Hypoglycemia

What is hypoglycemia ?

Hypoglycemia, also called low blood glucose or low blood sugar, occurs when blood glucose drops below normal levels. Glucose, an important source of energy for the body, comes from food. Carbohydrates are the main dietary source of glucose. Rice, potatoes, bread, tortillas, cereal, milk, fruit, and sweets are all carbohydrate-rich foods.

After a meal, glucose is absorbed into the bloodstream and carried to the body’s cells. Insulin, a hormone made by the pancreas, helps the cells use glucose for energy. If a person takes in more glucose than the body needs at the time, the body stores the extra glucose in the liver and muscles in a form called glycogen. The body can use glycogen for energy between meals. Extra glucose can also be changed to fat and stored in fat cells. Fat can also be used for energy.

When blood glucose begins to fall, glucagon—another hormone made by the pancreas—signals the liver to break down glycogen and release glucose into the bloodstream. Blood glucose will then rise toward a normal level. In some people with diabetes, this glucagon response to hypoglycemia is impaired and other hormones such as epinephrine, also called adrenaline, may raise the blood glucose level. But with diabetes treated with insulin or pills that increase insulin production, glucose levels can’t easily return to the normal range.

Hypoglycemia can happen suddenly. It is usually mild and can be treated quickly and easily by eating or drinking a small amount of glucose-rich food. If left untreated, hypoglycemia can get worse and cause confusion, clumsiness, or fainting. Severe hypoglycemia can lead to seizures, coma, and even death.

In adults and children older than 10 years, hypoglycemia is uncommon except as a side effect of diabetes treatment. Hypoglycemia can also result, however, from other medications or diseases, hormone or enzyme deficiencies, or tumors.

What causes hypoglycemia ?

Hypoglycemia occurs when your blood sugar (glucose) level falls too low. There are several reasons why this may happen, the most common being a side effect of drugs used for the treatment of diabetes. But to understand how hypoglycemia happens, it helps to know how your body normally regulates blood sugar production, absorption and storage.

Blood sugar regulation
During digestion, your body breaks down carbohydrates from foods — such as bread, rice, pasta, vegetables, fruit and milk products — into various sugar molecules. One of these sugar molecules is glucose, the main energy source for your body. Glucose is absorbed directly into your bloodstream after you eat, but it can't enter the cells of most of your tissues without the help of insulin — a hormone secreted by your pancreas.

When the level of glucose in your blood rises, it signals certain cells (beta cells) in your pancreas, located behind your stomach, to release insulin. The insulin, in turn, unlocks your cells so that glucose can enter and provide the fuel your cells need to function properly. Any extra glucose is stored in your liver and muscles in the form of glycogen. This process lowers the level of glucose in your bloodstream and prevents it from reaching dangerously high levels. As your blood sugar level returns to normal, so does the secretion of insulin from your pancreas.

If you haven't eaten for several hours and your blood sugar level drops, another hormone from your pancreas called glucagon signals your liver to break down the stored glycogen and release glucose back into your bloodstream. This keeps your blood sugar level within a normal range until you eat again.

Aside from your liver breaking down glycogen into glucose, your body also has the ability to manufacture glucose in a process called gluconeogenesis. This process occurs primarily in your liver, but also in your kidneys, and makes use of various substances that are precursors to glucose.

Possible causes, with diabetes

If you have diabetes, the effects of insulin on your body are drastically diminished, either because your pancreas doesn't produce enough of it (type 1 diabetes) or because your cells are less responsive to it (type 2 diabetes). As a result, glucose tends to build up in your bloodstream and may reach dangerously high levels. To correct this problem, you likely take insulin or other drugs designed to lower blood sugar levels.

If you take too much insulin relative to the amount of glucose in your bloodstream, it can cause your blood sugar level to drop too low, resulting in hypoglycemia. Hypoglycemia may also result if, after taking your diabetes medication, you don't eat as much as usual (ingesting less glucose) or you exercise more (using up more glucose) than you normally would. To prevent this from happening, it's likely that your doctor will work with you to find the optimum dosage that fits your regular eating and activity habits.

Possible causes, without diabetes

Hypoglycemia in people without diabetes is much less common. Causes may include the following:

• Medications. Taking someone else's oral diabetes medication accidentally is a possible cause of hypoglycemia. Other medications may cause hypoglycemia, especially in children or in people with kidney failure. One example is quinine, which is used to treat leg cramps as well as malaria.

• Excessive alcohol consumption. Drinking heavily without eating can block your liver from releasing stored glucose into your bloodstream, causing hypoglycemia.

• Some critical illnesses. Severe illnesses of the liver, such as severe hepatitis, can cause hypoglycemia. Disorders of the kidney, which can keep your body from properly excreting medications, can affect glucose levels due to a buildup of those medications. Long-term starvation, as may occur in the eating disorder anorexia nervosa, can result in the depletion of substances your body needs in gluconeogenesis, causing hypoglycemia.

• Tumors. A rare tumor of the pancreas (insulinoma) may cause overproduction of insulin, resulting in hypoglycemia. Other tumors may result in excessive production of insulin-like substances. Or, the tumors themselves may use up too much glucose. Enlargement of beta cells of the pancreas that produce insulin (nesidioblastosis) may result in excessive insulin release, causing hypoglycemia. People who've undergone gastric bypass surgery are at risk of this condition.

• Endocrine deficiencies. Certain disorders of the adrenal glands and the pituitary gland can result in a deficiency of key hormones that regulate glucose production. Children with these disorders are more prone to hypoglycemia than are adults.

Hypoglycemia after meals

Most hypoglycemia occurs when you haven't eaten (when you're in a fasting state), but that's not always the case. Sometimes, hypoglycemia occurs after meals because the body produces more insulin than is needed. This type of hypoglycemia, called reactive or postprandial hypoglycemia, is typical in people who have had gastric bypass surgery.

What is the treatment for hypoglycemia ?

If you feel that your blood glucose is too low, test it. If it is 70 mg/dl or lower, you should eat or drink 15 grams of carbohydrate quickly 1/2 cup of fruit juice, such as:

• 1-2 teaspoons of sugar or honey

• 1/2 cup of regular soda

• 5-6 pieces of hard candy

• Glucose gel or tablets (take the amount noted on the package to add up to 15 grams of carbohydrate)

• 1 cup of milk

• Test your blood sugar again in 15 minutes. If it is still below 70 mg/dl, eat another 15 grams of carbohydrate. If your blood glucose is not low but your next meal is an hour away, have a snack with starch and protein, such as:
  Crackers and peanut butter or cheese
  Half a ham or turkey sandwich
  Crackers or cereal with a cup of milk

The American Diabetes Association (ADA) states that milk is better than juice or glucose because it has lactose, fat and protein that will help keep your blood sugar remain steady over time. A candy bar or other high fat sweets can raise blood sugar too high after you eat them and can contribute to weight gain.

Adult family members should also know how to inject glucagon, a hormone that causes your liver to release glucose. Your doctor can prescribe a glucagon kit. Always keep it in the same place and make sure family and friends know where it is. It is extremely important that those around you know what to do in an emergency.