Hypoglycemia : (noun)
1: abnormally low blood sugar usually resulting from excessive
insulin or a poor diet [syn: hypoglycaemia] [ant: hyperglycemia]
Based on WordNet 2.0
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Hypoglycemia : What_is_hypoglycemia?__
_Hypoglycemia_means_low_blood_sugar_(glucose)._The_blood__{_glucose"> What is hypoglycemia?
Hypoglycemia means low blood sugar (glucose). The blood { glucose levels in healthy individuals fluctuate depending greatly on the duration of fasting.
The normal range is 70 to 120 mg/dl after an overnight (12 hours) fast. In healthy men, the blood glucose can drop to 55 mg/dl after 24 hours of fasting and to 48 mg/dl after 72 hours of fasting. In
healthy women, glucose levels can be as low as 35 mg/dl after only 24 hours of fasting.
Since blood glucose levels can fluctuate widely in healthy subjects, and symptoms of hypoglycemia can be vague and nonspecific, establishing the diagnosis of hypoglycemia as the cause of symptoms is
often difficult. When symptoms of hypoglycemia occur together with a documented blood glucose under 45 mg/dl, and the symptoms promptly resolve with the administration of glucose, the diagnosis can be
made with more certainty.
What are the symptoms of hypoglycemia?
Hypoglycemia causes the body to release adrenaline. The adrenaline functions to restore and maintain blood glucose levels by mobilizing
stored glycogen and fat, converting them into glucose. In turn, the released adrenaline causes symptoms of nervous system stimulation, such as anxiety, sweating, tremor , palpitations, nausea, and
pallor. Hypoglycemia also starves the brain of glucose energy, which is essential for proper brain function. Lack of glucose energy to the brain can cause symptoms ranging from headache, mild
confusion, and abnormal behavior, to loss of consciousness, seizure, and coma. Severe hypoglycemia can cause death.
Symptoms of hypoglycemia occur at different levels of blood glucose in different patients. In most healthy individuals, symptoms of hypoglycemia may not occur until the glucose level drops below 45
mg/dl. In elderly people, and in patients with chronically high glucose levels (such as patients with poorly controlled diabetes), the symptoms of hypoglycemia can occur at higher glucose levels. In
contrast, patients with chronically low blood glucose may experience hypoglycemic symptoms only at very low glucose levels.
What are the causes of hypoglycemia?
Causes of hypoglycemia include drugs, liver disease, surgical absence of the stomach, tumors that release excess amounts of insulin , and
pre-diabetes. In some patients, symptoms of hypoglycemia occur during fasting (fasting hypoglycemia). In others, symptoms of hypoglycemia occur after meals (reactive hypoglycemia).
Drug-induced hypoglycemia is seen with the inadvertent or intentional overdose of insulin or oral medications used to lower blood glucose. Blood glucose-lowering pills and insulin are medications
used to lower the abnormally high blood glucose levels in patients with diabetes mellitus. Examples of blood glucose-lowering pills are pneumonia infection in patients with AIDS), and Vacor (rat
poison).
The liver stores energy in the form of glycogen. During fasting, glycogen is broken down and converted into glucose. This glycogen conversion into glucose is important in maintaining the blood
glucose level. Therefore, during fasting, maintenance of the blood glucose level depends more on glycogen conversion than on sugars we eat. In severe liver disease, this mechanism can be disrupted,
leading to hypoglycemia. Kidney failure also can lead to hypoglycemia, especially when the person is deprived of food.
Insulin is a hormone produced by the pancreas to regulate the blood glucose level. In contrast to adrenaline, insulin decreases the blood glucose level. As the blood glucose level rises after a
meal, insulin is released by the pancreas to lower the glucose level. As the blood glucose falls, the insulin released from the pancreas decreases. Therefore, insulin is part of the regulatory system
of the body that maintains the blood glucose in the normal range. Insulinoma is a rare tumor of the pancreas that releases a large amount of insulin without regulation. Patients with insulinomas can
develop severe hypoglycemia. Special blood and radiological studies (such as CAT scan or magnetic resonance imaging (MRI))are required to diagnose and locate the insulinoma. Treatment consists of
removing the tumor with surgery. Other cancers in the body can also produce hormones similar to insulin that cause fasting hypoglycemia.
Reactive hypoglycemia refers to hypoglycemia that occurs after a meal. Reactive hypoglycemia can be seen in patients who have had surgical removal of the stomach (gastrectomy). In the absence of a
stomach, glucose in the meal is rapidly absorbed into the blood stream through the intestines, causing sudden hyperglycemia (high blood glucose). In order to correct this sudden hyperglycemia,
excessive amounts of insulin are released by the pancreas, which drives the blood glucose down, causing hypoglycemia. The reactive hypoglycemia in gastrectomy patients occurs early, usually within 1
hour after a meal.
Another cause of reactive hypoglycemia is early diabetes mellitus. The hypoglycemia occurs late, usually 3-5 hours after meals. The late reactive hypoglycemia seen in diabetes is due to the delay in
insulin released from the pancreas. Patients with late reactive hypoglycemia tend to be obese and have a family history of diabetes mellitus .
Some patients have symptoms of reactive hypoglycemia without having had gastrectomy or a family history of diabetes mellitus. These patients tend to have associated symptoms of chronic fatigue,
weakness, anxiety, poor concentration, headaches, hunger, and tremors after meals. They are often diagnosed as having reactive hypoglycemia of unknown cause. Complete blood tests and physical
examinations are typically normal in these patients. Often, a 5-hour glucose tolerance test (100 grams of glucose is given by mouth and the glucose is measured every hour for five hours) shows low
blood glucose at 3-5 hours after glucose ingestion. Traditionally, it has been assumed that the low blood glucose level causes the patient's symptoms. However, many endocrinologists now question the
validity of the glucose tolerance test in the diagnosis of reactive hypoglycemia of unknown cause. As many as one third of normal individuals have low blood glucose during a 5-hour glucose tolerance
test, and may not develop any symptoms. Conversely, patients with reactive hypoglycemia can have normal glucose hours after regular meals.
How is hypoglycemia diagnosed?
Blood glucose can be easily measured by blood testing in a doctor's office. Home test kits are also available for rapid glucose measurement. These
home test kits are designed for use by diabetics to monitor and regulate their blood glucose at home while taking insulin or oral glucose-lowering agents.
Since symptoms of hypoglycemia are vague and often non- specific, many other conditions can mimic hypoglycemia. In order to establish hypoglycemia as the cause of the patient's symptoms, three
criteria must be met. The patient must have symptoms of hypoglycemia with a documented blood glucose level of less than 45 mg/dl. Additionally, the symptoms have to resolve completely with the
administration of glucose. These diagnostic criteria are referred to as "Whipple's triad."
When medications, such as diabetes medicines, cause hypoglycemia, it can be discovered by reviewing the patient's history of taking excessive medication, or by measurement of the level of
medications in the blood. When insulin-producing tumors are responsible for hypoglycemia the diagnosis can be made by finding excess insulin and its byproducts in the blood.
In patients suspected of having reactive hypoglycemia, the 5- hour glucose tolerance test is not as useful as directly measuring the blood glucose levels or performing home glucose monitoring when
symptoms occur.
How is hypoglycemia treated?
Treatment of hypoglycemia requires identification of the underlying cause. Medications causing hypoglycemia should be discontinued. Underlying liver
and kidney disease may need to be managed. Insulin- producing tumors are localized with radiological tests and surgically removed.
If the patient is alert, immediate treatment of severe hypoglycemia consists of administering large amounts of glucose, and repeating this treatment at intervals if the symptoms persist.
Self-monitoring of glucose prior to treatment is important to document hypoglycemia. Since neurological deterioration can occur rapidly, treatment of severe hypoglycemia is undertaken without delay.
When more urgent treatment is required due to deteriorating neurological symptoms, an intravenous glucose injection is administered.
Patients with diabetes mellitus who develop low blood glucose from their medicines require medication adjustments. Treatment of reactive hypoglycemia, on the other hand, consists of dietary
measures, including fewer concentrated sweets and the ingestion of multiple small meals throughout the day. - Hypoglycemia means low blood
sugar (glucose).
- Hypoglycemia is only significant when it is associated with symptoms.
- Hypoglycemia has many causes including drugs, liver disease, surgical absence of the stomach,
pre-diabetes, and rare tumors that release excess insulin.
- Hypoglycemia treatment is directed first at the underlying cause.
Based on University of Miami School of Medicine [Medical_Dictionary]:
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Hypoglycemia : Hypoglycemia : Low blood sugar (glucose). When symptoms of hypoglycemia occur together with a documented blood glucose under 45 mg/dl, and the symptoms promptly resolve with the
administration of glucose, the diagnosis of hypoglycemia can be made with some certainty. Hypoglycemia is only significant when it is associated with symptoms.
The symptoms may include anxiety, sweating, tremor, palpitations, nausea, and pallor. Hypoglycemia also starves the brain of glucose energy, which is essential for proper brain function. Lack of
glucose energy to the brain can cause symptoms ranging from headache, mild confusion, and abnormal behavior, to loss of consciousness, seizure, and coma. Severe hypoglycemia can cause death.
The causes of hypoglycemia include drugs (such as insulin), liver disease, surgical absence of the stomach, tumors that release excess amounts of insulin, and pre-diabetes. In some patients,
symptoms of hypoglycemia occur during fasting (fasting hypoglycemia). In others, symptoms of hypoglycemia occur after meals (reactive hypoglycemia).
Immediate treatment of severe hypoglycemia consists of administering large amounts of glucose, and repeating this treatment at intervals if the symptoms persist. Treatment must also be directed at
the underlying cause. Patients with diabetes mellitus who develop low blood glucose from their medicines require medication adjustments. Treatment of reactive hypoglycemia consists of dietary measures,
including fewer concentrated sweets and the ingestion of multiple small meals throughout the day.
Based on University of Miami School of Medicine [Medical_Dictionary]:
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