Question from Victoria, British Columbia, Canada:

My four year old son (type 1, diagnosed just before his third birthday) has been battling a stomach flu for a couple of days, even with cutting his insulin dose, he went very low this morning (down to 1.2 mmol/L [21.6 mg/dl] ), and we were faced with his first glucagon injection. Even though he wasn’t unconscious, we felt we couldn’t get him back up fast enough because he was refusing to eat or drink anything. We gave him one-fourth of the regular glucagon dose, he finally woke up after a few hours and went up to 17 mmol/L [306 mg/dl]). I was just considering whether to give him 0.5U of Humalog to bring him down some, when he vomited again. When I checked him 10 minutes after that he was only 9 mmol/L [162 mg/dl]. We’ve been battling these rapid drops with him while he is sick, but usually from 7 mmol/L [126 mg/dl] or so down to the dangerous level. How can blood sugar drop so fast?