Endocrine Abstracts

Introduction: The management of type 1 diabetes (T1D) in young children can be extremely challenging due to high insulin sensitivity, unpredictable eating and activity and difficulty recognizing symptoms of hypoglycaemia. Continuous subcutaneous insulin infusion (CSII) therapy is beneficial in managing young children, however the small insulin doses required challenge the accuracy of standard concentration (100 IU/ml) CSII.

Case report and literature review: A 15-month-old, previously healthy boy was admitted with the diagnosis of diabetic ketoacidosis in new T1D after presenting with a 7-day history of polyuria, polydipsia, lethargy, vomiting and increased work of breathing. Due to oscillating consciousness and refractory tachycardia he was transferred to a paediatric intensive care unit where he was treated for severe shock and cerebral oedema. During his admission he developed increasing abdominal distension and he was diagnosed with extensive bowel necrosis. Subtotal colectomy was performed and total parenteral nutrition started. Twenty-seven days into his admission sensor-augmented CSII was started and based on his low insulin requirements the following calculations were made: 3.5 IU/day at 0.025 IU per mini-bolus (lowest rate) =1 bolus every 10 minutes. We believed this would be insufficient to achieve good glycaemic control and we turned to the literature for support. A study by Borot (J Diabetes Sci Technol. 2014) reports increased rates of flow errors and significant occlusion detection delays with low infusion rates. A study by Elleri (BMJ Open Diabetes Res Care 2014) showed a tendency towards reduced hypoglycemia and reduced glucose variability using diluted insulin. Finally, the study by Ruan (Diabetologia 2015) concluded that diluting insulin does not change its pharmacokinetics and may result in less variable absorption. The decision was made to start our patient on diluted insulin 10 IU/ml using diluting medium for insulin aspart (Novo Nordisk A/S). Good glycaemic control (HbA1c 47 mmol/mol) was achieved despite multiple challenges in his slow transition from parenteral to enteral nutrition.

Conclusion: Very young children with low insulin requirements challenge the accuracy of standard concentration CSII which may be overcome by diluting insulin. This report adds our experience to the limited evidence on using diluted insulin.