Question from Caldwell, Idaho, USA:

My 20 month old son was recently diagnosed with celiac disease. Once on a gluten-free diet, I saw dramatic improvement in his health and energy level. However, I have become increasingly concerned about a few other strange symptoms. He is suddenly exhausted again, sleeping about 18 hours a day, but very lethargic even when he is awake. He is constantly soaking through his diaper and clothes, completely saturating everything every few hours. He is also extremely thirsty, constantly wanting to drink and taking several sippy cups to bed every night. A few weeks ago, I kept track of the amount he drank. It was about 80 ounces in one day. He seems to be drinking slightly less now. Originally, when the symptoms began several months ago, I was told that all this could be his body adjusting to a gluten-free diet, but I am growing more and more concerned as time goes on and especially as I see him becoming increasingly tired and listless. How plausible is the theory that his body is just adjusting now? Or, should I insist that he be tested for diabetes insipidus?