Hypoglycemia is a fact of life for people with type 1 diabetes and for many people with type 2. Attitudes about hypoglycemia (low blood glucose) range from paralyzing fear that prevents effective management to indifference and denial that lead to unnecessary risk.
Severe hypoglycemia, defined as requiring the assistance of another person, can lead to confusion, loss of consciousness, seizures, and serious injury. In rare cases, hypoglycemia itself can be fatal. It's estimated that, on average, a person with type 1 diabetes has one episode of severe hypoglycemia per year. Just in the past few months, I've heard about two serious car crashes involving hypoglycemic drivers and two deaths in which hypoglycemia was a possible cause.
Hypoglycemia unawareness (HU) puts people with diabetes at especially high risk for severe hypoglycemia. People with HU are unable to feel the early warning signs of hypoglycemia, like the typical shakiness and sweating, which would otherwise cause them to treat the low blood glucose before it became dangerously low. Instead, they have no symptoms even when their blood glucose dips down into the 40s and 50s, and their first sign of hypoglycemia may be confusion or "acting goofy," which is a result of hypoglycemia, not a warning sign. Recurrent hypoglycemia produces HU because the brain gradually adapts to the low blood glucose and, over time, no longer produces the warning symptoms. Symptoms will often return after a period of strict avoidance of hypoglycemia, but some people with long-standing diabetes develop irreversible HU.
If you've had severe hypoglycemia, are having frequent hypoglycemia, or think you may have hypoglycemia unawareness, please make your diabetes care provider aware of it as soon as possible. Frequent low blood glucose of any severity greatly increases the risk of having an episode of severe hypoglycemia in the near future. The good news is that hypoglycemia risk can almost always be reduced by changing glucose targets, adjusting medications, or better matching insulin doses to physical activity and carbohydrate consumption. A continuous glucose monitor can also guard against hypoglycemia.
People who take insulin or oral medications that can cause hypoglycemia must keep within reach at all times a source of glucose such as glucose tablets or gel, and must always know what their glucose is before driving. A glucagon emergency kit should be kept on hand for anyone with a history of frequent or severe hypoglycemia, and probably for anyone with type 1 diabetes. A medical alert bracelet or necklace can be a lifesaver when someone experiencing hypoglycemia is unable to communicate.
Efforts to achieve good glucose control must go beyond simply aiming for an A1C target. They must include a healthy respect for the risk of serious hypoglycemia. Patients and diabetes care professionals need to apply vigilance, clinical judgment, and common sense to prevent hypoglycemia from becoming a greater risk than diabetes itself.