Diabetes Glossary
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A
Acidosis
Too much acid in the body. A person with diabetes whose
disease is not properly controlled will tend to create acidic compounds
called Ketone Bodies. If these cannot be removed from the body, they
will build up to cause a metabolic acidosis called Diabetic Ketoacidosis.
Adult-Onset Diabetes
Former term for non-insulin-dependent diabetes mellitus,
or type 2 diabetes.
Angiopathy
Disease of the blood vessels (arteries, veins and capillaries),
which can result from having diabetes for a long time. Macroangiopathy
and microangiopathy are the two types of angiopathy. In macroangiopathy,
fat and blood clots build up in the large blood vessels, stick to the
vessel walls, and block the flow of blood. In microangiopathy, the walls
of the smaller blood vessels become so thick and weak that they bleed,
leak protein and slow the flow of blood through the body.
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B
Beta
Cell
A type of cell in the pancreas in areas called the islets
of Langerhans. Beta cells make and release insulin, a hormone that controls
the level of glucose (sugar) in the blood.
Blood Glucose
The main sugar used by the body, glucose is a simple
or hexose sugar (one of the smallest kinds of molecules which can be
called a sugar). The glucose found in the bloodstream is mostly derived
from the digestion of complex carbohydrates (starches and the more complex
sugar compounds) but can also be made from fats and proteins. Glucose
is the principal source of energy for living cells, and is carried to
each cell through the bloodstream. Some populations of cells cannot
properly absorb and use glucose except in the presence of insulin. Also
called dextrose.
Blood Sugar
See Blood glucose
Bolus
In Greek, bolus means "lump." In medical contexts,
the word is used to describe a one-time dose of something, given orally
or by injection. In the discussion of diabetes, "bolus" is
usually used to mean a single injection of insulin given to "cover"
an elevated level of blood glucose (sugar), such as the mealtime blood
sugar spike that commonly occurs after eating. Commonly, the size of
this bolus injection of insulin will be determined according to a sliding
scale that "matches" the blood sugar level. Such sliding scales
are generally individualized for each person.
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C
Chronic
glucose toxicity
A chronic exposure to levels of high levels of blood
glucose. Hyperglycemia may not only be a consequence but also a cause
of further impairment in glucose tolerance in the diabetic patient because
hyperglycemia decreases insulin sensitivity in some target tissue populations
and increases glucose production in the liver. Once a patient's metabolic
control improves, the effects of chronic glucose toxicity tend to abate,
and the dose of insulin or hypoglycemic drug can usually be lowered.
Complications of Diabetes
Harmful effects that may happen when a person has diabetes.
Some effects, such as hypoglycemia, can happen any time, particularly
with anti-diabetic medications that have long-lasting effects. Other
complications of diabetes can occur when a person has had diabetes for
a long time, and several organs can be affected and damaged. Damage
to the retina of the eye (retinopathy), the blood vessels (angiopathy),
the nervous system (neuropathy) and the kidneys (nephropathy) are often
the consequence of chronic glucose toxicity. Studies show that keeping
blood glucose levels as close to the normal range as possible may help
prevent, slow, or delay harmful effects to the eyes, kidneys and nerves.
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D
Diabetes
Insipidus
A disease of the pituitary gland or kidney, not to be
confused with diabetes mellitus.
Diabetic Ketoacidosis (DKA)
A severe consequence of out-of-control diabetes, particularly
type 1 diabetes. See Ketoacidosis. DKA is characterized by severe dehydration,
prostration, fever, hypotension, excessively rapid or very deep breathing.
DKA is not caused by blood sugar going too high but by the effects of
"starvation" as certain tissue populations take up abnormal
metabolic processes because they're not being provided with the insulin
they require to make proper use of glucose. DKA is almost always in
need of prompt and appropriate treatment, and can require emergency
care.
Diabetic Retinopathy
A disease of the small blood vessels of the retina of
the eye that can lead to blindness. It is often seen as a complication
of disease in diabetic patients with long-term disease or ineffective
metabolic control.
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E
Euglycemia
A normal level of glucose (sugar) in the blood.
Early Phase Insulin Release
Every time a meal is eaten, blood glucose (sugar) levels
tend to rise. In order to quickly bring the harvest of new glucose into
the cells that require it - and bring blood glucose levels down into
the normal range as soon as possible - the beta cells in the normally-functioning
body will produce an Early Phase Insulin Release which results in higher
levels of blood insulin that "match" the increases in blood
glucose following a meal.
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F
Fasting
Plasma Glucose (FPG)
Also known as fasting blood sugar, the measurement of
plasma glucose generally taken after an overnight fast (the blood sample
drawn early in the morning, with nothing by mouth except water from
about midnight the night before).
Fasting Blood Glucose Test
A method for finding out how much glucose (sugar) is
in the blood. The test can show if a person has diabetes. A blood sample
is taken in a lab or doctor's office. The test is usually done in the
morning before the person has eaten.
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G
Gestational
Diabetes Mellitus (GDM)
A type of diabetes mellitus that can occur when a woman
is pregnant which disappears after the pregnancy ends. Women with GDM
usually develop it during the second half of the pregnancy, but after
the baby is born, the blood sugar goes back to normal levels in 95%
of cases. Women who have had gestational diabetes are at increased risk
for the later development of type 2 diabetes.
Glucagon
A hormone that raises the level of glucose (sugar) in
the blood. The alpha cells of the pancreas (in areas called the islets
of Langerhans) make glucagon when the body needs to put more sugar into
the blood. An injectable form of glucagons is sometimes used to treat
insulin shock. If a patient has insulin shock, the injection glucagon
quickly raises blood glucose back to normal.
Glucose
A simple sugar found in the blood. Glucose is the body's
main source of energy; also known as dextrose.
Glucose Spikes
High levels of blood glucose after meals. Over time,
accumulation of both fasting and post-mealtime glucose spikes can lead
to health complications.
Glucose Tolerance Test
See also Oral Glucose Tolerance Test
A test to see if a person has diabetes. The test is given in a lab or
doctor's office in the morning before the person has eaten. A first
sample of blood is taken from the person. Then the person drinks a liquid
that has glucose (sugar) in it [for an oral glucose tolerance test]
or the patient is given an injection that has a given amount of glucose
in it. After one hour, a second blood sample is drawn, and, after another
hour, a third sample is taken. These tests mimic what happens during
and after a normal meal and allows the doctor to tell if the patient
is able to control the high levels of glucose that a person has after
a meal.
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H
Hemoglobin
A1C (HbA1C)
Hemoglobin is the substance inside red blood cells that
carries oxygen through the bloodstream to the tissues. If the blood
levels of glucose are high, the glucose becomes permanently attached
to the hemoglobin and the glycated (also called glycosylated) hemoglobin
stays inside the red blood cells as long as they live (about 4 months).
Because the HbA1c inside the red blood cells is stable for such a long
time, a test to measure hemoglobin A1C shows what the person's average
blood glucose level was for those 4 months.
Hormone
A chemical released by special cells that turns on, turns
off or fine-tunes what another cell does. Hormones "give orders"
to other cells. For instance, insulin is a hormone made by the beta
cells in the pancreas. When released, insulin "turns on" everything
the cell needs to be able to use glucose (sugar) for energy.
Human Insulin
Man-made insulin compounds that are chemically similar
to insulin produced by the human body.
Hyperglycemia
Too high a level of glucose (sugar) in the blood; a sign
that diabetes is out of control. Many things can cause hyperglycemia.
It occurs when the body does not have enough insulin or cannot effectively
use the insulin it has in order to turn glucose into energy. Signs of
hyperglycemia are a great thirst, a dry mouth, and a need to urinate
more often than usual.
Hyperinsulinism
Too high a level of insulin in the blood. This term most
often refers to a condition in which the body produces too much insulin.
Hypoglycemia
Too low a level of glucose (sugar) in the blood. A person
with hypoglycemia may feel nervous, shaky, weak, sweaty, hungry or may
have a headache or blurred vision. Hypoglycemia occurs when a person
with diabetes has injected too much insulin, taken too high a dose of
an oral anti-diabetic agent, or taken a long-acting oral anti-diabetic.
Hypoglycemia can also happen when a person with diabetes has eaten too
little food or has exercised on an empty stomach.
Impaired Glucose Tolerance (IGT)
Blood glucose (sugar) levels measured from a sample of blood taken after
fasting that are higher than normal but not high enough to be called
diabetes. IGT may be a early warning sign of type 2 diabetes.
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I
Insulin
A hormone that helps the body use glucose (sugar) for
energy. The beta cells of the pancreas (in areas called the islets of
Langerhans) make the insulin. When the body cannot make enough insulin
on its own, a person with diabetes must take a medication that can stimulate
insulin secretion, or improve the way the cells use insulin. Persons
who do not make insulin must inject it into themselves. The insulin
used to be made mostly from pork and beef; now it is more frequently
made from human sources or in the laboratory by recombinant DNA.
Insulin Reaction
Too low a level of glucose (sugar) in the blood; also
called hypoglycemia, caused by injected insulin. This occurs when a
person with diabetes has injected too much insulin, eaten too little
food, or exercised on an empty stomach.
Insulin Receptors
Areas on the outer part of a cell that allow the cell
to join or bind with insulin that is in the blood. When the cell and
insulin bind together, the cell can take glucose (sugar) from the blood
and use it for energy.
Insulin Resistance
The inability of body tissue populations (such as the
fatty cells of the adipose tissue within the abdomen) to respond to
insulin even if there is plenty around. This is a common development
in patients with type 2 diabetes, and it can grow worse as the disease
persists for a long time, particularly when there has been poor metabolic
control.
Insulin Secretion
Insulin is created in the beta cells of the islets of
Langerhans scattered through the pancreas. These beta cells are part
of the endocrine (or "ductless gland") system of the body,
releasing the hormone insulin directly into the bloodstream. In the
normal human body, elevated blood levels of glucose stimulate insulin
secretion. In patients with type 1 diabetes the beta cells have been
destroyed, and the pancreas produces little or no insulin at all. In
patients with type 2 diabetes, the beta cells usually can manufacture
insulin, but the ability of the beta cells to respond to high "spikes"
in blood glucose levels is impaired. Thus, the majority of people with
type 2 diabetes have the ability to make insulin, which could and should
be secreted to help control blood sugar elevations, but that insulin
simply is not appropriately released into the bloodstream.
Insulin Shock
A severe condition resulting from rapid drops in the
level of blood glucose (sugar). The signs are shaking, sweating, dizziness,
double vision, convulsions and collapse. Insulin shock can result when
an insulin reaction is not treated quickly enough.
Islets of Langerhans
The islets of Langerhans are clusters of cells scattered
throughout the abdominal digestive gland called the pancreas. Although
they are in the pancreas and depend upon the pancreas for circulation
and nutrition, they have little to do with the digestive functions of
the pancreas. These "islands" of tissue consist of three cell
types: alpha, beta, and delta. The most abundant cells produce insulin:
the beta cells. The alpha cells make and secrete the hormone glucagons.
The delta cells manufacture the hormone somatostatin.
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K
Ketone
Bodies
Chemicals that the body makes when metabolism is disturbed,
such as during starvation, acute alcoholism, or uncontrolled diabetes
mellitus. It happens when insulin is so low or so poorly utilized that
glucose is not used as the main energy source and the body resorts to
breakdown of fats for energy.
Ketoacidosis
When certain tissue populations in the body can no longer
use glucose for fuel because there's not enough insulin (or insulin
isn't effective enough) to permit them to absorb glucose from the bloodstream,
these "starved" cells begin to create their own fuel by lipid
oxidation, breaking down fat molecules to make energy. Ketone Bodies
(see above) are created as a byproduct. High levels of ketone chemicals
in the bloodstream will cause the blood to become excessively (even
dangerously) acidic and can cause a person to go into a coma.
Ketonuria
Having ketone bodies in the urine; a warning sign of
diabetic ketoacidosis.
Ketosis
A condition of having ketone bodies build up in body
tissues and fluids. The signs of ketosis are nausea, vomiting and stomach
pain. Ketosis can lead to ketoacidosis if the ketone chemicals can't
be eliminated from the body.
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L
Lente
Insulin
A type of insulin with intermediate length of action,
compared to standard or long-acting insulins.
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M
Macrovascular
Disease
A disease of the large blood vessels that sometimes occurs
when a person has had diabetes for a long time. Fat and blood clots
build up in the large blood vessels and stick to the vessel walls. Three
kinds of macrovascular disease are coronary disease, cerebrovascular
disease and peripheral vascular disease.
Microvascular Disease
Disease of the smallest blood vessels that sometimes
occurs when a person has had diabetes for a long time. The walls of
the vessels become abnormally thick but weak, and therefore they bleed,
leak protein and slow the flow of blood through the body.
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N
Nephropathy
Disease of the kidneys caused by damage to the small
blood vessels or to the units in the kidneys that clean the blood.
Neuropathy
Disease of the nervous system. Frequently a person who
has had diabetes for a while may have some signs of nerve damage. The
three major forms of nerve damage are: peripheral neuropathy, autonomic
neuropathy and mononeuropathy.
NPH Insulin
A type of insulin that has an duration of action that
is intermediate compared to standard or long-acting insulins.
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O
Oral
Antidiabetic Agents
See Oral Hypoglycemic Agents
Oral Glucose Tolerance Test (OGTT)
A test to see if a person has diabetes. The test is given
in a lab or doctor's office in the morning before the person has eaten.
A first sample of blood is taken. Then the person drinks a liquid that
has glucose (sugar) in it. After one hour, a second blood sample is
drawn, and, after another hour, a third sample is taken. This test allows
the doctor to tell if the patient is able to control the high levels
of glucose that usually follow eating a meal.
Oral Hypoglycemic Agents7
Pills or capsules that people take by mouth to lower
the level of glucose (sugar) in the blood. The pills work for some people
whose pancreas still makes some insulin. They can help the body in several
ways, such as causing the cells in the pancreas to release more insulin
by improving the functioning of the beta cells in the islets of Langerhans,
or by changing the way glucose is absorbed in the intestines or metabolized
by the liver.
| Drug Class |
Drug Names |
Mechanism of lowering blood glucose |
| Sulfonylurea |
Glyburide
Glimepiride
Glipizide
Chlorpropamide
Tolazamide
Tolbutamide
Acetohexamide |
Stimulates release of insulin from
the pancreas, an effect dependent upon functioning beta cells in
the pancreatic islets |
| Thiazolidinedione |
Rosiglitazone
troglitazone
pioglitazone |
Improves sensitivity to insulin in muscle and adipose
tissue |
| Glucosidase inhibitor |
Acarbose
Miglitol |
Delays digestion of ingested carbohydrates, thus
diminishing the increase in blood sugar after meals by inhibiting
the membrane-bound intestinal alpha-glucosidase hydrolase enzymes |
| Meglitinide |
Repaglinide |
Stimulates the release of insulin from the pancreas
by a different mechanism than the sulfonylureas. |
| Biguanide |
Metformin |
Sensitizes target tissue |
| Phenylalanine derivative |
Nateglinide |
Stimulates pancreas to release insulin in a glucose-dependent
manner; different mechanism than the sulfonylureas. |
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P
Pancreas
An organ behind the lower part of the stomach that is
about the size of the hand. It makes insulin so that the body can use
glucose (sugar) for energy. It also makes enzymes that help the body
digest food. Distributed throughout the pancreas are little clusters
of cells called the islets of Langerhans. The cells in these areas each
have a special purpose. The alpha cells make glucagon, the beta cells
make insulin, and the delta cells make somatostatin.
Pancreas Transplant
A surgical procedure that involves replacing the pancreas
of a person who has diabetes with a healthy pancreas that can make insulin.
The healthy pancreas comes from a donor who has just died. A portion
of the pancreas can be donated by a living relative with suitable tissue
compatibility.
Polydipsia
A great thirst that lasts for long periods of time; a
sign of diabetes.
Polyphagia
Great hunger; a sign of diabetes caused by the "starvation"
of tissue populations which need insulin to make use of glucose. People
with this great hunger often lose weight because the "starving"
tissue populations cannot make use of the new glucose coming into the
bloodstream no matter how much the person eats.
Postmeal (or post-mealtime) Blood Glucose
Blood glucose (sugar) levels taken one to two hours after
eating to determine the amount of glucose (sugar) in the blood following
a meal. Also called postprandial glucose.
Postprandial Glucose (PPG)
(See Postmeal Blood Glucose).
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R
Regular
Insulin
A type of insulin that is fast acting, essentially similar
in onset of action and duration of action to the insulin normally secreted
by the human body's own beta cells.
Retinopathy
A disease of the small blood vessels in the retina of
the eye that can lead to blindness. Retinopathy is often seen as a complication
of disease in patients with diabetes with long-term disease or ineffective
metabolic control.
Risk Factor
Anything that raises the chance that a person will develop
a disease, or sustain an adverse consequence.
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S
Secondary
Diabetes
In addition to "pure" type 1 and type 2 diabetes
mellitus, it is possible for diabetes to develop as a complication of
other diseases. If the pancreas must be surgically removed, for example,
or if the pancreas is damaged or destroyed by inflammation, injury,
infection, or exposure to toxic chemicals, the effect is the same as
if the patient had developed type 1 diabetes. The beta cells in the
islets of Langerhans are no longer available to create and secrete insulin.
A great many other medical conditions can cause type 2 diabetes to develop,
chiefly by causing severe insulin resistance.8 It is important
to distinguish between primary and secondary diabetes because the diseases
causing secondary diabetes must themselves be managed.
Sucrose
Table sugar. Sucrose is a disaccharide, a type of complex
sugar made up of two simple sugars: glucose and fructose. Taken into
the digestive system, sucrose is broken down by enzymes into its two
component simple sugars, and these are absorbed into the blood for use
by the body.
Sugar
A class of carbohydrates that taste sweet. Sugar is a
quick and easy fuel for the body to use. Types of sugar include lactose
("milk sugar"), glucose, fructose, and sucrose.
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T
Type
1 Diabetes Mellitus
Previously known as juvenile diabetes and insulin-dependent
diabetes mellitus (IDDM).
Type 2 Diabetes Mellitus
Previously known as adult-onset diabetes and non-insulin-dependent
diabetes mellitus (NIDDM).
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U
Ultralente
Insulin
A type of insulin that has long action, compared to regular
or intermediate-acting insulin compounds..
Unit of Insulin
Because insulin is measured in units of activity, doses
of insulin are not given by weight or by volume. Today, the most frequently
used concentration of insulin is 100 units per milliliter (mL). A milliliter
is equal to a cubic centimeter (cc). This concentration is called U-100,
and it is the only dosing concentration of insulin in the United States.
In some countries, the older concentrations of U-40 and U-80 (40 units/mL
or 80 units/mL) are still in use, and specialized insulin syringes must
be used to measure doses of these concentrations.9
Unstable Diabetes
A type of diabetes when a person's blood glucose (sugar)
level often swings quickly from high to low and from low to high. Also
called "brittle diabetes" or "labile diabetes."
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References:
1. NIH
Publication No. 94-3016, August 1994.
2. The Expert Committee on the Diagnosis and Classification of Diabetes
Mellitus. Committee Report. Diabetes Care 2000 volume 23 Supplement
1. Accessed at http://journal.diabetes.org
3. See The Merck Manual Online: http://www.merck.com/pubs/mmanual/section2/chapter13/13a.htm#
A002-013-0900
4. Merck Manual Online at http://www.merck.com/pubs/mmanual/section18/chapter251/251g.htm:
"Pregnancy is a metabolic stress test for diabetes; women who fail the
test and develop gestational diabetes may be obese, hyperinsulinemic,
and insulin-resistant or thin and relatively insulin-deficient." In
other words, the development of GDM is an indication that the patient
is inclined toward the development of type 2 diabetes.]
5. Merck Manual Online at http://www.merck.com/pubs/mmanual/section2/chapter13/13a.htm#
A002-013-0900. If the diagnostic qualifiers of type 2 diabetes are not
demonstrably manifest, the patient does not have diabetes mellitus,
but could develop it.]
7. From Mosby's Rx, Harcourt Health Sciences Publishers, 2001. Accessed
at http://www.mosby.com
8. See The Merck Manual Online (http://www.merck.com/pubs/mmanual/section2/chapter13/13a.htm
#A002-013-0900).
9. American Diabetes Association Website "On the Go" (http://www.diabetes.org/ada/c60e.asp)
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