While the dawn phenomenon is well documented, have you seen patients who run a high blood glucose after dinner, up to bedtime and perhaps until 1:00 am? The glucose can be 6 mmol/L [108 mg/dl] before dinner at about 6:00 pm, 7 mmol/L [126 mg/dl] after dinner at 8:00 pm (which reflects an inadequate rise and suggests too much bolus from the pump), yet it proceeds to rise to about 10-11 mg/dl [180-198 mmol/L] by about 11:00 pm, though no extra food has been taken after dinner. I have tried to overcome this problem by increasing the basal insulin by 0.1 unit after dinner till about 1:00 am, but I am aware this is different to the usual requirements so would appreciate your thoughts on this.

The dawn phenomenon only describes what occurs with rising growth hormone and cortisol levels overnight and so reflects only the pre-breakfast rising glucose values sometimes seen. It is ore evident during puberty since more growth hormone is being produced and more relative insulin resistance occurs. Other times of the day do not have a specific name, but the same phenomena could likely happen more from insulin waning/running out rather than other hormones causing insulin resistance.It also could happen if more food is eaten at those times.

When using an insulin pump, if there is a prominent dawn phenomenon, then adjustment of basal rate can usually “correct” this problem. If the blood glucose levels start to increase by 5-6:00 am, for instance, then increasing the basal rate an hour or so ahead of this rise will counteract the hyperglycemia. If the rise occurs at 3 am, then increasing the basal rates an hour or so before hand, ie. 1-2 am, should work. The key to overnight control is frequent blood glucose monitoring to identify patterns and then readjustments of either food and/or insulin delivery to counterbalance these patterns.

SB