Diabetes Mellitus
Medical Author: Ruchi Mathur, MD
Medical Editor: William C. Shiel, Jr., MD, FACP, FACR
Diabetes Symptoms
Symptoms of Type II Diabetes
Some of the symptoms of diabetes type II include:
- high amounts of glucose in the urine, which leads to dehydration and causes increased thirst and water consumption;
- weight loss despite an increase in
appetite;
- fatigue;
- nausea;
- vomiting;
- bladder, skin, and vaginal infections;
- blurred vision; and
- lethargy
Read more in-depth information about the symptoms of type II diabetes »
What is diabetes?
Diabetes mellitus is a group of metabolic diseases
characterized by high blood sugar (glucose) levels,
that
result from defects in insulin secretion, or action, or both. Diabetes mellitus,
commonly referred to as diabetes (as it will be in this article) was first
identified as a disease associated with "sweet urine," and excessive muscle loss
in the ancient world. Elevated levels of blood glucose (hyperglycemia) lead to spillage of glucose into the urine, hence the
term sweet urine.
Normally, blood glucose levels are tightly controlled by
insulin, a hormone produced by the
pancreas. Insulin lowers the blood glucose level. When the blood glucose
elevates (for example, after eating food), insulin is released from the pancreas
to normalize the glucose level. In patients with diabetes, the absence or
insufficient production of insulin causes hyperglycemia. Diabetes is a chronic
medical condition, meaning that although it
can be controlled, it lasts a lifetime.
What is the impact of diabetes?
Over time, diabetes can lead to
blindness,
kidney
failure, and nerve damage.
These types of damage are the result of damage to small vessels, referred to as
microvascular disease. Diabetes is also an important factor in accelerating the
hardening and narrowing of the arteries (atherosclerosis),
leading to strokes,
coronary heart disease, and other large blood vessel
diseases. This is referred
to as macrovascular disease.
Diabetes affects approximately 17 million people (about 8% of the population) in
the United States. In addition, an estimated additional 12 million people in the
United States have diabetes and don't even know it.
From an economic
perspective, the total annual cost of diabetes in 1997 was estimated to be 98
billion dollars in the United States. The per capita cost resulting from
diabetes in 1997 amounted to $10,071.00; while healthcare costs for people
without diabetes incurred a per capita cost of $2,699.00. During this same year,
13.9 million days of hospital stay were attributed to diabetes, while
30.3 million physician office visits were diabetes related. Remember, these
numbers reflect only the population in the United States. Globally, the
statistics are staggering.
Diabetes is the third leading cause of death in the
United States after heart disease and cancer.
What causes diabetes?
Insufficient production of insulin (either absolutely or
relative to the body's needs), production of defective insulin (which is
uncommon), or the inability of cells to use insulin properly and efficiently
leads to hyperglycemia and diabetes. This latter condition affects mostly the
cells of muscle and fat tissues, and results in a condition known as
"insulin
resistance." This is the primary problem in type 2 diabetes. The absolute
lack of insulin, usually secondary to a destructive process affecting the
insulin producing beta cells in the pancreas, is the main disorder in type 1
diabetes. In type 2 diabetes, there also is a steady decline of beta cells that
adds to the process of elevated blood sugars. Essentially, if someone is resistant to insulin, the body
can, to some degree, increase production of insulin and overcome the level of
resistance. After time, if production decreases and insulin cannot be released
as vigorously, hyperglycemia develops.
Glucose is a simple sugar found in food. Glucose is an
essential nutrient
that provides energy for the proper functioning of the body cells. Carbohydrates
are broken down in the small intestine and the glucose in digested food is then absorbed by the
intestinal cells into the bloodstream, and is carried by the bloodstream to all
the cells in the body where it is utilized. However, glucose cannot enter the
cells alone and needs insulin to aid in its transport into the
cells. Without insulin, the cells become starved of glucose energy despite the
presence of abundant glucose in the bloodstream. In certain types of diabetes,
the cells' inability to utilize glucose gives rise to the ironic situation of
"starvation in the midst of plenty". The abundant, unutilized glucose is
wastefully excreted in the urine.
Insulin is a hormone that is produced by specialized
cells (beta cells) of the pancreas. (The pancreas is a deep-seated organ in the
abdomen located behind the stomach.) In addition to helping glucose enter the
cells, insulin is also important in tightly regulating the level of glucose in
the blood. After a meal, the blood glucose level rises. In response to the
increased glucose level, the pancreas normally releases more insulin into the
bloodstream to help glucose enter the cells and lower blood glucose levels after
a meal. When the blood glucose levels are lowered, the insulin release from the
pancreas is turned down. It is important to note that even in the fasting state
there is a low steady release of insulin than fluctuates a bit and helps to
maintain a steady blood sugar level during fasting. In normal individuals, such
a regulatory system helps to keep blood glucose levels in a tightly controlled
range. As
outlined above, in patients with diabetes, the insulin is either absent,
relatively insufficient for the body's needs, or not used properly by the body.
All of these factors cause elevated levels of blood glucose (hyperglycemia).
Next: What are the different types of diabetes? »
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