Type 2 Diabetes :: Nationwide Children's Hospital, Columbus, Ohio

Diabetes, Type 2

Definition

Diabetes is a disease that is characterized by a high blood glucose (“sugar”) level.  Type 2 diabetes occurs as a result of “insulin resistance” when the body stops responding normally to insulin.  (On the other hand, type 1 diabetes occurs when the body stops making enough insulin.)

Diagnosis

There are several different ways to diagnose diabetes:

  • A blood glucose of over 200 mg/dl with symptoms of elevated blood glucose (increased thirst, increased urination, increased appetite, unintentional weight loss)

  • Two fasting blood glucose values of 126 mg/dl or higher

  • An oral glucose tolerance test with a two hour blood glucose of 200 mg/dl or higher

  • A hemoglobin A1c measurement of 6.5% or above

Causes

Insulin is produced by the pancreas and secreted into the bloodstream.  It moves glucose out of the blood and into the cells of the body.  Two things are needed for this to happen: insulin needs to be present in the blood, and the cells of the body need to respond to the insulin.  If there is too little insulin produced or too little response to the insulin that is present, then the blood glucose rises and diabetes results.

In type 2 diabetes (also formerly known as Adult Onset Diabetes) the body can produce a normal amount of insulin but the body becomes insensitive to insulin and so needs much more insulin to move the glucose out of the blood.  If the pancreas cannot manage to produce this very high amount of insulin, then the blood glucose rises and results in diabetes.  

There are several things that frequently cause the body to become insensitive to insulin.  One is excess weight, and another is steroid medications such as prednisone or dexamethasone.  Even severe illness can sometimes cause insulin insensitivity and can raise the blood glucose significantly.

Symptoms

High blood glucose levels cause glucose to appear in urine, and this gives many of the initial symptoms.  Glucose in the urine pulls extra fluid into the urine and so there is an increased urine production.  As a result the patient feels thirsty.  Then, if the high blood glucose is not treated adequately, then glucose starts attaching to proteins within the body and causes organ dysfunction.  This particularly affects the eyes, kidneys, heart, blood vessels and nerves.  The best way to completely prevent these problems is by keeping the blood glucose at normal values. 

Sometimes, the body can become so resistant to insulin that it is as if there is no insulin being produced.  This can trigger ketone production.  Ketones bring acid into the blood and can cause life threatening illness that starts with symptoms of dehydration and rapid breathing and often belly pain and can progress to coma.  This is called diabetic ketoacidosis, or DKA.

Treatment

For Type 2 diabetes, if the blood glucose is not too high, then losing weight or going off steroids may cause the blood glucose to return to normal.  But if the blood glucose is very high when type 2 diabetes first hits, which unfortunately is very common in adolescents, then therapy must begin with insulin, just like Type 1 patients.  Modern insulin therapy allows flexibility in size and timing of meals.  About ½ of the daily insulin is given as basal insulin, a low level of insulin that is continuously present in the blood, and about ½ of the daily insulin is divided into boluses given whenever food is eaten to move that glucose from the food out of the blood and into the cells of the body.   Sometimes adolescents with Type 2 diabetes can be weaned off of insulin and be treated for a period of time with pills or non-insulin injections, but frequently these only work for a few years and may require a return to insulin.

Outlook

Currently, diabetes has no cure.  But many researchers around the world are hard at work trying to develop a cure.  Type 2 diabetes can be managed by a combination of weight loss, pills, and/or injections.  If the blood glucose is kept under good control (as indicated by a Hemoglobin A1c level consistently less than 7), then the complications of diabetes do not accumulate, and in fact some can even reverse with time.

Resources

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