Reactive hypoglycemia

Reactive hypoglycemia, or postprandial hypoglycemia, is a medical term describing recurrent episodes of symptomatic hypoglycemia occurring within 4 hours after a high carbohydrate meal (or oral glucose load) in people who do not have diabetes. It is thought to represent a consequence of excessive insulin release triggered by the carbohydrate meal but continuing past the digestion and disposal of the glucose derived from the meal.

The prevalence of this condition is difficult to ascertain and controversial, because a number of stricter or looser definitions have been used, and because many healthy, asymptomatic people can have glucose tolerance test patterns said to be characteristic of reactive hypoglycemia. It has been proposed that the term reactive hypoglycemia be reserved for the pattern of postprandial hypoglycemia which meets the Whipple criteria (symptoms correspond to measurably low glucose and are relieved by raising the glucose), and that the term idiopathic postprandial syndrome be used for similar patterns of symptoms where abnormally low glucose levels at the time of symptoms cannot be documented.

For diagnosis, a doctor can administer an HbA1c test to measure the blood sugar average over the past 2-3 months. Additionally, a 6-hour glucose tolerance test will chart blood sugar during the past six hours.

According to the U.S. National Institute of Health (NIH), a blood glucose level below 70mg/dL at the time of symptoms followed by relief after eating confirms a diagnosis for reactive hypoglycemia.

Common symptoms
Symptoms vary according to individuals' hydration level and sensitivity to the rate and/or magnitude of decline of their blood glucose concentration. Some of the food-induced hypoglycemia symptoms include:
 * heart palpitation or fibrillation
 * fatigue
 * dizziness
 * light-headedness
 * sweating
 * headaches
 * depression
 * nervousness
 * irritability
 * tremors
 * flushing
 * craving sweets
 * increased appetite
 * rhinitis
 * nausea, vomiting
 * panic attack
 * numbness/coldness in the extremities
 * confusion
 * coma can be a result in severe untreated episodes

Causes
The NIH states: "The causes of most cases of reactive hypoglycemia are still open to debate. Some researchers suggest that certain people may be more sensitive to the body’s normal release of the hormone epinephrine, which causes many of the symptoms of hypoglycemia. Others believe deficiencies in glucagon secretion might lead to reactive hypoglycemia."

Stomach surgery or hereditary fructose intolerance are both believed to be causes, albeit uncommon, of reactive hypoglycemia.

Types of reactive hypoglycemia
There are different kinds of reactive hypoglycemia:


 * 1) Alimentary Hypoglycemia (consequence of dumping syndrome; it occurs in about 15% of people who have had stomach surgery)
 * 2) Hormonal Hypoglycemia (e.g., hypothyroidism)
 * 3) Helicobacter pylori-induced gastritis (some reports suggest this bacteria may contribute to the occurrence of reactive hypoglycemia)
 * 4) Congenital enzyme deficiencies (hereditary fructose intolerance, galactosemia, and leucine sensitivity of childhood)
 * 5) Late Hypoglycemia (Occult Diabetes; characterized by a delay in early insulin release from pancreatic β-cells, resulting in initial exaggeration of hyperglycemia during a glucose tolerance test)

"Idiopathic Reactive Hypoglycemia" is a term no longer used because researchers now know the underlying causes of reactive hypoglycemia and have both the tools to perform the diagnosis and the pathophysiological data explaining the mechanisms.

To check if there is real hypoglycemia when symptoms occur, neither an oral glucose tolerance test nor a breakfast test is effective; instead, a hyperglucidic breakfast test or ambulatory glucose testing is the current standard.

Treatment
To relieve reactive hypoglycemia, the NIH recommends taking the following steps :


 * Eating small meals and snacks about every 3 hours;
 * Avoiding or limiting sugar intake;
 * Exercising regularly;
 * Eating a variety of foods, including meat, poultry, fish, or nonmeat sources of protein, foods such as whole-grain bread, fruits, vegetables, and dairy products;
 * Choosing high-fiber foods.

Postprandial syndrome and adrenergic postprandial syndrome
If there is no hypoglycemia at the time of the symptoms, this condition is called "postprandial syndrome." It might be an "adrenergic postprandial syndrome" &mdash; the glycemia is normal, but the symptoms are caused through autonomic adrenergic counterregulation. Often, this syndrome is associated with emotional distress and anxious behaviour of the patient. Dietary recommendations for reactive hypoglycemia can help to relieve symptoms of postprandial syndrome.