Question from Houston, Texas, USA:

My son is 17 years old and was diagnosed with type 1 just over a year ago. He has had episodes of “low” and has very classic symptoms with them. However, he had a very odd thing happen last night. His blood sugar went from 220 mg/dl [12.2 mmol/L] to 533 mg/dl [29.6 mmol/L] in a couple of hours. We believe this was from bad insulin, insulin that was not effective for some reason. He took Humalog to come down, and refrained from eating, so he wouldn’t go any higher. Within an hour, he was having severe symptoms of being low. However, his blood sugar was still about 400 mg/dl [22.2 mmol/L], then dropped to 356 mg/dl [19.8 mmol/L] pretty quickly. Since he was feeling like he was going to pass out, I treated him as if it were a low. He finally felt better, and his blood sugar stayed at about 450 mg/dl [25 mmol/L] for an hour, and I treated the high. He was completely normal after two hours. Do you think that the symptoms of being low could have been because of the sudden drop in blood sugar? I have never been so confused as to how to treat him. Have you heard of this before?