A urinary tract infection (UTI) happens when bacteria (germs) get into the urine and travel into the urinary tract. This causes inflammation (swelling) in part of the urinary tract.

Types of UTI

• A lower UTI is an infection in the lower parts of the urinary tract, the urethra and the bladder. This is called cystitis.
• An upper UTI is an infection in the upper parts of the urinary tract, especially the kidneys. This is called pyelonephritis.

Recurrent UTIs

Some children have recurrent (repeated) UTIs, which keep coming back even after treatment.

These children often have other problems with their urinary system, such as vesicoureteral reflux (VUR). As children with VUR urinate, some urine refluxes (goes back up) towards the kidneys. This makes it easier for germs that cause UTI to travel all the way up to the kidneys, where they cause a more serious infection and illness.