1 Bladder infections (urinary tract infections) - Urinary tract infections are very common, and can cause both gross and microscopic hematuria. Often there is pain, but these can be painless, especially in elderly people and children.  Kidney stones - Kidney stones can cause blood in the urine. As these stones travel down the ureters (tube between the kidneys and the bladder) and the bladder they can cause pain which may begin as a dull ache and can progress to severe pain which has been likened to that of childbirth.