DIABETES AND ENDOCRINE SYSTEM Endocrine System • Graves' disease • Hypoglycemia • Goiter • Male hypogonadism • Gestational diabetes • Type 1 diabetes • Hyperthyroidism • Hypothyroidism • Addison's disease • Hyperparathyroidism • Diabetic retinopathy • Cushing's syndrome • Acromegaly • Hypopituitarism • Thyroid nodules • Metabolic syndrome • Prolactinoma • Pituitary tumors • Dehydration • Primary aldosteronism • Hashimoto's disease • Pheochromocytoma • Type 2 diabetes • Prediabetes • Diabetic coma • Diabetic hyperosmolar syndrome • Diabetic ketoacidosis • Diabetes insipidus DIABETES AND ENDOCRINE SYSTEM Hypoglycemia • Hypoglycemia

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Hypoglycemia is a condition characterized by an abnormally low level of blood sugar (glucose), your body's main energy source.

Hypoglycemia is commonly associated with diabetes. However, a wide variety of conditions, many of them rare, can cause low blood sugar in people without diabetes. Like fever, hypoglycemia isn't a disease itself, it's an indicator of a health problem.

In people who don't have diabetes, some underlying causes of hypoglycemia include: certain medications; alcohol; certain cancers; critical illnesses such as kidney, liver or heart failure; hormonal deficiencies; and disorders that result in your body producing too much insulin. Insulin is the hormone secreted by your pancreas that regulates your level of blood sugar.

Treatment of hypoglycemia involves short-term steps to get your blood sugar level back into a normal range and long-term steps by your doctor to identify and treat the underlying cause of hypoglycemia.

Your brain needs a steady supply of glucose, for it neither stores nor manufactures its own energy supply. Hypoglycemia can have these effects on your brain:

• Confusion, abnormal behavior or both, such as the inability to complete routine tasks
• Visual disturbances, such as double vision and blurred vision
• Seizures, uncommonly
• Loss of consciousness, uncommonly

Hypoglycemia may also cause these other signs and symptoms:

• Heart palpitations
• Tremor
• Anxiety
• Sweating
• Hunger

These signs and symptoms aren't specific to hypoglycemia. There may be other causes. The only way to know for sure that hypoglycemia is the cause is by having your blood sugar level measured.

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.

Your pancreas is an organ located behind your stomach. When blood glucose levels rise, they signal cells, called beta cells, in your pancreas to release insulin. The insulin, in turn, unlocks your cells so that glucose can enter and also reduces glucose production by your liver. This lowers the amount 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.

When insulin is overproduced
If your pancreas produces and releases too much insulin into your blood, you have a condition called hyperinsulinemia. Hyperinsulinemia isn't a disease; it's an indication of an underlying health problem. When your pancreas releases too much insulin into your bloodstream, even more glucose enters your cells, and your liver can't release glucose into your bloodstream. The result is low blood sugar. In someone without diabetes, the normal range for a fasting blood sugar level is between 70 and 100 milligrams per deciliter (mg/dL). A low fasting blood sugar for someone without diabetes is defined as a level below 50 mg/dL.

Insulin also influences your liver, which plays a key role in maintaining normal blood sugar levels. After you eat, when insulin levels are elevated, your liver accepts extra sugar and stores it in the form of glycogen. Between meals as insulin levels come down, your liver breaks down glycogen (glycogenolysis) and releases glucose into your bloodstream, which keeps your blood sugar level within a narrow and normal range.

Insulin isn't the only factor in the very complex process by which your body attempts to maintain blood sugar in a normal range. Your blood sugar levels can become too low if your body's production of glucose is disrupted. 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, without diabetes
The list of possible specific causes of hypoglycemia in people without diabetes is lengthy. Causes include the following:

• Mistaken use. Taking someone else's oral diabetes medication accidentally is a common cause of hypoglycemia.
• Some medications. Aside from insulin and oral medications used to control diabetes, other medications may cause hypoglycemia, especially in children or in people with kidney failure. One of the most commonly used medications that may have this effect is quinine, which is used to treat leg cramps and malaria.
• Alcohol. Excessive alcohol consumption can block the process of glucose production, depleting your body's stores of glycogen. This usually only occurs if you haven't eaten and are drinking heavily.
• Some critical illnesses. Severe illnesses of the liver, such as drug-induced hepatitis, can cause hypoglycemia because your liver is a key organ in glucose production. The kidney also is an important organ in glucose production, and conditions such as kidney failure affect glucose levels. 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.
• Excessive production of insulin. An excessively high blood insulin level (hyperinsulinemia) may be caused by a rare disorder of the beta cells in your pancreas, where insulin is released. One such disorder is a beta cell tumor, called insulinoma.
• Endocrine deficiencies. Your endocrine system consists of glands that produce hormones that regulate processes throughout your body. They include the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries (in females) and testicles (in males). Certain disorders of the adrenal glands (Addison's disease) and the pituitary gland (hypopituitarism) can result in a deficiency of key hormones that regulate glucose production. Children with these disorders are more prone to hypoglycemia than are adults.
• Other tumors (non-beta-cell tumors). Hypoglycemia may result from tumors other than a beta cell tumor of the pancreas. Some tumors don't cause an overproduction of insulin, but cause excessive utilization of glucose by the tumor or they result in an overproduction of insulin-like substances. Elevated levels of these substances cause hypoglycemia.

Most hypoglycemia occurs 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 is called reactive or postprandial hypoglycemia.

If you have what appear to be symptoms of hypoglycemia, see your doctor. Hypoglycemia can be an indication of any number of illnesses; some of them are potentially serious. By seeing your doctor, you can begin the process of having the underlying illness identified and treated.

To diagnose hypoglycemia, your doctor will use an approach called Whipple's triad, after the American surgeon Allen Whipple. Whipple's triad includes the following factors:

• Signs and symptoms of hypoglycemia. You may not exhibit signs and symptoms of hypoglycemia during your initial visit with your doctor. In this case, your doctor may have you fast overnight in order for hypoglycemic symptoms to occur and so that he or she can make a diagnosis. It's also possible that you'll need to undergo an extended fast in a hospital setting. Or, if your symptoms occur after a meal, your doctor will want to test your glucose levels after a meal.
• Documentation of low blood glucose when the signs and symptoms occur. Your doctor will draw a sample of your blood to be analyzed in the laboratory.
• Disappearance of the signs and symptoms. The third part of the diagnostic triad involves whether your signs and symptoms go away when blood glucose levels are raised.

You'll likely need a physical examination and a review of your medical history with your doctor. He or she will want to determine what medications you use, whether you drink alcohol excessively and whether you have a critical illness. This will help your doctor confirm whether you have hypoglycemia and determine the likely cause.

Treatment of hypoglycemia involves two basic approaches:

• Urgent initial treatment to raise your blood sugar level
• Treatment of the underlying condition that's causing your hypoglycemia, to prevent it from recurring

The initial treatment depends on your symptoms. It may be possible for you to take glucose tablets or eat food or candy to raise your blood sugar level. If your symptoms are more severe, impairing your ability to take sugar by mouth, you may need intravenous glucose or an injection of glucagon.

Because hypoglycemia can have so many causes, preventing recurrent hypoglycemia requires your doctor to identify the underlying condition and treat it. Depending on the underlying cause, treatment may involve:

• Tumor treatment. A tumor in your pancreas or elsewhere is usually treated by surgical removal.
• Medications. If a medication is the cause of your hypoglycemia, your doctor will likely suggest changing the medication.