Type 1 diabetes can be difficult to control in young children because of variations in food intake and exercise, the difficulty of administrating low doses of insulin, and frequent viral infections. These young children also have increased sensitivity to short-acting insulin and often cannot tell their caregivers when they are having symptoms of hypoglycemia. Pump therapy may be a more effective and safer way to administer insulin therapy in these children. Litton and associates studied the use of pump therapy in nine children younger than four years who had type 1 diabetes and severe hyperglycemia.
Family members received thorough education about hyperglycemia and hypoglycemia and were provided with easy access to staff members for questions or concerns. Dietary information was provided to all, and bedtime snacks were recommended. Initial therapy for all children included multiple doses of insulin during the day using long- and short-acting preparations. Blood glucose measurements were obtained four to 10 times daily along with urine testing for ketones daily and when illness or hyperglycemia occurred. Pump therapy was recommended for use in children who, after at least six months of injection treatment, developed recurrent hypoglycemia, persistent glycosylated hemoglobin (HbA1c) elevation, erratic variations in blood sugar levels, or recurrent ketoacidosis or severe hyperglycemia. Constant adult supervision is required for any child using pump therapy. Caregivers of children starting pump therapy were educated about its use and had to be willing to monitor blood glucose levels at least four times daily. Children had to be able to tolerate and avoid touching the catheter and the pump mechanism.
Insulin pump therapy was initiated with a steady dosing of Humalog augmented by bolus injections at the beginning or end of meals. Basal and bolus injection rates were reviewed daily with a nurse educator to achieve preprandial blood glucose levels of 80 to 180 mg per dL (4.4 to 10 mmol per L) and postprandial glucose levels of less than 200 mg per dL (11.1 mmol per L). HbA1c levels were measured every three months. Episodes of hypoglycemia were identified by appropriate symptoms reported by caregivers.
Among the nine children studied, HbA1c levels during the six months before pump initiation averaged 9.5 percent. During pump therapy, this level decreased in all nine children to a mean level of 7.9 percent. The frequency of hypoglycemic episodes also decreased from a prepump mean of 0.52 per month to 0.09 episodes per month after initiation of pump therapy. There were no infections caused by catheter placement and no pump failure episodes.
The authors conclude that continuous infusion of insulin by pump therapy more closely matches need variations reflected by caloric intake and energy expenditure. Strong care-giver motivation is necessary to monitor pump function and blood glucose levels. Assuming that tight glucose control in young children decreases vascular complications of diabetes, a fact that has not yet been proved, intensive diabetes control in this young age group is probably desirable. There is some evidence that hyperglycemia in this age group may cause microalbuminuria, early retinopathy, and later impaired intellectual function. Enhanced glucose control and an actual decrease in the number of episodes of hypoglycemia can be achieved when motivated families treat a young child with diabetes using pump therapy under careful supervision.
editor's note: A review of studies of intensified insulin treatment in adult patients with type 1 diabetes mellitus, whether using daily multiple injections or insulin pump therapy, demonstrated increased risk for hypoglycemia and ketoacidosis (Egger M, et al. Risk of adverse effects of intensified treatment in insulin-dependent diabetes mellitus: a meta-analysis. Diabet Med November 1997;14:919–28). The inclusion of an insulin pump, as sole therapy or in combination with multiple daily injections, accounted for the increased risk of ketoacidosis. Mortality risk did not change with intensive therapy. So, although the benefits of intensified treatment appear clear, the risks, especially when use of an insulin pump is included in management, are increased. Patients using insulin pumps (or their caretakers) require significant education, particularly when short-acting forms of insulin are used, because infusion disruption will more rapidly result in insulin deficiency. Glycemic targets must be established that consider the patient's level of involvement and ability to closely monitor serum glucose levels.—r.s.