Cardiac Autonomic Dysfunction in Children and Adolescents with Type 1 Diabetes Mellitus

Introduction: Autonomic neuropathy is less well documented in children with type 1 diabetes mellitus and has received less attention than other diabetic complications. Sudden death and cardio-respiratory arrest in patients with type 1 and type 2 diabetes mellitus have been attributed to cardiac autonomic dysfunction. Aim: The aim of this study was to determine the prevalence of autonomic neuropathy in a cohort of children and adolescents with type I diabetes and to examine the relationship between this complication, and duration of diabetes and degree of glycemic control. Material and Methods: Seventy-six type 1 diabetic children and adolescents below age 18 years of age, and 76 nondiabetic school children, matched for age and sex, had their cardiac autonomic nerve function assessed using four autonomic function tests. Namely the respiratory sinus arrhythmia test ; the Valsalva ratio test; the heart rate response to standing, and the blood pressure response to standing. The first three are tests of parasympathetic function, while the last one is a sympathetic function test. Results: The diabetic patients had a median age of 12 years and their median duration of diabetes mellitus was 43 months. They showed a significantly higher resting heart rate and a significant drop in systolic and diastolic blood pressures upon standing compared to the control group. The duration of diabetes mellitus showed linear correlation to the symptoms of autonomic dysfunction. Conclusion: We conclude that cardiac autonomic neuropathy is not rare in young diabetic patients of relatively short duration of illness where glycemic control is less than optimal. Such tests may serve as long-term prognostic indicators in diabetic patients.Keywords:autonomic neuropathy, peripheral neuropathy, glycemic control, Middle East Sudan Journal of Medical Sciences Vol. 2 (2) 2007: pp. 95-10