what causes a kidney infection

A kidney infection, also known as pyelonephritis, is caused by bacteria or viruses that enter the kidneys through the urinary tract. The most common cause of kidney infections is bacteria entering the urinary tract through the urethra and traveling to the kidneys. Bacteria from an infection in another part of the body can also spread through the bloodstream to the kidneys. In rare cases, an artificial joint or heart valve that becomes infected can cause a kidney infection. Women and children are most at risk of developing a kidney infection, as well as other urinary tract infections (UTIs) such as cystitis. Other risk factors include having a weakened immune system, having an abnormality of the urinary tract, or having a condition called vesico-ureteric reflux, where there is a backflow of urine from the bladder up to the kidneys. It is important to seek medical treatment for a kidney infection as soon as possible, as it can lead to dangerous complications such as blood poisoning, damage to the bodys tissues, or death.