AUTONOMIC NEUROPATHY IN DIABETIC CHILDREN

Objective: Evaluate the presence of cardiovascular autonomic nerve dys function in children and adolescents with insulin-dependent diabetes m ellitus. Methodology: We studied 110 patients (54 male, 56 female) and 100 healthy sex and age-matched children. Autonomic nerve function wa s assessed by standard cardiovascular reflex tests: (1) Fall in systol ic blood pressure in response to standing. (2) Heart rate in response to standing. (3) Beat-to-beat rate variation during deep breathing. (4 ) Quotient of heart rate during and after Valsalva manoeuvre. (5) Chan ge in blood pressure response to sustained handgrip. The coefficient o f variation of heart rate was determined from 150 systoles using a mic rocomputer-based technique. The lower limits of normal were defined ac cording to statistical analysis taking into account the relationship b etween heart rate variability and age. Results: Forty-seven of the 110 diabetic children and adolescents studied showed one or more abnormal tests for cardiovascular autonomic dysfunction; many patients had an abnormality in more than one test. Twenty-two patients showed early in volvement, 18 patients had definite and 7 severe involvement. No corre lation was found between sex, glycaemic control, duration of diabetes or presence of retinopathy and persistent microalbuminuria and the aut onomic nerve function. Conclusions: In the paediatric age group also, autonomic nerve dysfunction can be present in asymptomatic diabetic pa tients. Heart rate variation during Valsalva manoeuvre and maximum/min imum 30:15 ratio are the most sensitive indices to detect autonomic ab normalities in children.