Question from Decatur, Illinois, USA:

I apologize if this is long; I want to make sure you have all the details. My 18-year-old son has Down Syndrome and was diagnosed with type 1 diabetes at age 10. He takes 45 units of Lantus at night and NovoLog with meals (his insulin to carbohydrate ratio is 1:8 for breakfast and supper; 1:10 lunch). He also has obsessive-compulsive disorder and other behavior issues for which he takes Abilify and trazodone, plus he takes one-half of a 125 mcg tablet of levothyroxine for hypothyroidism.

Over the past year, he has gained about 10 pounds and, over the past six months, his blood sugar has frequently been higher. His latest A1c was 9.1. When he turned 18, he “outgrew” his pediatric endocrinologist (who was great at not only dealing with his diabetes but also taking into account his other special needs) and she gave us a referral to an adult endocrinologist. When we saw him yesterday, he was very confrontational with me and questioned me extensively about the details of the symptoms at the time of my son’s diagnosis (it’s been eight years–I don’t remember everything!) and then said he thinks my son could have type 2 instead of type 1 (he did not say as well as, but instead of).

My son was not overweight when he was diagnosed. In fact, he was always underweight when he was younger. I became aware of his excessive thirst, frequent urination, tiredness and irritability during family vacation but the symptoms may have begun before that. Since I knew these were symptoms of diabetes, I had his pediatrician check his blood sugar, which was 354 mg/dl [19.7 mmol/L] (fasting) at that time. He was not hospitalized for DKA and never has been, but our new doctor says it is very unusual for children with type 1 to never have been hospitalized with DKA. Is that true? He has ordered blood work to investigate further. The order says GAD-65, IA-2, Insulin Autoantibody Glutamic Acid Decarboxylase and also Islet Cell Ab Scrn Rflx Titer.

I really cannot believe that he could have been misdiagnosed eight years ago. He has seen three different pediatric endocrinologists in that time; surely they would have known if he had been misdiagnosed. What will the doctor be able to tell from these tests? How likely is it that my son has actually had type 2 instead of type 1? I am really worried that the doctor is going to want my son to discontinue his insulin. I also did not like the confrontational way he talked to me and have already contacted our family doctor for a referral to another endocrinologist. Does this seem unreasonable? Am I overreacting?

I am just a little confused and frustrated by all of this. I would appreciate any advice you can give me.