Welcome at healthcaremagic.
I have read your complete question.The presence of leucocytes
in urine which are more then 5-10 /high power field or significant in number is found in kidney
or bladder infection in maximum no. of cases.In this it will be best in favor of child to get culture of urine done.It will indicate you the culprit behind his symptoms.This will also help you to give you pin point name of antibiotic which should be started for his complete recovery.
Hope this will help you.
With best wishes.