February 7, 2011
Diagnosis and Symptoms
Question from Western Massachusetts, USA:
My nine-year-old son was diagnosed with diabetes in October 2010. He had a mildly elevated fasting blood sugar and his OGTT was 230 mg/dl [12.8 mmol/L] at two hours. We have a family history of insulin resistance and his father has type 2. My son has high insulin levels (35), a non-fasting C-Peptide of 6 and acanthosis nigricans He has had significant weight gain due to medication he takes for depression. His initial diagnosis was type 2 and he was put on metformin. Additional blood work came back positive for IAA (5.2) and GAD-65 (1.7) antibodies. The nurse that discussed these results with me said “this shows that he’s type 2” but the nurse practitioner said “this may be type 1 caught very early.” The senior endocrinologist in the group told me “this has us all stumped” and called it “mixed diabetes with characteristics of both types 1 and 2.” He changed the diagnosis to type 1.
The endocrinologist we saw yesterday (same group) first said “some type 2s have antibodies” and then said “there are about 15% of diabetics in a middle group between type 1 and type 2.” (Type 1.5?) Reading research, etc. on the Internet, my impression was that positive antibodies were not found in type 2 and that antibodies pointed toward type 1, which could initially present like type 2 in the early stages.
At diagnosis, my son’s A1c was 6.0. After three months on metformin, it was 5.7. Yesterday, it was 6.1. He has been taking the metformin, exercising and limiting carbohydrates. I am seeing postprandial blood sugars stay elevated in the 160s to 190s mg/dl [8.9 to 11.0 mmol/L] even three and four hours after meals. I am confused by what I see as mixed messages from the “stumped” endocrine team, and would appreciate some input from different eyes. This endocrine team is well respected here in western Massachusetts but I wonder if I should take my son to the Joslin Center in Boston.
Answer:
Your endocrinologist is correct.This is likely what is now called “double diabetes.” Sometimes it is also called type 1.5.
Family history and the blood glucose levels all suggest type 2 diabetes with some insulin resistance. If he were overweight, this would be an added factor. The psychiatric medications often present similarly either directly through insulin resistance and/or obesity or some combination in those who are otherwise genetically susceptible. However, the positive antibodies suggest this is an early form of type 1 diabetes. This is important since antibody positive kids or adults need to go on insulin much sooner than do antibody negative type 2 patients to achieve optimal glucose control.
So, there are aspects of both autoimmune type 1 diabetes where insulin will be required and other aspects of insulin resistance and type 2 diabetes where medications such as metformin would be used. The most important factor right now is to increase daily vigorous activity and promote weight loss while limiting carbohydrate intake. Maximizing the dose of metformin and using the extended release forms sometimes help. The higher post-meal blood glucose level suggest that some other medications or lower glycemic index foods would be helpful. Time will answer the question as to whether or not insulin is needed but this is based upon actual blood glucose results and not dogma. Sometimes switching to another type of psychiatric medication is also helpful, but this depends upon his psychiatric diagnosis, symptoms and response.
SB
