by Wesley W. Wilson, MD
NOTE: If you have any questions for “Ask the Doctor,” please send them to the Voice editorial office. The only questions Dr. Wilson can answer are the ones used in this column.
Wesley W. Wilson, MD, has retired as an Internal Medicine practitioner at the Western Montana Clinic in Missoula, Montana. Dr. Wilson was diagnosed with type 1 diabetes in 1956, during his second year of medical school. He remains interested and involved in diabetes education for patients and professionals.
Q: My question is about Glucagon. I’m a caregiver, and I have
observed that some elderly, brittle diabetics seem to not respond well to it—they
have another BAD hypoglycemic episode within 24 hours. Are there some people
who should not receive Glucagon?
A: Your question is of great interest to me. Thankfully, I’ve never received a dose of Glucagon, but I’ve always wanted it to be there, in case I needed it.
Glucagon is a valuable agent, but not without some problems. Glucagon is a “last ditch” measure to treat severe hypoglycemia. It is used only if the person is so severely hypoglycemic that they are unable to take carbohydrate by mouth. It must be injected by another person; and it only works well if there is an adequate supply of stored carbohydrate—in the form of liver glycogen.
What is Glucagon?
The liver stores carbohydrate by converting blood sugar into liver glycogen. Insulin acts to increase deposits of glycogen into the liver and there lies the problem with insulin—it can divert glucose into liver glycogen, even if blood sugar levels are too low. Glucagon works in reverse, stimulating the release of stored carbohydrate (liver glycogen), thereby increasing the blood sugar level.
The Importance of Frequent Testing
Frequent blood sugar testing can provide some protection against unsuspected low blood sugar. Perhaps even more important is learning how to predict activity or food intake that makes low sugars more likely.
Hypoglycemia is best treated by prevention, not by rescue efforts. Many persons with type 1 diabetes lose the ability to sense hypoglycemia. This is called hypoglycemic unawareness. The person with hypoglycemic unawareness has little or no perception of early low blood sugar. Their first event with hypoglycemia may be confusion, or loss of consciousness.
The Brittle Diabetic
“Brittle Diabetes” is a term used to describe wildly fluctuating sugars. Many persons with “brittle” diabetes are slender, even malnourished, and often have some diabetic complications. A slender or malnourished person is at greater risk for hypoglycemia, since they lack the cushion of adequate carbohydrate stores (glycogen) in the liver.
Their blood sugar control is often not ideal. However, the brittleness may
improve with careful education regarding management of the diabetes.
The Yo-Yo Effect
A frequent pattern is: inadequate insulin to cover a meal, resulting in high blood sugar—then too large a correction of insulin, which causes the sugar to fall too low, followed by an excess consumption of carbs, which again results in too-high blood sugar. This yo-yoing of the blood sugar makes hypoglycemia far too frequent.
How Glucagon Works
Your question is important since with a rescue agent like Glucagon we want it always to work but to have no tendency to cause repeated low sugars. Some persons do show increased risk for recurrent low sugars after using Glucagon—why? Glucagon is a hormone, produced, like insulin, in cells called the Islets of Langerhans, located in the pancreas. Alpha cells produce Glucagon, beta cells produce insulin.
These two hormones are like yin and yang—insulin lowers blood sugar by helping the body use glucose, and by shifting blood sugar from the blood into liver in the form of glycogen. Glucagon acts to break down liver glycogen to increase blood sugar. However, there must be enough liver glycogen for a Glucagon injection to raise blood sugar. Persons with type 1 diabetes and those who are malnourished have less liver glycogen available, and frequent hypoglycemia also depletes liver glycogen stores.
A Final Precaution
The package insert in Glucagon emphasizes the importance of pushing a carbohydrate
diet to replace glycogen stores after use of Glucagon.
Wes Wilson