Could a uti affect your kidneys?

Generally no.: Localized infection of the bladder, a uti, is not thought to be dangerous for the kidneys. Sometimes, however, the infection can climb up into the kidneys, but if this happens it is no longer called a uti, it is called pyelonephritis. And, yes, pyelonephritis can potentially damage the kidneys if it is severe or happens repeatedly.

Yes it can: A UTI is an infection anywhere in the urinary tract from urethra all way up to kidney. Som people erroneously think utis are confined to bladder ; below. Most utis go no further than bladder, however bacteria can reach kidneys via ureters due to bladder reflux or bacteria working their way up like mini-caterpillars. Uti affecting kidney is called pyelonephritis ; associated with flank pain.