My nine year old daughter, diagnosed seven months ago, uses Humalog, Regular, and NPH in the morning and Regular and NPH at dinnertime. She is now out of the honeymoon phase and her daytime numbers are generally good with a hemoglobin A1c of 6.8%, but we have noticed that the closer she gets to her 2:30 am goal of around 80 mg/dl [4.4 mmol/L], the higher she is in the morning. I understand the dawn phenomenon, and almost all along I noticed when her dinner NPH was increased she got higher in the morning. She is not rebounding because we have checked her throughout the night.

Last night she was 77 mg/dl [4.3 mmol/L] at 2:30 am and woke up at 214 mg/dl [11.9 mmol/L]. The other night she was 160 mg/dl [8.9 mmol/L] at 11:00 pm, 161 mg/dl [8.9 mmol/L] at 2:30 am, and she woke up at 157 mg/dl [8.7 mmol/L]. Is it normal for the dawn phenomenon to be more dramatic the lower the blood sugar goes? What changes would you suggest?

I am a bit uncertain where the value of 80 mg/dl [4.4 mmol/L] came from for the 2:30 am glucose check. I rarely have my established patients routinely check early morning like that. Do you awaken her and give her a snack at that time? Does she have a bedtime snack? As for the goal of 80 mg/dl [4.4 mmol/L], that actually seems a bit “tight” for my tastes. You may want to confirm these values and need to check with your daughter’s diabetes team. Sometimes one does need to check early morning values like that, but generally not on an regular basis. Some parents are very obsessive to check. I think that as the child becomes a teen (and often with some rebelliousness) and more independent, this type of scrutiny may lead to defiance and poorer glycemic control. (I’m not saying this will happen, but you need to pick your battles.) Besides, no one gets good sleep with those middle-of-the-night checks.

Finally, I think you need to reassess the meal plan/snack situation relative to her insulin dose. You may well be seeing rebound hyperglycemia (more properly referred to as the Somogyi Effect effect) hypoglycemia begets hyperglycemia. This is different, albeit subtly, from the dawn phenomenon. The dawn phenomenon occurs with the normal, physiologic changes occurring prior to awakening, related to normal increases in cortisol and growth hormone (and other substances). The Somogyi effect also involves those types of insulin- counteractive hormones but occurs in a somewhat exaggerated way to combat hypoglycemia.

So, if you find that increased evening NPH leads to higher fasting glucoses, (which is the classic description of the Somogyi effect), I’d suggest you cut back on your daughter’s evening NPH, loosen (if not ignore) your “target” for the 2:30 AM check. Certainly check with your daughter’s diabetes team.

DS

[Editor’s comment: We ran a poll on the subject of middle-of-the-night testing in December 2001. Results indicated that 25% of families reported testing every night.

JSH]