a white stringy substance in urine

Hi,

The burning can be caused by the urinary tract infection. How old is your grandson?  The white substance in the urine might be fat cells or protein. And the only thing that can cause this is the malfunction of kidneys. Have he complained of any pain in the kidney area at any time? In my opinion this could be cleared out by antibiotics. Has he seen a doctor already? There are also chances that this can be caused by yeast infection. But if he is too young I am not sure if he could get the yeast infection. His parent should take him to pediatrician and run some test. This might be something serious. I hope this helped a bit.