Discussion
There are two primary categories of hypoglycemia: fasting and postprandial (reactive) hypoglycemia. True hypoglycemia (less than 40 mg/dL) releases certain hormones, such as catecholamines, which cause trembling, hunger, dizziness, weakness, headaches, and palpitations. Because many different causes of hypoglycemia exist, treatments are personalized according to the cause.
The most frequent cause of fasting hypoglycemia results from the use of insulin or oral glucose-lowering medications in the treatment of diabetes mellitus. See Medical Nutrition Therapy for Diabetes Mellitus in Section IC. Fasting hypoglycemia may occur in response to not having food for 8 hours or longer. Other less common causes are pancreatic tumors (insulinoma), pancreatic islet cell disease, severe heart failure, and critical organ failure. Certain medications, such as exogenous insulin, sulfonylureas, ethanol, salicylates, pentamidine, quinine, are also noted for causing hypoglycemia in some patients. Diet therapy is the primary treatment, and, in some cases, adjustments in medications also are needed. Surgery may be required to improve the situation for some conditions, such as insulinoma.
Postprandial hypoglycemia is seen most frequently as alimentary hypoglycemia (dumping syndrome) in adults who have undergone gastric surgery, such as Billroth gastrectomy. It usually occurs 1½ to 5 hours after meals, especially carbohydrate-rich meals
Currently, there are no widespread accepted criteria for the diagnosis of reactive hypoglycemia. The techniques range from confirming that the blood glucose level is low when the patient is experiencing a hypoglycemic reaction after an ordinary meal to performing an oral glucose tolerance test (OGTT). However, 10% of asymptomatic healthy persons respond to the OGTT with a lower-than-normal glucose level.
Approaches
Treatment of reactive hypoglycemia depends on the specific cause. Alimentary hypoglycemia following gastric surgery involves treatment. Other modifications that may be helpful are:
- Allow five to six small meals or feedings per day.
- Determine frequency and symptoms of hypoglycemia, activity levels, and exercise for the patient and schedule appropriate times for meals and snacks.
- Use a balanced diet with a mixture of complex carbohydrates, protein, fat, and fiber. The reaction occurs in response to a high carbohydrate load. If necessary, limit carbohydrate to 100 g and increase protein intake accordingly. Use more soluble fibers, such as fruits and vegetables, but avoid concentrated sugar in dried fruit. Carbohydrate counting may be helpful in regulating total carbohydrate intake.
- Limit caffeine, which may reduce cerebral blood flow, and, glucose supply to the brain.
- Limit alcohol because it inhibits gluconeogenesis.
Educate the patient on fast-acting carbohydrate foods that should be used or avoided.
Reference
Reactive hypoglycemia. Manual of Clinical Dietetics. Chicago, Ill: American Dietetic Association; 2000
