Research Helps to Explain Hypoglycemic Unawareness

By: Diana Barnes-Brown for Diabetes1

The most common advice for newly diagnosed diabetics is to develop a consistent diet, exercise program, and insulin regimen; check in with their diabetes specialist regularly; and to learn the signs of the most common complications so that they can manage them in early stages with home care. But for some people with diabetes, simply following their insulin and treatment regimens and memorizing the symptoms to watch out for may not be enough.

This is because of a phenomenon called hypoglycemic unawareness, which is the inability of diabetics to notice the symptoms of hypoglycemia when they are experiencing them.

Hypoglycemia is the medical term for low blood sugar, which can occur in diabetics when their insulin regimen does not match their food intake, or when their body undergoes certain chemical changes due to lack of exercise, drinking alcohol, or other factors. Dangerous complications result if hypoglycemia is not reversed. These include diabetic coma, brain damage, and even death.

In most people, and most diabetics, the brain is able to recognize signs of hypoglycemia and respond to raise blood sugar to normal levels. But in some diabetics, this process does not work as well as it should, and may leave them without the information they need to prevent further episodes.

But recently, researchers at the Juvenile Diabetes Research Fund Yale Center for the Study of Hypoglycemia have found clues as to what causes the warning signs of hypoglycemia to become muted.

Rory McCrimmon, MD and fellow researchers at Yale found that when the urocortin I protein, which occurs naturally in the brain, is produced in abnormally high quantities, it may lead to inability to perceive hypoglycemia.

The study, published in the Journal of Clinical Investigation, demonstrated that a key glucose-sensing region in the brains of rats loses sensitivity after being exposed to urocortin I, and that this loss of sensitivity continues for at least 24 hours. If this same phenomenon were active in humans (it likely is, since these pathways are largely similar in rats and humans), it would explain why sensing repeated hypoglycemic episodes could be difficult for diabetics.

“Recurrent episodes of hypoglycemia impair [responses] to a subsequent episode of hypoglycemia,” wrote the researchers. “For individuals with type 1 diabetes, this markedly increases (by 25-fold) the risk of severe hypoglycemia and is a major limitation to optimal insulin therapy.”

The team noted that this discovery would be a helpful key to treatment of hypoglycemic unawareness and prevention of hypoglycemia and serious related complications.  If medical researchers are able to develop drug therapies that prevent the muting of urocortin I protein response, these may be instrumental in treating hypoglycemic unawareness.

In a complimentary article also published in the Journal of Clinical Investigation, Philip Cryer of the Washington University School of Medicine named hypoglycemia from insulin treatment as a “limiting factor” in the control of blood sugar. He noted that the availability of the artificial pancreas (already in development stages) in coming years would likely help to address this challenge, until treatments which replace the insulin-secreting cells damaged in diabetics become widely available.

Symptoms of Hypoglycemia

The following are the main symptoms of hypoglycemia. It is important to remember that these symptoms may NOT show themselves in diabetics if a prior episode of hypoglycemia has occurred recently. For this reason, preventive action such as blood sugar monitoring and consistent meals, insulin, and exercise patterns is a good idea.

·        Hunger

·        Nervousness and shakiness

·        Perspiration, including night sweats

·        Dizziness or light-headedness

·        Sleepiness

·        Confusion

·        Difficulty speaking

• Anxiety
• Weakness