Causes of Fasting Hypoglycemia

Fasting hypoglycemia is a type of hypoglycemia, or low blood sugar, that occurs when the stomach is empty. Fasting hypoglycemia is diagnosed as a blood glucose level of less than 50mg/dL, according to the National Diabetes Information Clearinghouse. Symptoms of fasting hypoglycemia include inability to concentrate, lack of energy and headache. It is a normal state when awakening from a night of sleep, after exercising or between meals; however, there are some medications and other underlying conditions that can cause fasting hypoglycemia.

Medications are the most common cause of fasting hypoglycemia, according to the NDIC. These medications include those used to treat diabetes, bacterial infections and severe pneumonia. Some kinds of aspirin taken in large doses can also cause fasting hypoglycemia. When fasting hypoglycemia occurs as a result of medication, it is advised to either change the medication or dosage.

Fasting hypoglycemia that occurs from alcohol intake can occur in those who have consumed alcohol in addition to fasting or heavy exercising or those who are especially sensitive to the effects of alcohol, according to Tufts University. The consumption of alcohol hinders the body's ability to make glucose, which will eventually cause glycogen stores in the body to be depleted. This process takes approximately 12 to 24 hours, after which the symptoms of fasting hypoglycemia become apparent. In order to decrease the probability of fasting hypoglycemia as a result of alcohol intake, food should always be consumed with alcohol.

Liver, heart and kidney disease can be underlying causes for hypoglycemia, according to the NDIC. In these diseased states, the process of gluconeogenesis, which is a metabolic pathway in the body that results in the creation of glucose, is hindered. Sepsis, a bacterial infection in the blood, can also cause fasting hypoglycemia. In these cases, the treatment of the disease or infection will result in normal blood sugar levels.

Hormonal deficiencies that cause fasting hypoglycemia are usually a problem in children rather than in adults. These deficiencies include decreased cortisol, growth hormone, epinephrine or glucagon. Hormone replacement therapy is usually prescribed as a treatment option.

Although rare, insulin-producing tumors in the pancreas called insulinomas can cause fasting hypoglycemia. These tumors may raise insulin levels because there is not enough glucose to balance out this increased insulin. Treatment for insulinomas is complete removal of the tumor, according to Tufts University.