Diabetes Mellitus

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Diabetes MellitusA Brief Introduction

• Presented by
• Rainsville Family Practice
• Thomas L. Horton, MD

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Imagine that this picture represents a blood
vessel in the body
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The blood vessel contains many elements including
red blood cells...
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.. as well as other elements such as proteins,
white blood cells, platelets, and glucose (or
sugar) as represented by the blue shapes in
this picture. Each living cell must come into
contact with at least one blood vessel and
typically uses glucose as fuel.
Cells may be muscle, skin, nerves, or other types
- it really doesnt matter. The principle is the
same.
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When we eat, food is transferred from the
gastrointestinal tract into the blood stream.
Most of this food is converted to fuel, and most
of this fuel is glucose. Some foods are more
easily converted to fuel than others. Refined
sugar is immediately available for use, and
eating sweets or foods with this type compound in
it may cause a rapid and uncontrolled rise in the
concentration of glucose.
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Other foods containing more complex carbohydrates
are also converted to glucose, but it happens at
a more controlled rate so that the body can
transfer the glucose into the cells fast enough
to avoid an abnormal rise in glucose. Bread and
starches are not bad, but they must be taken in
limited amounts to avoid problems.
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A very specific and consistent diet is key to
keeping good glucose control. The diet is
designed to control both the number of calories
and the balance of carbohydrates, fats, and
proteins. All three are necessary for good health.
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It is obvious that the glucose (sugar) must get
into the cell from the blood stream in order to
be burned as fuel.
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Unfortunately, the glucose molecule is too large
to get across the cell membranes and get into the
cell without help. This help comes in the form
of insulin - normally secreted by the pancreas.
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Imagine that insulin acts as key to unlock
tiny doors to allow the glucose to get into the
cells. The more doors that are opened, the more
glucose is pulled out of the blood stream.
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When one checks a glucose, the number obtained
represents how many milligrams of glucose are in
each deciliter of blood (or mg - basically the
concentration of glucose in the blood at that
point in time). The ideal value is somewhere
between 60mg and 110mg in a fasting state (at
least eight hours after eating) and may normally
go as high as 175mg in the first two hours after
eating. During this time, fuel is being
transferred from the G-I tract into the cells for
consumption or storage. Depending on how
efficiently the body is able to accomplish this
transfer, the glucose may fluctuate
substantially. Anything higher than 110mg in a
fasting state or 175mg after eating represents
diabetes mellitus. Many people have the
misconception that the glucose is a steady
number. In truth, it normally changes throughout
the day, depending on diet and activity.
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Diabetes is sometimes related to insulin
resistance. In this case, the pancreas makes
enough insulin, but it is ineffective and cannot
easily unlock the doors. This is called Type II
(adult onset or non-insulin dependent) diabetes.
We generally use pills (oral agents) to help the
bodys own insulin work more effectively. This
condition is typically associated with being
overweight. People often fail to realize that
oral agents do not help immediately lower
glucose. The body uses insulin to lower glucose.
The oral agents simply help the insulin work
better. Therefore, it is not appropriate to take
another pill when glucose is high, nor is it
appropriate to leave off the oral agents because
the glucose is normal or low-normal. The daily
dose of the oral agents needs to remain constant.
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Sometimes, the pancreas simply does not make
enough insulin. This is called Type I (juvenile
or insulin dependent) diabetes. This type
diabetes often results in weight loss - the cells
starve because they cannot get adequate fuel.
We must use extra insulin to treat this. This
currently requires injections because insulin
cannot be given in pills. Stomach acid digests
insulin before it can be absorbed, so it has to
be given by some other route. Efforts are under
way to develop easier ways such as nasal sprays,
but multiple daily injections are todays best
bet. Often, we use a combination of both oral
agents and insulin to get the best results since
people frequently have both insulin resistance
and a relative deficiency of insulin in the body.
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How well are you controlling your glucose? To
understand how the glucose averages over time, we
use another test. Some of the glucose molecules
attach permanently to the red blood cells. Since
the red blood cells typically survive 6-8 weeks,
one can make an estimate of how high the blood
sugar has averaged over the past 6-8 weeks by
measuring the amount of glucose attached to the
red blood cells. The more glucose, the higher the
average. This number is called a hemoglobin A1C.
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We like to see hemoglobin A1C values of about 6.
This indicates very good average control -
glucose values around 110mg. Ultimately, the
cardiovascular consequences of diabetes such as
retinal deterioration, heart attacks, strokes,
peripheral vascular disease, and kidney disease
are dependent on the average glucose, not what it
does occasionally. It has been stated that for
every day the glucose is not well controlled,
ones cardiovascular system ages two days.
Therefore a 50 year old patient with poorly
controlled diabetes for the past 20 years has the
equivalent of a 70 year old heart and
cardiovascular system.