Elsevier

Medicine

Volume 38, Issue 12, December 2010, Pages 679-685
Medicine

Pregnancy, childhood and adolescence
Type 1 diabetes mellitus in childhood

https://doi.org/10.1016/j.mpmed.2010.09.001Get rights and content

Abstract

Type 1 diabetes mellitus (T1DM) is the most common chronic metabolic condition in youth and its incidence is increasing worldwide. It must be differentiated from type 2 diabetes, which is also increasing in prevalence in parallel with the global rise in childhood obesity. T1DM presents initially with ketoacidosis (DKA) in 15–67% of cases. Glycaemic targets should be tailored to the child’s age and stage of development. With increasing age, given the proven benefit of tight metabolic control on the onset and progression of microvascular and macrovascular complications, glycaemic targets should be more stringent. Insulin regimens range from a variety of basal-bolus approaches to continuous subcutaneous insulin infusion (CSII). Self-monitoring of blood glucose (SMBG) is an essential component of management, as is attention to nutritional planning and physical activity. Care of the child and adolescent with T1DM should be multidisciplinary and involve professionals experienced in childhood diabetes, including a physician, nurse, dietitian and social worker. Maintenance of excellent glycaemic control and regular screening for complications should be emphasized, all in the context of a healthy and supportive physical and psychosocial environment.

Introduction

Type 1 diabetes mellitus (T1DM) is the most common chronic metabolic condition in children and adolescents. Diabetes mellitus (DM) comprises a group of heterogeneous conditions involving defects in insulin secretion or action, or both, resulting in hyperglycaemia and associated abnormalities in carbohydrate, protein and fat metabolism. The classification of DM is described by the American Diabetes Association.1 T1DM is by far the most common type seen in childhood. The incidence of type 2 diabetes (T2DM) is increasing most notably in the adolescent age group, in parallel with the rise in obesity throughout the world.2

Section snippets

Epidemiology

Worldwide, there are approximately 480,000 children with T1DM and 76,000 new cases are diagnosed each year.3 Incidence rates of T1DM in children and adolescents under 15 years of age vary greatly by geographical region, from the highest in Finland (57.4/100,000/year) and Canada (21.7/100,000/year) to the lowest reported in China (0.6/100,000/year) and Venezuela (0.1/100,000/year).3 The overall annual incidence is increasing at a rate of about 3%4 with the greatest increase in the youngest age

Pathophysiology

T1DM is the result of a combination of genetic and environmental influences. It most commonly results from autoimmune destruction of insulin-producing β-cells in the pancreas. Eisenbarth proposed that one or more environmental factors, such as enteroviruses, dietary factors or toxins, might trigger the development of T-cell dependent autoimmunity in genetically susceptible individuals.7 Autoimmunity is manifest by detectable antibodies to ICA512/IA-2, insulin autoantibody (IAA) and glutamic

Clinical presentation and diagnosis

The presentation of T1DM can range from a clinically stable child with symptoms of polyuria, polydipsia, enuresis, and weight loss to a severely dehydrated child with diabetic ketoacidosis (DKA). In the presence of these classical symptoms of hyperglycaemia, a single blood glucose measurement >11.1 mmol/L is sufficient to make the diagnosis of DM. In such situations, the diagnosis should not be delayed; treatment should be initiated urgently to prevent or reverse DKA. Only rarely are repeated

Diabetic ketoacidosis (DKA)

DKA results from absolute insulin insufficiency, leading to metabolic acidosis (pH <7.3 or bicarbonate <15 mmol/L), hyperglycaemia (blood glucose >11 mmol/L), ketonaemia and ketonuria.12 DKA is present at T1DM presentation in 15–67% of children, its frequency being inversely related to the incidence of T1DM in that area.13 In those with established T1DM in the United States, the incidence of DKA has been reported to be 8 episodes per 100 patient-years. Risk factors that predict DKA include

Management of T1DM in childhood

The diagnosis of T1DM is a pivotal moment for the child as well as for his/her family. T1DM is a life-long condition with serious short- and long-term implications. It is essential that from the moment of diagnosis these families receive expert care from a team of health professionals experienced in childhood diabetes, including a physician, diabetes nurse, dietitian and social worker.

At onset, children presenting without DKA can be safely managed on an ambulatory basis provided that support

Glycaemic and HbA1c targets

The Diabetes Control and Complications Trial (DCCT) demonstrated conclusively that intensive glycaemic control delays and prevents the microvascular and macrovascular complications of T1DM.16, 17 Intensification of therapy is associated with an increased risk of hypoglycaemia that can be a limiting factor in achieving good metabolic control. Severe hypoglycaemia in young children has been associated with mild cognitive deficits later in life, although the cause-and-effect relationship remains

Insulin regimens

Approaches to insulin therapeutics vary from one centre to another. Most children and teenagers now start their treatment with a combination of intermediate-acting insulin (NPH) or basal insulin analogue (insulin glargine or insulin detemir), combined with rapid-acting insulin analogues (insulin lispro or insulin aspart) given two or more times daily, with insulin doses calculated to match carbohydrate intake and ambient blood sugar. The choice of regimen should be tailored to the child’s age,

Blood glucose monitoring

Children and adolescents with T1DM are encouraged to monitor blood glucose at least four times per day (before each meal and at bedtime). Maintenance of a blood glucose logbook is essential to follow patterns and to make appropriate dose adjustments. Continuous glucose monitoring technologies have been developed and are increasingly being used in clinical care as an adjunct to intermittent monitoring.23

HbA1c is a measure of glycaemic control over the previous 4–12 weeks, weighted more heavily

Nutrition

Recommendations for nutritional intake in young people with T1DM should aim to support optimal glycaemic control, blood pressure and lipid profiles, and fit with the insulin regimen.24 If carbohydrate counting is used, insulin doses can be calculated based on the number of grams of carbohydrates consumed and on deviation from the target blood glucose. Nutritional requirements for children with T1DM do not differ from those of healthy children and adolescents.25

Physical activity

Physical activity in general leads to increased glucose utilization, although in some cases rigorous exercise may induce a stress response leading to hyperglycaemia. For children and teenagers involved in exercise activities, more frequent monitoring with either insulin dose adjustment or appropriate food intake are needed to avoid the extreme hypoglycaemia that can occur with activity. Diabetes should not limit the ability of a child to participate in sport. Methods for adjusting insulin and

Hypoglycaemia

Hypoglycaemia (blood glucose <3.9 mmol/L or 70 mg/dL) is a common unwanted effect in people treated with insulin and occurs when there is an imbalance in insulin dose, food consumed and activity. Symptoms include autonomic (adrenergic) activation and/or neurological dysfunction (neuroglycopenia).28 Recognition of symptoms of hypoglycaemia can be difficult in young children with T1DM and therefore increased monitoring of blood glucose when hypoglycaemia might be expected (overnight, after

Sick-day management

Diabetes control may deteriorate during periods of intercurrent illness. Illnesses associated with decreased oral intake may predispose to hypoglycaemia. Alternatively, the stress of some illnesses may lead to a vigorous counter-regulatory hormone response leading to hyperglycaemia and ketosis. Frequent monitoring of blood glucose and ketones, continuation of insulin therapy with appropriate dose adjustment, and timely emergency department attendance for those with repeated vomiting should help

Adolescents with T1DM

Given the association of smoking with both microvascular and macrovascular complications of DM, adolescents should be counselled in smoking prevention and cessation. It is important to address the risk of severe hypoglycaemia associated with an unpredictable daily activity schedule, intensification of the insulin regimen, and the effect of alcohol and illicit drugs on blood glucose. Adolescents who plan to or hold a driver's licence should always check their blood glucose before driving.

Transition to adult care

The transition period from paediatric to adult DM care can be a daunting time for the patient and family. In anticipation of this, adolescents with DM should be encouraged to take an increasingly active role in their diabetes care from an early stage. Teenagers should also have private time with the members of the diabetes care team as this promotes independence and responsibility. In the context of universal healthcare funding, there is an increased rate of DM-related hospitalizations in the 2

Complication surveillance

Chronic hyperglycaemia is associated with subsequent development of microvascular complications (retinopathy, neuropathy and nephropathy). Tight metabolic control delays and slows the progression of these complications. Suboptimal metabolic control has been shown to have an enduring negative effect on the development and progression of microvascular complications even if glycaemic control is subsequently ameliorated; a phenomenon termed metabolic memory.31 Other risk factors for long-term

Future developments

Pancreatic and islet-cell transplantation has been performed in adults with T1DM for end-stage renal disease or persistent metabolic instability. These procedures carry significant risks related to the procedures themselves and the need for chronic immunosuppression. Furthermore, only 10% of patients were insulin-independent at 5 years after islet-cell transplantation.18

Research to develop an effective extracorporeal artificial pancreas is ongoing. This system involves an insulin pump to

Conclusion

T1DM in young people remains a common and challenging condition. Advances continue in the understanding of the pathogenesis of DM, especially in the area of genetic susceptibility. Significant improvements have been made in the development of glucose monitors, insulin formulations and delivery systems, and the organization of health services. These substantial advances should be made known to young people and their families as reason for hope, and as an impetus to maintain the best possible

References (33)

  • S. Amed et al.

    Type 2 diabetes, medication-induced diabetes, and monogenic diabetes in Canadian children: a prospective national surveillance study

    Diabetes Care

    (2010)
  • A. Hattersley et al.

    The diagnosis and management of monogenic diabetes in children and adolescents

    Pediatr Diabetes

    (2009)
  • D.B. Dunger et al.

    ESPE/LWPES consensus statement on diabetic ketoacidosis in children and adolescents

    Arch Dis Child

    (2004)
  • C. Levy-Marchal et al.

    Geographical variation of presentation at diagnosis of type I diabetes in children: the EURODIAB study

    Diabetologia

    (2001)
  • A. Rewers et al.

    Predictors of acute complications in children with type 1 diabetes

    JAMA

    (2002)
  • C. Clar et al.

    Routine hospital admission versus out-patient or home care in children at diagnosis of type 1 diabetes mellitus

    Cochrane Database of Syst Rev

    (2007)
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