My teen daughter, 16, has a driver’s license and her numbers have been running high, 300 to 400 mg/dl [16.7 to 22.2 mmol/L], for at least six weeks. We are working with the pediatrician to try to knock them down. In the meantime, I am nervous to let her drive the car with such high blood sugars. I know there are problems with driving and getting low blood sugars, but what are the problems that we might encounter with consistently high blood sugars? If I tell her she can’t drive, she thinks I am punishing her for having high numbers. The truth is, she has outgrown her insulin dose and is doing her part, but this makes me nervous. She has no ketones or DKA but her moods are very erratic. How can I approach this?

Well, I’d suggest that the approach you take be that of firm. I have not uncommonly “warned” my teenage patients that the Division of Motor Vehicles would WELCOME a call or letter from a physician or concerned citizen about a driver whom is questionable. Restrictions can be placed on where/when the person is legally able to drive.

Is it worth it to your child for her driving privileges to be limited simply because she is unwilling to test her glucose, etc.?

So I’d be firm.

That said, as you inferred, HYPOglycemia is more likely to be associated with dramatic changes in judgment or alertness, relative to HYPERglycemia. But, elevated glucose levels can lead to visual changes in the relatively short term (blurred vision, etc). Of course, long-term, poorly controlled diabetes is certainly associated with visual impairment. This is (past the) time to instill good habits.

DS