Yes. From the web site of the American Diabetes Association:
When you're sick, you're under stress. To deal with this stress, your body releases hormones that help it fight disease. But these hormones have side effects. They raise blood sugar levels and interfere with the blood sugar-lowering effects of insulin.Most important thing is to drink enough water. Drink a glass an hour -- that's every HOUR -- to avoid dehydration. If you get dehydrated, you can start a nasty syndrome where your kidneys don't have enough fluid to flush glucose from your body. Your BG can get so high that you need to go to the hospital.
DRINK, DRINK, DRINK!