Causes of Hypoglycemia

Hypoglycemia is most commonly a complication of diabetes treatment (diabetic hypoglycemia). You can develop hypoglycemia by taking too much insulin or other diabetes medicines.

Hypoglycemia may result from other causes, but these occur much less commonly than diabetes. Other possible causes include:

• Medicines. Some medicines used to treat conditions other than diabetes can cause hypoglycemia or hide its symptoms.
• Too much insulin. Tumors in the pancreas (insulinomas), certain disorders of the pancreas, or some autoimmune diseases can cause too much insulin to be produced. These conditions are rare.
• Illnesses and other health conditions. Hypoglycemia may occur when other diseases and disorders affect the body's sugar metabolism. These can include disorders of the pancreas and endocrine system; diseases of the liver, adrenal glands (such as Addison's disease), or kidneys; heart failure, which can impair liver function; and sepsis. In very rare cases, nonpancreatic tumors cause hypoglycemia.
• Inborn metabolic problems. In rare cases, hypoglycemia may be caused by inherited enzyme or hormone deficiencies, especially those that affect the metabolism of sugars and other carbohydrates. These conditions are often discovered in infancy or childhood.
• Alcohol. In some people, drinking alcohol can cause a drop in blood sugar levels. Hypoglycemia has been associated with chronic alcoholism and binge drinking. Hypoglycemia associated with binge drinking can be particularly severe if a person has not eaten within about 6 hours, because fasting can impair the liver's ability to make new glucose. The person may fall into a coma, which can be fatal.
• Postprandial hypoglycemia. This is also known as alimentary hypoglycemia. Hypoglycemia within 1 to 2 hours after a meal sometimes occurs when stomach contents empty into the intestines too rapidly. This causes the rapid absorption of glucose into the blood and an overproduction of insulin (hyperinsulinism) in response. This problem may occur after surgery for peptic ulcers, obesity, or other stomach problems.
• Other causes. Hypoglycemia also may occur, though rarely, under certain conditions in early pregnancy or with prolonged fasting or missed meals, severe malnutrition, or prolonged strenuous exercise, such as running a marathon. It may occur in premature or full-term newborns with a low birth weight and in newborns whose mothers have been treated for type 1 diabetes or gestational diabetes.