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Hypoglycemia Symptoms, Causes & Treatment
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hypoglicemia
Glucose, a form of sugar, is the body's main fuel. Hypoglycemia, or
low blood sugar, occurs when blood levels of glucose drop too low to fuel
the body's activity.
Carbohydrates (sugars and starches) are the body's main dietary sources
of glucose. During digestion, the glucose is absorbed into the blood
stream (hence the term "blood sugar"), which carries it to every cell in
the body. Unused glucose is stored in the liver as glycogen.
Hypoglycemia can occur as a complication of diabetes, as a condition in
itself, or in association with other disorders.
| Blood Sugar Range
The normal range for blood sugar is about 60 mg/dL (milligrams of
glucose per deciliter of blood) to 120 mg/dL, depending on when a
person last ate. In the fasting state, blood sugar can occasionally
fall below 60 mg/dL and even to below 50 mg/dL and not indicate a
serious abnormality or disease. This can be seen in healthy women,
particularly after prolonged fasting. Blood sugar levels below 45
mg/dL are almost always associated with a serious
abnormality. |
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How Does the Body Control Glucose?
The amount of glucose in the blood is controlled
mainly by the hormones insulin and glucagon. Too much or too little of
these hormones can cause blood sugar levels to fall too low (hypoglycemia)
or rise too high (hyperglycemia). Other hormones that influence blood
sugar levels are cortisol, growth hormone, and catecholamines (epinephrine
and norepinephrine).
The pancreas, a gland in the upper abdomen, produces insulin and
glucagon. The pancreas is dotted with hormone-producing tissue called the
islets of Langerhans, which contain alpha and beta cells. When blood sugar
rises after a meal, the beta cells release insulin. The insulin helps
glucose enter body cells, lowering blood levels of glucose to the normal
range. When blood sugar drops too low, the alpha cells secrete glucagon.
This signals the liver to release stored glycogen and change it back to
glucose, raising blood sugar levels to the normal range. Muscles also
store glycogen that can be converted to glucose.
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Hypoglycemia Symptom
A person with hypoglycemia symptoms may feel weak,
drowsy, confused, hungry, and dizzy. Paleness, headache, irritability,
trembling, sweating, rapid heart beat, and a cold, clammy feeling are also
signs of low blood sugar. In severe cases, a person can lose consciousness
and even lapse into a coma.
Hypoglycemia symptoms are sometimes mistaken for
symptoms caused by conditions not related to blood sugar. For example,
unusual stress and anxiety can cause excess production of catecholamines,
resulting in symptoms similar to those caused by hypoglycemia but having
no relation to blood sugar levels.
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Hypoglycemia in Diabetes
The most common cause of hypoglycemia is as a
complication of diabetes. Diabetes occurs when the body cannot use glucose
for fuel because either the pancreas is not able to make enough insulin or
the insulin that is available is not effective. As a result, glucose
builds up in the blood instead of getting into body cells.
The aim of treatment in diabetes is to lower high blood sugar levels.
To do this, people with diabetes may use insulin or oral drugs, depending
on the type of diabetes they have or the severity of their condition.
Hypoglycemia occurs most often in people who use insulin to lower their
blood sugar. All people with type 1 diabetes and some people with type 2
diabetes use insulin. People with type 2 diabetes who take oral drugs
called sulfonylureas are also vulnerable to low blood sugar episodes.
Conditions that can lead to hypoglycemia in people with diabetes
include taking too much medication, missing or delaying a meal, eating too
little food for the amount of insulin taken, exercising too strenuously,
drinking too much alcohol, or any combination of these factors. People who
have diabetes often refer to hypoglycemia as an "insulin reaction."
Managing Hypoglycemia in Diabetes
People with diabetes should consult their health care providers for
individual guidelines on target blood sugar ranges that are best for them.
The lowest safe blood sugar level for an individual varies, depending on
the person's age, medical condition, and ability to sense hypoglycemia
symptom. A target range that is safe for a young adult with no diabetes
complications, for example, may be too low for a young child or an older
person who may have other medical problems.
Because they are attuned to the hypoglycemia symptoms, people with diabetes can
usually recognize when their blood sugar levels are dropping too low. They
can treat the condition quickly by eating or drinking something with sugar
in it such as candy, juice, or nondiet soda. Taking glucose tablets or
gels (available in drug stores) is another convenient and quick way to
treat hypoglycemia.
People with type 1 diabetes are most vulnerable to severe insulin
reactions, which can cause loss of consciousness. A few patients with
long-standing insulin-dependent diabetes may develop a condition known as
hypoglycemia unawareness, in which they have difficulty recognizing the
symptoms of low blood sugar. For emergency use in patients with type 1
diabetes, physicians often prescribe an injectable form of the hormone
glucagon. A glucagon injection (given by another person) quickly eases hypoglycemia
symptoms of low blood sugar, releasing a burst of glucose into the blood.
Emergency medical help may be needed if the person does not recover in
a few minutes after treatment for hypoglycemia. A person suffering a
severe insulin reaction may be admitted to the hospital so that blood
sugar can be stabilized.
People with diabetes can reduce or prevent episodes of hypoglycemia by
monitoring their blood sugar levels frequently and learning to recognize
a hypoglycemia symptom and the situations that may trigger it.
They should consult their health care providers for advice about the best
way to treat low blood sugar. Friends and relatives should know about the
symptoms of hypoglycemia and how to treat it in case of emergency.
Episodes of hypoglycemia in people with type 1 diabetes may become more
common now that research has shown that carefully controlled blood sugar
helps prevent the complications of diabetes. Keeping blood sugar in a
close-to-normal range requires multiple injections of insulin each day or
use of an insulin pump, frequent testing of blood glucose, a hypoglycemia diet and
exercise plan, and guidance from health care professionals.
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Other Causes of Hypoglycemia
Hypoglycemia in people who do not have diabetes
is far less common than once believed. However, it can occur in some
people under certain conditions such as early pregnancy, prolonged
fasting, and long periods of strenuous exercise. People on beta blocker
medications who exercise are at higher risk of hypoglycemia, and aspirin
can induce hypoglycemia in some children. Drinking alcohol can cause blood
sugar to drop in some sensitive individuals, and hypoglycemia has been
well documented in chronic alcoholics and binge drinkers. Eating unripe
ackee fruit from Jamaica is a rare cause of low blood sugar.
Diagnosis
To diagnose hypoglycemia in people who do not have diabetes, the doctor
looks for the following three conditions:
- The patient complains of hypoglycemia symptoms
- Blood glucose levels are measured while the person is experiencing
those symptoms and found to be 45 mg/dL or less in a woman or 55 mg/dL
or less in a man
- The symptoms are promptly relieved upon ingestion of sugar.
For many years, the oral glucose tolerance test (OGTT) was used
to diagnose hypoglycemia. Experts now realize that the OGTT can actually
trigger hypoglycemia symptoms in people with no signs of the disorder. For
a more accurate diagnosis, experts now recommend that blood sugar be
tested at the same time a person is experiencing a hypoglycemic symptom.
The doctor will also check the patient for health conditions such as
diabetes, obtain a medication history, and assess the degree and severity
of the patient's symptoms. Laboratory tests to measure insulin production
and levels of C-peptide (a substance that the pancreas releases into the
bloodstream in equal amounts to insulin) may be performed.
Reactive Hypoglycemia
A diagnosis of reactive hypoglycemia is considered only after other
possible causes of low blood sugar have been ruled out. Reactive
hypoglycemia with no known cause is a condition in which the symptoms of
low blood sugar appear 2 to 5 hours after eating foods high in glucose.
Ten to 20 years ago, hypoglycemia was a popular diagnosis. However,
studies now show that this condition is actually quite rare. In these
studies, most patients who experienced a hypoglycemia symptom after
eating glucose-rich foods consistently had normal levels of blood
sugar--above 60 mg/dL. Some researchers have suggested that some people
may be extra sensitive to the body's normal release of the hormone
epinephrine after a meal.
People with symptoms of reactive hypoglycemia unrelated to other
medical conditions or problems are usually advised to follow a healthy
eating plan. The doctor or dietitian may suggest a hypoglycemia diet
that avoids foods high in carbohydrates; that the person eat small,
frequent meals and snacks throughout the day; exercise regularly;
and eat a variety of foods, including whole grains, vegetables, and fruits.
Rare Causes of Hypoglycemia
Fasting hypoglycemia occurs when the stomach is empty. It usually
develops in the early morning when a person awakens. As with other forms
of hypoglycemia, the symptoms include headache, lack of energy, and an
inability to concentrate. Fasting hypoglycemia may be caused by a variety
of conditions such as hereditary enzyme or hormone deficiencies, liver
disease, and insulin-producing tumors.
In hereditary fructose intolerance, a disorder usually seen in
children, the body is unable to metabolize the natural sugar fructose.
Attacks of hypoglycemia, marked by seizures, vomiting, and
unconsciousness, are treated by giving glucose and eliminating fructose
from the diet.
Galactosemia, a rare genetic disorder, hampers the body's ability to
process the sugar galactose. An infant with this disorder may appear
normal at birth, but after a few days or weeks of drinking milk (which
contains galactose), the child may begin to vomit, lose weight, and
develop cataracts. The liver may fail to release stored glycogen into the
blood, triggering hypoglycemia. A specific hypoglycemia diet which removes
milk from the diet is the usual treatment.
A deficiency of growth hormone causes increased sensitivity to insulin.
This sensitivity occurs because growth hormone opposes the action of
insulin on muscle and fat cells. For this reason, children with growth
hormone deficiency sometimes suffer from hypoglycemia, which goes away
after treatment.
People with insulin-producing tumors, which arise in the islet cells of
the pancreas, suffer from severe episodes of hypoglycemia.
To diagnose these tumors, called insulinomas, a doctor will put the
patient on a 24- to 72-hour fast while measuring blood levels of glucose,
insulin, and proinsulin. High levels of insulin and proinsulin in the
presence of low levels of glucose strongly suggest an insulin-producing
tumor. These tumors are usually benign and can be surgically removed.
In rare cases, some cancers such as breast cancer and adrenal cancer
may cause hypoglycemia through secretion of a hormone called insulin-like
growth factor II. The treatment is removal of the tumor, if possible.
Keeping on Top of Your Condition
Keeping in tune with your disease or condition not only makes treatment less intimidating but also increases its chance of success, and has been shown to lower a patients risk of complications. As well, as an informed patient, you are better able to discuss your condition and treatment options with your physician.
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Resources on Hypoglycemia
American Diabetes Association (ADA)
National
Service Center
1701 North Beauregard Street
Alexandria, VA
22311
(800) 232-3472 or (703) 549-1500
The ADA is a private, voluntary organization that fosters public
awareness of diabetes and supports and promotes diabetes research and
education. The ADA distributes printed information on many aspects of
diabetes, and local affiliates sponsor community programs. Local
affiliates, located in every state, are listed in telephone directories or
can be located by contacting the national office.
The American Dietetic Association
National Center for Nutrition and
Dietetics
216 West Jackson Boulevard
Chicago, IL 60606-6995
(800)
366-1655 or (312) 899-0040
The American Dietetic Association is a professional organization for
registered dietitians. It publishes a variety of materials for patient and
professional education and supports an information and referral service
for the general public.
Juvenile Diabetes Foundation International
120 Wall Street
New
York, NY 10005-4001
(212) 785-9500 or (800) JDF-CURE
Fax: (212)
785-9595
The JDF is a private, voluntary organization that promotes research and
public education in diabetes, primarily insulin-dependent diabetes. Local
chapters, located across the country, are listed in telephone directories
or can be found by contacting the national office.
National Diabetes Information Clearinghouse (NDIC)
1 Information
Way
Bethesda, MD 20892-3560
(301) 654-3327
The NDIC is a service of NIDDK. The clearinghouse distributes a variety
of diabetes-related materials to the public and to health professionals.
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