Diabetes 911. Larry A. Fox

Chapter 2 Hypoglycemia

      Hypoglycemia (low blood glucose) is probably the most common emergency in children and adults with diabetes. With the use of more intense insulin regimens, improved blood glucose control comes at the risk of more frequent hypoglycemia. Whether mild, moderate, or severe, hypoglycemia can leave a lasting impression on someone with diabetes or his or her caretaker (especially a parent). In severe cases, hypoglycemia can sometimes have devastating consequences, such as death related to hypoglycemia while driving. Therefore, people with diabetes, and others who spend a lot of time with them (parents, other relatives, school personnel, teachers, co-workers, friends, etc.), need to know how to properly handle this emergency.

      This chapter covers recognition and treatment of hypoglycemia. It focuses not only on mild and moderate low blood glucose levels, but also proper treatment of severe events. One of the keys to success with nearly everything is planning ahead—hypoglycemia is no exception. Thus, this chapter also addresses the prevention of hypoglycemia, including when playing sports or exercising. Lastly, this chapter reviews how medications and alcohol influence the development and recognition of hypoglycemia.

       SYMPTOMS OF HYPOGLYCEMIA

      Hypoglycemia is generally classified as mild, moderate, or severe. This is based on the symptoms of low blood glucose levels (how you feel when your sugar is low). The classification is not based on actual blood glucose numbers. The symptoms of hypoglycemia can vary significantly from person to person and do not entirely depend on the blood glucose level. For example, there can be no symptoms at all, even with a very low blood glucose level (under 40 mg/dl). Or a person can have moderate or severe symptoms with a slightly low blood glucose or a level that is not even low (more than 70 mg/dl).

      Many of the symptoms of low blood glucose levels (see SIGNS OF MILD OR MODERATE HYPOGLYCEMIA) are manifestations of the body’s response to the low sugar level. Low blood glucose levels activate the sympathetic nervous system, causing early warning signs of hypoglycemia, many of which people recognize. Such symptoms indicate that the body is trying to raise its blood glucose level. These early symptoms are also what you feel when blood glucose drops rapidly but may not be considered low. It is not just the blood glucose level that determines whether someone has symptoms or not—it is also dependent on how fast the blood glucose level is falling.

      Other symptoms, however, indicate that the brain is not getting enough of the glucose it needs to function properly. These are the late signs of hypoglycemia and occur if early symptoms are not sensed or recognized or are ignored. The symptoms of mild or moderate hypoglycemia can vary from person to person. Even one person may have different symptoms one day compared with another, depending on surrounding circumstances.

      A severe low blood glucose level is much worse and indicates that the brain is severely deprived of the glucose it needs to function properly. Hypoglycemia is always considered severe if it is accompanied by unconsciousness or a seizure (convulsion). It is also severe if you are still conscious but unable to correct the hypoglycemia yourself, whether it is because you cannot recognize it or because you need the help of another person. In infants, toddlers, and young children, this definition does not always apply because they always require someone else’s help to treat hypoglycemia, regardless of severity, just by virtue of their young age. It is important to treat severe hypoglycemia immediately to prevent brain damage, but even more important to prevent it altogether.

      WHEN DOES HYPOGLYCEMIA OCCUR?

      Hypoglycemia occurs when the balance between your insulin levels and the amount of available glucose is disrupted. If your body does not have enough food or is unable to make enough glucose (causing an insufficient amount of glucose available for your body to use for energy), blood glucose levels will decrease. Low blood glucose levels may occur if:

      

you skip meals or snacks or eat them much later than usual (if a fixed insulin regimen is used)

      

you are not eating enough or eating much less than usual

      

you are getting more insulin than you need

      

you are getting a lot of exercise or activity

      

your liver is unable to make enough glucose

      Several diabetes medicines can cause low blood glucose levels, including, of course, insulin. There are other diabetes medicines that can cause relatively high amounts of insulin in the body, which can cause low blood glucose, including a class of drugs called sulfonylureas. Examples of sulfonylureas include chlorpropamide (Diabinese), glyburide (Diabeta, Micronase, and others), glipizide (Glucotrol), and glimepiride (Amaryl). Meal-time agents such as Starlix and Prandin have lower risks for hypoglycemia, but still present some risk. Other diabetes medicines generally do not cause hypoglycemia unless they are taken in combination with medications that increase your risk.

      A common drug associated with hypoglycemia is alcohol. Alcohol has a number of effects that can contribute to low blood glucose levels, and these effects are often delayed up to 12 hours after drinking. Alcohol inhibits the body’s defenses against low blood glucose levels: it blocks the liver’s ability to make glucose, blocks the effects of chemicals (or hormones) in the body that increase glucose production in the liver, blocks the action of insulin (its effectiveness), and impairs your ability to recognize hypoglycemia. Special precautions need to be taken whenever someone with diabetes consumes alcohol. Alcohol consumption and its relation to hypoglycemia are described in depth in Alcohol.

      TREATMENT OF

      HYPOGLYCEMIA

      All low blood glucose levels need to be treated quickly, although the treatment for the different levels of severity (mild or moderate versus severe) varies. If you think you are experiencing hypoglycemia, you should always test your blood glucose level before treating it (unless the low is severe, with unconsciousness or seizure; such cases should be treated before blood glucose is tested).

      Mild or Moderate

      Hypoglycemia

      Confirm mild or moderate hypoglycemia with fingerstick testing (under 70 mg/dl). We recommend using the Rule of 15 to treat mild or moderate hypoglycemia. Treat with 15 grams of carbohydrate; then check the blood glucose level 15 minutes later. Take another 15 grams of carbohydrate if the blood glucose level is not above 70 mg/dl. Depending on a number of factors (such as your actual blood glucose level, plans for exercise, or past experience), you may have to start with 20–30 grams of carbohydrate rather than 15.

       AVOID OVERTREATING HYPOGLYCEMIA

      This is a common mistake for a few reasons. First, people become nervous about a mild or moderate low turning into a severe one. This is especially true for someone who has experienced a severe low event. It can be very scary, not only for the person with diabetes but also for friends and relatives (especially parents of children with diabetes) who witness the event. Plus, if the severe low is experienced in a public place or at work, it can be very embarrassing. People will do anything to avoid this happening again, including over treatment of low blood glucose or intentionally keeping glucose levels higher than goal.

      Second, people have a tendency to treat the symptoms rather than the blood glucose level itself. Sometimes the symptoms take a little longer to recover than the blood glucose: blood glucose levels may be back in the target range (or even above it) after treatment, but some of the symptoms will not have disappeared. If this happens, continuing