ICD-10 E16.1 MeSH D007003 | ICD-9-CM 251.2 | |
Reactive hypoglycemia, or postprandial hypoglycemia, is a medical term describing recurrent episodes of symptomatic hypoglycemia occurring within 4 hours after a high carbohydrate meal 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.
Contents
The prevalence of this condition is difficult to ascertain because a number of stricter or looser definitions have been used. It is recommended 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.
To assist diagnosis, a doctor can order an HbA1c test, which measures the blood sugar average over the two or three months before the test. The more specific 6-hour glucose tolerance test can be used to chart changes in the patient's blood sugar levels before ingestion of a special glucose drink and at regular intervals during the six hours following to see if an unusual rise or drop in blood glucose levels occurs.
According to the U.S. National Institute of Health (NIH), a blood glucose level below 70 mg/dL (3.9 mmol/L) at the time of symptoms followed by relief after eating confirms a diagnosis for reactive hypoglycemia.
Signs and 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:
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 believed to be causes, albeit uncommon, of reactive hypoglycemia. myo-Inositol or D-chiro-inositol withdrawal can cause temporary reactive hypoglycemia.
There are different kinds of reactive hypoglycemia:
- Alimentary hypoglycemia (consequence of dumping syndrome; it occurs in about 15% of people who have had stomach surgery)
- Hormonal hypoglycemia (e.g., hypothyroidism)
- Helicobacter pylori-induced gastritis (some reports suggest this bacteria may contribute to the occurrence of reactive hypoglycemia)
- Congenital enzyme deficiencies (hereditary fructose intolerance, galactosemia, and leucine sensitivity of childhood)
- 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 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
Low-carbohydrate diet and/or frequent small split meals is the first treatment of this condition. The first important point is to add small meals at the middle of the morning and of the afternoon, when glycemia would start to decrease. If adequate composition of the meal is found, the fall in blood glucose is thus prevented. Patients should avoid rapidly absorbable sugars and thus avoid popular soft drinks rich in glucose or sucrose. They should also be cautious with drinks associating sugar and alcohol, mainly in the fasting state.
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" — blood glucose levels are normal, but the symptoms are caused through autonomic adrenergic counterregulation. Often, this syndrome is associated with emotional distress and anxious behaviour of the patient. This is often seen in dysautonomic disorders as well. Dietary recommendations for reactive hypoglycemia can help to relieve symptoms of postprandial syndrome.