Any Suggestions?

Hey, I was thinking I’d bring this up, in case any of you have had similar problems and had any good suggestions for me. Over the last week Kolby has started to wet his pants a few times, and I tried to not make a big deal about it the first few times, but when it continued I figured we had to do something to stop the behavior quickly. (I mean, he has been fully potty trained, day and night, for a long time now, so we definitely know that he can do it). I have heard of kids regressing when they are still in the potty training stages, but I didn’t expect it to happen this late. And I know that I had a problem with wetting my pants when I was even older than Kolby – which my mom hated (rightfully so) and I really wanted to quickly get him past this before he formed any kind of a habit or anything. Anyways, we told him that his special blanket would go on time out for more than 1 day if he did it again, and he did. So we put his blanket away for 2 days – he stayed dry for those 2 days and I gave him his blanket back, and then he did it again that afternoon. We took his blanket back away and said he couldn’t have any toys or books in bed when he went for naps or bedtime. He did it again, and we gave him the same punishments, adding to it that he couldn’t color or read his special magnet books during the day. He stayed dry since yesterday, and we had several talks about how everyone gets the same signals that they need to go to the bathroom and we just need to pay attention to those and go when we need to. I also talked to him about choosing the right and choosing the wrong, and good and bad consequences, and he seemed to understand those ideas, and the fact the wetting his pants was choosing the wrong. And this morning I told reminded him about when we got “big boy underwear” for him and how we told him then that he could only have them if he stayed dry, and I told him that I would have to take away his big boy underwear if he kept choosing to do this. (I am running out of ideas for things and privileges to take away from him, since his blanket is his most special possession and I don’t really want to take away preschool or piano lessons, which are his favorite activities). So, when we were changing clothes after church and his pants were wet, I got pretty mad. I spanked him, put a diaper on him, and put him in bed without lunch. It’s frustrating, because talking to him nicely and explaining why we do things and calmly taking away privileges hasn’t seemed to be having any effect. So, I have been thinking today that we should make sure at his 5-year checkup with the doctor tomorrow that he doesn’t have a bladder infection or anything, but assuming that that is not the case, does anyone have any suggestions for us? Staying dry at night doesn’t seem to be his problem, and he has stayed dry for months at a time in the past so we know he has the ability to do it. And reasoning, punishing, and getting mad have not yet helped. I know that this is one of the things that parents have no control over, but it really doesn’t feel like this is a power struggle – he doesn’t seem like he’s doing it just to be naughty. (I’m kind of hoping that the doctor will say it is a bladder infection – although that would make me feel pretty guilty for getting mad at him today, which I already do a little – but that would be something easily fixable. I’m concerned, though, that that won’t be it and we won’t have a quick fix for this problem. So, any suggestions would be appreciated. Thanks!