Updated June 09, 2006

Hypoglycemia Unawareness

A condition in which a person with diabetes does not experience the usual early warning symptoms of hypoglycemia (low blood sugar).

Ordinarily, when a person's blood sugar level drops, the body tries to raise it by releasing the hormones glucagon and epinephrine. Glucagon spurs the liver to release stored glucose. Epinephrine (or adrenaline) signals the liver to produce more glucose. It also causes the typical early warning signs of hypoglycemia, which include sweating, trembling, butterflies in the stomach, tingling, numbness, and rapid pulse.

People with hypoglycemia unawareness don't experience these symptoms. Instead, without warning, they lapse into severe hypoglycemia, becoming confused or disoriented or falling unconscious. These individuals have lost the epinephrine response to low blood sugar, along with the symptoms epinephrine normally brings on.

There are several possible causes of hypoglycemia unawareness. It can be caused by nerve damage that affects the body's ability to secrete epinephrine. People with Type 1 diabetes sometimes develop impaired epinephrine secretion. It can also be the result of very tight blood sugar control, which can dull the body's ability to feel a drop in blood sugar level. Sometimes, maintaining slightly higher blood sugar levels for a period of time can improve the ability to detect low blood sugar.

Hypoglycemia unawareness can be dangerous to both the person experiencing it and those around him. Because he doesn't realize that his blood sugar is low, someone with this condition may not know that he is not thinking clearly or that he shouldn't drive. If his hypoglycemia goes untreated, he can lose consciousness, and his blood glucose level will continue to fall.

If you have experienced hypoglycemia without warning, be sure to discuss it with your health-care team. They can help you reverse the situation.

This article was written by Robert S. Dinsmoor, a Contributing Editor of Diabetes Self-Management.

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