MKSAP quiz: Hypoglycemia from insulin error
This month's quiz asks readers to evaluate a 22-year-old woman with a recent type 1 diabetes diagnosis who has called about anxiety, shakiness, and sweating. She reports accidentally taking 18 units of insulin aspart before bedtime, rather than the prescribed basal insulin, insulin glargine.
A 22-year-old woman is evaluated during a telephone call for anxiety, shakiness, and sweating. She reports accidentally taking 18 units of insulin aspart before bedtime, rather than the prescribed basal insulin, insulin glargine. Type 1 diabetes mellitus was diagnosed 2 weeks earlier. Her last meal was 4 hours ago, at which time she took her normal prescribed mealtime dose of insulin aspart. Medical history is otherwise unremarkable. Medications are insulin glargine, 18 units at bedtime, and insulin aspart, 6 units three times daily with meals.
She reports that her initial fingerstick blood glucose level is 56 mg/dL (3.1 mmol/L). A repeat fingerstick blood glucose level 5 minutes into the telephone call is 54 mg/dL (3.0 mmol/L).
The patient is alert throughout the telephone call.
Which of the following is the most appropriate advice?
A. Administer glucagon injection intramuscularly and repeat fingerstick blood glucose
measurement in 15 minutes
B. Consume 15 g of carbohydrates and repeat fingerstick blood glucose measurement
in 15 minutes
C. Monitor symptoms and repeat fingerstick blood glucose measurement in 15 minutes
D. Proceed to the emergency department for evaluation
MKSAP Answer and Critique
The correct answer is B. Consume 15 g of carbohydrates and repeat fingerstick blood glucose measurement in 15 minutes. This item is available to MKSAP subscribers as item 9 in Extension Set 4 of the Endocrinology and Metabolism section. More information about MKSAP is online.
The patient should be advised to consume 15 g of carbohydrates and recheck her fingerstick blood glucose level in 15 minutes (Option B). Hypoglycemia is defined as a glucose level below 70 mg/dL (3.9 mmol/L). The development of hyperadrenergic symptoms, such as sweating, anxiety, and tremors, is a normal physiologic response to hypoglycemia. With severe hypoglycemia, typically seen with a plasma glucose level below 54 mg/dL (3.0 mmol/L), neuroglycopenic signs or symptoms may occur, such as altered mental status, dysarthria, and confusion, which may lead to obtundation, seizure, or death if not treated. Inappropriate insulin administration is a frequent cause of hypoglycemia in patients with diabetes mellitus, as seen in this patient who took rapid-acting insulin meant for pre-meal use in place of her scheduled basal insulin. Initial hypoglycemia treatment in persons who are alert includes consuming 15 g of a rapidly digested carbohydrate (or a 15-g glucose tablet), followed by repeating the blood glucose measurement in 15 minutes, with a goal of raising the blood glucose level above 70 mg/dL (3.9 mmol/L). This is commonly known as the “Rule of 15.” If blood glucose does not rise above 70 mg/dL (3.9 mmol/L) after treatment, repeat treatment with 15 g of carbohydrates should be given.
Glucagon is a counterregulatory hormone to insulin that raises blood glucose levels primarily through increased hepatic gluconeogenesis. It is indicated for treating severe hypoglycemia when the patient is unable to safely consume carbohydrates. It may be administered by the patient or by others nearby. Patients who are unable to consume oral carbohydrates and require glucagon should proceed to the emergency department for evaluation and monitoring, as they are at high risk for refractory hypoglycemia. This patient is alert and capable of consuming carbohydrates; she does not currently require glucagon or an emergency department referral (Options A, D).
Rechecking the blood glucose level without intervention is inappropriate and dangerous, as untreated hypoglycemia may quickly lead to severe manifestations, such as neuroglycopenia, seizure, or death (Option C).
Key Point
- Initial treatment of hypoglycemia in an alert patient requires oral consumption of carbohydrates with a goal of increasing the blood glucose level to greater than 70 mg/dL (3.9 mmol/L).