5 year old suddently peeing the bed

So, Matthew was nighttime potty trained around May/June. He was doing great with only the very occasional accident until nearly 3 weeks ago. Since then, he's been peeing the bed EVERY night. Nothing has changed in eating/drinking habits. We've had to put him back in pull ups, which he's not thrilled about, but we just couldn't change any more sheets in the middle of the night. Anyone else ever been through this? Advice?

 

Has he been sick or emotional? We have had coughing cause wet sheets in the morning. Does he ever get up during the night to go? He could be just sleeping thru when he normally gets up

 

I don't have any suggestions, but can totally relate. My DD was completely day and night trained before she was 3, with maybe 1-2 accidents/mo. Then her baby brother was born (like 9-10 months later) and suddenly wet every single night. That's been 17 months, and she's over the issues of being replaced as the youngest (yes, she's a twin, but being so small and being legally blind, she was and still sometimes is kind of babied--though I tried not to). But still, the only way she'll wake up dry is if I happen to wake her up sometime after midnight to go to the bathroom. I don't always remember, and even if I do, it doesn't always work. So she wets the bed 4-5 nights/week, if not in pullups. I don't know why. Ug.

 

Could he have a UTI or other medical issue?