Objective: To demonstrate the benefits and to advocate the safety and efficacy of using an insulin pump with U-500 insulin in comparison with U-100 insulin for a pregnant patient with diabetes requiring massive doses of insulin.
Methods: We present a detailed case report about the use of continuous subcutaneous insulin infusion with U-500 insulin during pregnancy. Dose calculation is reviewed, and the benefits of insulin pump therapy in patients with diabetes are discussed.
Results: A 34-year-old white woman, with a history of type 2 diabetes for 7 years, was seen at 17 weeks of gestation because of episodes of hyperglycemia and hypoglycemia accompanied by a very high insulin requirement. At the time of initial assessment, the patient was hospitalized with diabetic ketoacidosis and was being treated with 400 U/day of intravenously administered insulin. She responded well to intravenous therapy, but when switched to a regimen of NPH and regular insulin, she continued to have high blood glucose levels (despite 4 to 5 insulin injections a day, with a total daily dose up to 400 to 450 U). Use of an insulin pump was instituted, which presented another challenge because of the limited reservoir capacity and the need to change sites at least once or twice a day. We decided to initiate U-500 insulin therapy with a total basal rate of 40 U/day. Her meal carbohydrate insulin ratio and correction bolus were calculated on a U-100 scale. Then each estimated dose for meal coverage, depending on her carbohydrate intake, as well as the appropriate corrections were totaled and divided by 5 to convert to U-500. Throughout the rest of her pregnancy, the patient was able to maintain tight glycemic control, with no further hospitalizations for stabilization of hyperglycemia or hypoglycemia.
Conclusion: To our knowledge, this is the first report of successful management of difficult to control diabetes by means of an insulin pump with use of U-500 insulin in a pregnant patient who required massive doses of insulin.