Severe Deterioration of Metabolic Control Caused by Malfunction of a Disposable Insulin Pen Device

Abstract

We communicate the case of a 68-yr-old woman diagnosed with type 2 diabetes with a severe metabolic deterioration caused by the use of a defective insulin pen device.Diabetes mellitus had been diagnosed 7 years ago and had been managed by her family physician with a combination of glymepiride and insulin glargine (48 units per day). Six weeks before presentation, the patient was switched to a twice-daily regimen of premixed aspart 70/30 (Novomix 30 Flexpen, Novo Nordisk)-36 units pre-breakfast and 18 units pre-dinner-to achieve further improvement of glycemic control. Three weeks later, she began with symptoms of hyperglycemia along with domiciliary blood glucose readings Ͼ300 mg/ dL. According to orders of her physician, the patient scaled insulin dose up to 45 units in the morning and 30 units in the evening. Nevertheless, during the previous week, she attended the hospital Emergency Unit 3 times because of malaise, dizziness, and capillary glucose levels Ͼ500 mg/dL.Formal diagnoses of diabetic ketoacidosis and hyperosmolar hyperglycemic nonketotic syndrome were ruled out by serum biochemistry and venous blood gases. The patient did not present symptoms or signs of an intercurrent infection. Leukocyte count, urinalysis, cardiac enzymes, electrocardiogram, and chest radiograph were normal. The patient was discharged after replenishment of fluids and normalization of plasma glucose with intravenous regular insulin infusion. An urgent appointment with our department was scheduled after the third discharge.The patient's weight was 83 kg and height was 162 cm. Physical stigmata of insulin resistance were lacking, and examination of insulin injection sites did not reveal lipohypertrophic areas. Simulated use of the insulin pen demonstrated that she knew proper handling of the device, and her injection technique was good, although she had been not trained to prime the pen before every injection. However, when she was required to show her currently used pen, it was obvious that it had a structural fault. The barb at the end of the piston rod was disengaged (Figure 1), so that the piston did not efficiently push to dispense insulin, even when the patient was able to fully depress the button and dose scale reset to zero after the procedure. Although the unworn pens remaining in the cartridge were in perfect condition, the patient refused to continue on the same type of insulin. She was offered a basal bolus regimen, using glargine at bedtime and insulin aspart pre-meals. Hyperglycaemia subsided in the following hours.Insulin pens devices have became the standard system for insulin delivery among diabetic patients in Europe. They are usually preferred by both patients and physicians over the traditional This article was externally peer reviewed.

Practical Aspects of Insulin Pen Devices

“…The largest of these comparative studies investigated 2280 doses of the SoloSTAR and the original FlexPen devices and showed that pens had comparable accuracy over the standard doses of 5, 10, and 30 units. 53 Another study also found that SoloSTAR and the original FlexPen were similarly accurate when used by device-naive individuals to deliver 20-unit doses of insulin. 65 One study compared the improved FlexPen with SoloSTAR: both pens showed very good accuracy, and the improved FlexPen was even more accurate than the SoloSTAR (p < 0.05) 64 ( Table 2).…”

“…Despite their ease of use, pens are mechanically more complex than syringes, and some cases of malfunction have been reported in the literature. 53,54 Therefore, patients using an insulin pen should have a backup pen available if traveling.…”

Analysis of Symposium Articles on Insulin Pen Devices and Alternative Insulin Delivery Methods

“…Additionally, pen devices and pumps are still subject to user error, as well as the possibility of mechanical malfunction, which can lead to worsened glycemic control. [9][10][11] Finally, more randomized controlled trials in a wider variety of patient populations (such as those with low health literacy, visual impairment, or dexterity problems) should be conducted to compare dosing accuracy, patient satisfaction, adherence, and efficacy of insulin pen devices versus vial/syringe.…”

Chronic Disease: Increasing Prevalence Yet Better Control

“…We also have 2 excellent associated case reports, both pertinent to diabetes: one about a malfunctioning insulin pen, 20 and one about a local trauma apparently inducing angiotension-converting enzyme inhibitor-associated edema.…”