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Facts about Diabetes

What is it?

Diabetes mellitus is the name given to a group of conditions linked by the patient's inability to produce and/or utilize insulin. According to the Centers for Disease Control and Prevention (2002 data), about 18 million people in the United States have diabetes, but as many as 5 million of them are not yet aware that diabetes is affecting their health. Diabetes disrupts the normal balance between insulin and glucose. After a meal, carbohydrates usually are broken down into glucose and other simple sugars. This causes blood glucose levels to rise and stimulates the pancreas to release insulin into the bloodstream.

Insulin is a hormone produced by the beta cells in the pancreas. It regulates the transport of glucose into most of the body's cells and works with glucagon, another pancreatic hormone, to maintain blood glucose levels within a narrow range. If there is insufficient or ineffective insulin, or if the body's cells are resistant to its effects ( insulin resistance), glucose levels remain high in the bloodstream and the body's cells "starve." This can cause both acute and chronic problems depending on the severity of the insulin deficiency. Most tissues in the body rely on glucose for energy production and all but a few - such as the brain and nervous system - are entirely reliant on insulin-mediated transportation.

Acute hyperglycemia (high blood glucose levels) can be a medical emergency. The body tries to rid the blood of excess glucose by flushing it out of the system with increased urination. This process can cause dehydration and upset the body's electrolyte balance as sodium and potassium are lost in the urine. Since glucose is not available to the cells, the body attempts to provide an alternate energy source by metabolizing fatty acids. This less efficient process leads to a buildup of ketones (byproducts of fat metabolism) and upsets the body's acid-base balance. Left unchecked, acute hyperglycemia can lead to renal failure, loss of consciousness, and death.

Glucose levels that rise over time and become chronically elevated may not be initially noticed by the patient. The body tries to control the amount of glucose in the blood by increasing insulin production and by excreting glucose in the urine. Symptoms usually begin to arise when the body is no longer able to compensate for the higher levels of blood glucose. Chronic hyperglycemia can cause long-term damage to blood vessels, nerves, and organs throughout the body and can lead to other conditions such as hypertension, strokes, and cardiovascular disease. Damage from hyperglycemia is cumulative and may begin before a patient is aware that he or she has diabetes. The sooner that the condition is detected and treatment started, the better the chances of minimizing complications. 

Three Types

There are three main types of diabetes: type 1, type 2, and gestational diabetes. Pancreatic disease and/or damage can also cause diabetes if the insulin-producing beta cells are destroyed.

Type 1 diabetes , which used to be called insulin dependent or juvenile diabetes, makes up about 10% of the diabetes cases in the United States. Most cases of type 1 diabetes are diagnosed in those under the age of 30. Symptoms often develop abruptly and the diagnosis is often made in an emergency room setting. The patient may be seriously ill, even comatose, with very high glucose levels and high levels of ketones (ketosis). Type 1 diabetics make very little or no insulin. Any insulin-producing beta cells they do have at the time of diagnosis are usually completely destroyed within 5 to 10 years, leaving them entirely reliant on insulin injections to live.

The exact cause of type 1 diabetes is unknown, but a family history of diabetes, viruses that injure the pancreas, and autoimmune processes (where the body's own immune system destroys the beta cells) are all thought to play a role. Type 1 diabetics may have more severe medical complications, sooner than other diabetics. For instance, about 40% of those with type 1 diabetes will develop serious kidney problems leading to kidney failure by the age of 50.

Those with Type 2 diabetes, which used to be known as non-insulin dependent diabetes or adult onset diabetes, do make their own insulin but it is either not in a sufficient amount to meet their needs or their body has become resistant to its effects. At the time of diagnosis, those with type 2 diabetes will frequently have both high glucose levels and high insulin levels, but they may not have any symptoms. About 90% of diabetes cases in the United States are type 2. It generally occurs later in life, in those who are obese, sedentary, and over 45 years of age. Risk factors include:

  • Obesity
  • Lack of exercise
  • Family history of diabetes
  • Pre-diabetes
  • Ethnicity: African-American, Hispanic-American, Native American, Asian-American, Pacific Islander
  • Gestational diabetes during pregnancy or baby weighing more than 9 pounds
  • High blood pressure
  • High triglycerides, high cholesterol, low HDL

Since Americans are becoming more obese and not getting enough regular exercise, the number of those diagnosed with type 2 diabetes is continuing to rise and it is developing at younger ages.

Gestational diabetes is a form of hyperglycemia seen in some pregnant women, usually late in their pregnancy. The cause is unknown, but it is thought that some hormones from the placenta increase insulin resistance in the mother, causing elevated blood glucose levels. Most women are screened for gestational diabetes between their 24th and 28th week of pregnancy. If gestational diabetes is found and not addressed, the baby is likely to be larger than normal, be born with low glucose levels, and be born prematurely. The hyperglycemia associated with gestational diabetes usually goes away after the baby's birth, but both the women diagnosed with gestational diabetes and their babies are at an increased risk of eventually developing type 2 diabetes. A woman who has gestational diabetes with one pregnancy will frequently experience it with subsequent pregnancies.

Pre-Diabetes is a new term for impaired fasting glucose or impaired glucose tolerance. Affecting up to 16 million Americans, pre-diabetes is characterized by glucose levels that are higher than normal, but not high enough to be diagnostic of diabetes. Usually those who have pre-diabetes do not have any symptoms but, if nothing is done to lower their glucose levels, they are at great risk of developing diabetes within about 10 years. Experts are recommending that everyone who has any of the risk factors for type 2 diabetes be tested for pre-diabetes.

Signs and Symptoms

The signs and symptoms of diabetes are related to hyperglycemia, hypoglycemia (temporarily low glucose levels), and complications associated with diabetes. The complications can be related to lipid production, vascular and microvascular damage, organ damage - for example, kidney (diabetic nephropathy), nerve (diabetic neuropathy), and eye (diabetic retinopathy) damage - and/or to the slower healing associated with diabetes. Type 1 diabetics are often diagnosed with acute severe symptoms that require hospitalization. With pre-diabetes, early type 2 diabetes, and gestational diabetes, there usually are no symptoms.

Symptoms of type 1 and type 2 diabetes with hyperglycemia:

  • Increased thirst
  • Increased urination
  • Increased appetite (with type 1, weight loss is also seen)
  • Fatigue
  • Nausea
  • Vomiting
  • Abdominal pain (especially in children)
  • Blurred vision
  • Slow-healing infections
  • Numbness, tingling, and pain in the feet
  • Erectile dysfunction in men
  • Absence of menstruation in women
  • Rapid breathing (acute)
  • Decreased consciousness, coma (acute)

Symptoms of impending hypoglycemia:
 Temporary hypoglycemia in the diabetic may be caused by the accidental injection of too much insulin, not eating enough or waiting too long to eat, exercising strenuously, or by the swings in glucose levels seen with "brittle" diabetes. Hypoglycemia needs to be addressed as soon as it is noticed as it can rapidly progress to unconsciousness. Symptoms include:

  • Sudden severe hunger
  • Headache
  • Anxiety
  • Sweating
  • Confusion
  • Trembling
  • Weakness
  • Double vision
  • Convulsions
  • Coma

Tests

Glucose is the most important test to a diabetic. The fasting blood glucose level is used to screen for and diagnose diabetes and pre-diabetes. It is usually done as part of a regular physical, is ordered when someone has symptoms suggesting diabetes, and is ordered routinely when a person presents to the emergency room with an acute condition.

According to the American Diabetes Association, either a fasting glucose (about an 8 hour fast) or an oral glucose tolerance test (OGTT) may be used to diagnose diabetes and pre-diabetes, but tests should be done at two different times to confirm the diagnosis. The OGTT that they recommend involves a fasting glucose, followed by the patient drinking a standard amount of a glucose solution to "challenge" their system, followed by another glucose test two hours later. Gestational diabetes is diagnosed using a glucose challenge as a screen and then followed by OGTT if the screen is abnormal.

Sometimes random urine samples are "dipsticked" for glucose, protein, and ketones during a physical. If glucose and/or protein or ketones are present on the dipped indicator strip, the patient has a problem that needs to be addressed. This is a screening tool, but it is not sensitive enough for monitoring.

Diabetics must monitor their own blood glucose levels, often several times a day, to determine how far above or below normal their glucose is and, based on their doctor's instructions, what modifications they should make to their medications. This is usually done by placing a drop of blood (obtained by pricking your skin with a small lancet device), onto a glucose strip and then inserting the strip into a glucose meter, a small machine that provides a digital readout of the blood glucose level.

A1c (also called hemoglobin A1c or glycohemoglobin) is a test that is ordered several times a year to monitor patients with type 1 or type 2 diabetes. It is a measure of the average amount of glucose present in the blood over the last 2 to 3 months and helps the doctor to determine how well a treatment plan is working to control the patient's blood glucose levels over time.

Microalbumin, often ordered as a microalbumin/creatinine ratio, is a test that measures very small amounts of protein in the urine (microalbuminuria). This is a symptom of the very early stages of kidney disease. Microalbumin is usually measured annually.

Urine and/or serum ketone tests may be ordered to monitor patients who present at the emergency room with symptoms suggesting acute hyperglycemia and to monitor patients who are being treated for ketosis. A build-up of ketones can occur whenever there is an increase in glucose levels and/or a decrease in the amount or effectiveness of insulin in the body.

Several other laboratory tests may be used to monitor diabetes, evaluate organ function, and detect emerging complications. These include:

To monitor kidney function:
Creatinine Clearance, GFR, EGFR, CMP, BUN, Creatinine, Cystatin C

To monitor cholesterol and other lipids:
Cholesterol, HDL cholesterol, LDL cholesterol, Triglycerides, Lipid profile

To monitor insulin production:
Insulin, C-Peptide

Treatment

While there is no way to prevent type 1 diabetes, the risk of having type 2 diabetes can be greatly decreased by losing excess weight, exercising, and eating a healthy diet with limited fat intake. By identifying pre-diabetic conditions and making the necessary lifestyle changes to lower glucose levels to normal levels, you may be able to prevent type 2 diabetes or delay its onset by several years. Normalizing blood glucose can also minimize or prevent vascular and kidney damage.

There is currently no cure for diabetes, although there has been some limited success with islet (beta) cell transplantations as a way to potentially restore insulin production. The goals of diabetes treatment are to keep glucose levels close to normal and to address any progressive vascular disease or organ damage that arises.

Diabetic treatment at the time of diagnosis is somewhat different than ongoing treatment. Type 1 diabetics are often diagnosed acutely, with very high blood glucose levels, electrolytes out of balance, in a state of diabetic ketoacidosis (where their body has tried to break down fats to use as an alternate fuel source, leading to the toxic build-up of ketones in the blood) with some degree of renal failure. In a worst case scenario, they may have become unconscious and comatose. This is a serious condition requiring immediate hospitalization and expert care to get the body back to its normal balance.

Type 2 diabetics may occasionally encounter something similar if they have ignored initial symptoms, if they have neglected their ongoing treatment, or if they have a serious stress to their system such as a heart attack or stroke, or an infection. Very high blood glucose levels and dehydration reinforce each other, leading to weakness, confusion, convulsions, and to hyperglycemic hyperosmolar coma. This is also a serious condition requiring immediate hospitalization.

Ongoing diabetic treatment revolves around daily glucose monitoring and control, eating a healthy planned diet, and exercising regularly (to lower glucose levels in the blood, increase the body's sensitivity to insulin, and increase circulation). It is important to work closely with your doctor and a diabetes educator, to have regular check ups (several times a year) that include monitoring tests such as microalbumin and hemoglobin A1c, and to get immediate attention for complications. These may include:

Type 1 diabetics must self-check their glucose levels and inject themselves with insulin several times a day. (Insulin is not available in an oral form; it breaks down in the stomach so it must be injected under the skin.). The amount and type of insulin injected must be adjusted to take into account what the patient is eating, the size of their meals, and the amount of activity they are getting. There are several types of insulin available; some are fast-acting and short-lived while others take longer to act but have a longer duration.

Most type 1 diabetics use a combination of insulins to meet their needs, and maintaining control can sometimes be a challenge. Stress, illnesses, and infections can alter the amount of insulin necessary, and some type 1 diabetics have "brittle" control - their glucose levels make rapid swings during the day. A number of type 1 diabetics have turned to wearing insulin pumps, programmable devices that are carried at the waist and provide small amounts of insulin (through a needle under the skin) throughout the day to more closely match normal insulin secretion. As another complicating factor, type 1 diabetics may develop antibodies to insulin over time; their body begins to identify the injections as an "intruder" and works to destroy the insulin, resulting in the necessity of higher doses of insulin or of switching to a different kind.

Type 1 diabetics may also "overshoot," running into trouble with low glucose levels if they inject too much insulin, go extended periods of time without eating, or if their needs change unexpectedly. They must carry glucose with them, in the form of tablets or candy and be ready to take some at the first signs of hypoglycemia (low blood sugar). Carrying glucagon injections (which stimulate the liver to release glucose) is also recommended for times when a patient's hypoglycemia is not responding to oral glucose or for someone else to give them if a patient has become unconscious. Acute conditions, such as diabetic ketoacidosis or renal failure, may require hospitalization to resolve.

Type 2 diabetics usually self check their glucose one or more times a day. Type 2 diabetics are on a continuum, ranging from those who can control their glucose levels with diet and exercise, to those who can take oral medications, to those who need to take daily insulin injections. Many will move along the continuum as their disease progresses. The oral medications available fall into three classes: those that stimulate the pancreas to produce more insulin, those that help make the body more sensitive to the insulin it is producing, and those that slow the absorption of carbohydrates in the stomach (slowing down the post-meal increase in blood glucose). Type 2 diabetics often take two or more of these medications and/or insulin injections - whatever it takes to achieve glucose control.

With gestational diabetes, the mother-to-be will need to eat a modified diet, get regular exercise, and monitor glucose levels as often as her doctor suggests. If more control is needed, she will be given insulin injections (at this time, oral medications are not used). Usually, the diabetic state subsides after birth, although the woman remains at a higher risk of becoming a type 2 diabetic and she should be carefully monitored with any subsequent pregnancies. Right after birth, her baby will be monitored for signs of hypoglycemia and for any respiratory distress.


A1c


 Also known as: Hemoglobin A1c, HbA1c, Glycohemoglobin, Glycated hemoglobin, Glycosylated hemoglobin
Formal name: A1c
Related tests: Glucose test, Microalbumin, Microalbumin/creatinine ratio, Fructosamine


Why get tested?
 To monitor a person's diabetes and to aid in treatment decisions

When to get tested?
 When first diagnosed with diabetes and then 2 to 4 times per year

Sample required?
 A blood sample drawn from a vein in the arm or from a fingerstick

 

What is being tested?
 The A1c test evaluates the average amount of glucose in the blood over the last 2 to 3 months. It does this by measuring the concentration of glycosylated hemoglobin. As glucose circulates in the blood, some of it spontaneously binds to hemoglobin A (the primary form of hemoglobin in adults). Hemoglobin is a red protein that carries oxygen in the red blood cells (RBCs)). Once the glucose is bound to the hemoglobin A, it remains there for the life of the red blood cell (about 120 days). The more glucose that is in the blood, the more that binds to hemoglobin A. This combination of glucose and hemoglobin A is called A1c (or hemoglobin A1c or glycohemoglobin). A1c levels do not change quickly but will shift as older RBCs die and younger ones take their place.

 

How is the sample collected for testing?
 A blood sample is obtained by inserting a needle into a vein in the arm or a drop of blood is taken from your finger by pricking it with a small, pointed lancet.

 

The Test

 

How is it used?
When is it ordered?
What does the test result mean?
Is there anything else I should know?

How is it used?

The A1c test is used primarily to monitor the glucose control of diabetics over time. The goal of those with diabetes is to keep their blood glucose levels as close to normal as possible. This helps to minimize the complications caused by chronically elevated glucose levels, such as progressive damage to body organs like the kidneys, eyes, cardiovascular system, and nerves. The A1c test gives a picture of the average amount of glucose in the blood over the last few months. It can help a patient and his doctor know if the measures they are taking to control the patient's diabetes are successful or need to be adjusted.

The A1c test is frequently ordered on newly diagnosed diabetics to help determine how elevated their uncontrolled blood glucose levels have been. It may be ordered several times while control is being achieved, and then several times a year to verify that good control is being maintained.

 

When is it ordered?

Depending on the type of diabetes that you have, how well your diabetes is controlled, and your doctor, your A1c may be measured 2 to 4 times each year. The American Diabetes Association (ADA) recommends testing your A1c:

  • 4 times each year if you have type 1 or type 2 diabetes and use insulin; or
  • 2 times each year if you have type 2 diabetes and do not use insulin.

When someone is first diagnosed with diabetes or if control is not good, A1c may be ordered more frequently.


What does the test result mean?

A 1% change in an A1c result reflects a change of about 30 mg/dL (1.67 mmol/L) in average blood glucose. For instance, an A1c of 6% corresponds to an average glucose of 135 mg/dL (7.5 mmol/L), while an A1c of 9% corresponds to an average glucose of 240 mg/dL (13.5 mmol/L). The closer a diabetic can keep their A1c to 6%, the better their diabetes is in control. As the A1c increases, so does the risk of complications.

Bear in mind that the correlation between mean plasma glucose (MPG) levels and A1c levels is an estimation only, dependent on methodology used for the calculation as well as other factors, such as the red blood cells life span. The exact MPG value reported on your laboratory report may not coincide exactly with the formula given above.

Is there anything else I should know?

The A1c test will not reflect temporary, acute blood glucose increases or decreases. The glucose swings of someone who has "brittle" diabetes will not be reflected in the A1c.

If you have an abnormal type of hemoglobin, such as sickle cell hemoglobin, you may have a decreased amount of hemoglobin A. This will affect the amount of glucose that can bind to your hemoglobin and may limit the usefulness of the A1c test in monitoring your diabetes. If you have hemolysis or heavy bleeding, your test results may be falsely low. If you are iron deficient, you may have an increased A1c measurement.

Common Questions

1. Is there a home test for A1c?
2. Are all A1c tests the same?


1. Is there a home test for A1c? Yes. There is an FDA-approved test that can be used at home. Unlike some home tests, this one requires a prescription. If you are interested in learning more, please ask your doctor.


2. Are all A1c tests the same? Not yet. There is an international effort underway to standardize A1c tests. Many organizations are working together as part of the National Glycohemoglobin Standardization Program and/or as part of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). Under recent developments:

· The name "A1c" has been recommended as the formal name for the test.

· A reference method proposed by the IFCC is likely to be internationally accepted and promoted as the standard testing method.

· With the IFCC method, doctors and patients will need information and education because the numbers that will be reported (the test results) will be different from those currently used. In the long term, this standardization effort will make A1c testing consistent on an international basis.

· For the short term, current methods (standardized to a method certified in a large clinical study referred to as the DCCT (Diabetes Complications and Control Trial)) and current result reporting will continue to be used.



Source: http://www.labtestsonline.org/understanding/conditions/diabetes.html



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