Causes can be divided according to the affected organ and they are Kidney
conditions (infection, pyelonephritis, kidney stones
, polycystic kidney
disease), Bladder conditions (cystitis, bladder polyp, bladder tumor), Urethral conditions (Sexually transmitted diseases, urethral injury) and certain bleeding disorders. When the blood in the urine is at the beginning of urination, it most likely comes from the urethra, (the tube from the bladder to the outside).