I didn't know this so I'm just sharing in case it helps someone else.
As a toddler he kept getting high temperatures and tummy aches. They didn't last long but after a few cases I took him to the doctor and explained who said he seemed fine.
This went on a while but by the time I could get him in the temperature had gone.
Then when he was about 3, over a weekend his temp went up sky high and he had febrile convulsions and was admitted with a nearly 42 degree temp. After a lot of waiting around with fans on cold flannels on him they diagnosed a UTI.
A couple of years later he had another sky high temp and manages to get into GP who diagnosed a UTI and sent us off with antibiotics. Two days later we had an apologetic phone call saying that he should have been referred for an ultrasound.
We then went for the ultrasound and the sonographer was pretty shocked how many UTIs he'd had and said he should have been sent the first time. We were then referred on for different scans
We were then referred to a consultant who told us that he had one odd shaped kidney and because of all the UTIs his kidney was scarred and 2/3s of it was no longer functional. He'd also had some damage to his bladder which now couldn't empty properly.
I feel that if I'd known about needing an ultrasound earlier we could have avoided a lot of this, which is why I'm sharing.