June 10, 2000
Diagnosis and Symptoms
Question from New York, USA:
My 12 year old son was diagnosed over a year ago with possible Type 1 diabetes. He had positive islet cell antibodies and an Insulin level of 18. He is overweight and now we are unsure what type he is. During his last visit to the diabetes clinic, they really got on his case about losing weight. Please help with suggestions. He is on insulin. He is trying to exercise more and will be having more blood work to further determine his type of diabetes.
Every few years, the cause of diabetes is reclassified. In the past, there has been an attempt to divide diabetes into 2 distinct abnormalities.
Type 1 is caused by insulin deficiency. The most common cause of pancreatic failure is an attack on your own pancreas by antibodies that cause an inflammation and destroy the islet cells (autoimmune). Usually, but not always, you can detect antibodies against the pancreas or insulin at the onset of diabetes, or even months or years before the blood sugars become abnormally elevated. The pancreas can normally make much more insulin than is necessary to keep the blood sugar normal. The “classical” onset of type 1 diabetes is weight loss (not explained by dieting), blood sugar over 200, and the presence of ketones in the urine. The diagnosis is usually made due to symptoms of excessive drinking and urination.
Sometimes the diagnosis is made very early, when the patient has no symptoms, has not lost weight, and does not yet have ketones in the urine. This can happen if the person has a routine urine test and is found to have sugar in the urine. If the pancreas is failing, but making enough insulin to prevent the breakdown of fat leading to weight loss and ketones in the urine, the blood sugar may be slightly elevated, but there will have been no weight loss yet or ketones in the urine. Measurement of insulin or c-peptide levels at this time might not be very low as usually seen in type 1 diabetes, but not as high as they should be with an elevated blood sugar. If there are antibodies present in the blood against islet cells or insulin, the diagnosis of type 1 diabetes is usually pretty clear if the person is not overweight.
Type 2 diabetes, is classically caused by resistance to insulin; that is, the person makes insulin, but doesn’t respond to it normally (insulin resistance). The most common cause of insulin resistance is being overweight. All overweight individuals have some degree of insulin resistance, but if they can make enough extra insulin their blood sugars remain normal.
Overweight individuals however, can also develop pancreatic failure (type 1 diabetes). These overweight individuals will magically lose weight before diagnosis, then put it right back on once starting treatment with insulin if they are not careful. If they are overweight, they will also be insulin resistant.
We also are learning that many African American and Hispanic teenagers seem to be developing diabetes that seems to have features of both type 1 and type 2 diabetes. They are overweight before diagnosis, but may develop sudden ketoacidosis and require insulin initially like classical type 1 teens. If their antibodies are negative, however, their insulin requirements may drastically decrease after about a month, and many of them can be treated with diet alone, or with Glucophage [metformin, a pill for Type 2 diabetes], an oral medication that helps your own body’s insulin work better.
We are still trying to sort out all the different types of diabetes, If your son’s antibodies are positive, he most likely has pancreatic failure and will need insulin therapy indefinitely. However, it is important to try to keep his weight normal to avoid secondary insulin resistance. You may want to give the lowest dose of insulin possible that still controls his blood sugar. If you give more than he needs, he will “eat up to the insulin dose” to prevent low blood sugars and gain weight. Exercise is also very important.