable to brain dysfunction, ranging from headache to convulsions and coma. Hypoglycaemia in diabetic children can occur at any time of the day, but nocturnal hypoglycaemia is a particular fear and worry. The frequency of mild hypoglycaemia is almost impossible to ascertain and the incidence of severe hypoglycaemia varies between 0.07 and 3.6 episodes per patient-year, though most authors report a range of 0.1-0.2 episode per patient-year. The most frequent causes of hypoglycaemia in diabetic children are deviations from treatment routine such as strenuous exercise, omission of snacks or skipped meals, and gross deviations from the prescribed times of insulin injections and recommended doses of insulin. Other predisposing factors include intensified insulin treatment, improved glycaemic control, young age, longer duration of diabetes and defective counterregulation. The available paediatric studies do not seem to support the suggestion that human insulin impairs the perception of hypoglycaemic symptoms ('hypoglycaemia unawareness') and increases the frequency of hypoglycaemic episodes, but further conclusive studies are needed. Prolonged and recurrent severe hypoglycaemia, particularly in younger children, can cause permanent neuropsychological dysfunction (e.g. learning disabilities) and permanent electroencephalographic abnormalities. Mild hypoglycaemia has also been documented to affect cognitive function, and the performance of neuropsychological tasks can remain decreased for some time (up to several hours) after full clinical recovery from hypoglycaemia. An impending hypoglycaemic attack can usually be averted by the ingestion of 20 g of rapidly absorbed carbohydrate. A severe episode can be effectively treated outside hospital with subcutaneous or intramuscular glucagon (0.5-1.0 mg) or in the hospital by an intravenous bolus of 0.2-0.5 g/kg glucose followed by a continuous glucose infusion. Patient and parent education and vigilant application of diabetes self-care principles are perhaps the most effective means of prevention, but in very young children a less strict metabolic control (higher glycosylated haemoglobin levels) may be necessary.

Symptomatic hypoglycaemia in childhood diabetes: a population-based questionnaire study

The occurrence of severe and mild hypoglycaemic attacks and their symptoms and signs were studied in 92 insulin-dependent diabetic children, 7-18 years old. A questionnaire was distributed to all families and they were interviewed by an experienced nurse. Severe attacks, for which the help of an adult was needed, were reported by 44% of the children during a 12-month period. Thirty-seven per cent of the attacks occurred in the mornings, most often attributed to extra physical exercise, but equally often without any obvious cause. They were more common in children with strict blood glucose control measured as HbA1c. Fast-acting carbohydrates, given by parents, relieved the attack in most children, but 15% needed a glucagon injection and 12% intravenous glucose. In all, 16% were admitted to hospital. Mild events occurred in 97% of the children, at least once per week in 53% of the children, and were not related to blood glucose control. They were often attributed to extra physical exercise and occurred mainly between breakfast and lunch. Initial symptoms were tremor and hunger; during the whole event tremor and sweating were most common. Parents noted pallor as the most common sign. The frequency of severe or mild attacks could not be correlated to the age of the child, duration of diabetes, daily dose or number of insulin injections.

Hypoglycaemia in childhood diabetes. II. Effect of subcutaneous or intramuscular injection of different doses of glucagon

Hypoglycaemia (blood glucose 1.3-2.5 mmol/l) was induced in thirty diabetic children by reduction of their morning meal. Glucagon, 10 or 20 micrograms/kg was then given by intramuscular or subcutaneous injection. Ten min later, all signs of hypoglycaemia had disappeared and blood glucose concentrations increased by 0.7-3.3 mmol/l. Glucagon plasma concentrations at glucose nadir were low, 23 +/- 8 pmol/l, rose to 300 +/- 42 ten min after the injection and reached peak values after another ten min. Later, a slow decrease was noted. No significant difference of blood glucose or plasma glucagon concentrations were found after subcutaneous or intramuscular injections of 20 micrograms/kg. After 10 micrograms/kg, slightly lower increase of blood glucose was seen, but the clinical effect was equally good. Nausea occurred in four children given 20 micrograms/kg. The rise of blood glucose did not correlate to the peak glucagon concentration obtained after the injection but showed significant correlations to the lowest glucose concentration and, inversely, to the concentration of free insulin in blood at glucose nadir. It is concluded that glucagon injections are effective in hypoglycaemia in insulin-treated diabetic children and that the injection of 10-20 micrograms/kg gives long-standing supraphysiological concentrations which make repeated injections unnecessary.