There are some causes of kidney infection. Kidney infections usually happen because of a bladder or urinary tract infection. The bacteria enter through the opening of the urethra and multiply in the bladder. The bacterium moves up through the urinary tract, infecting your bladder, and finally your kidneys.

Some people can develop kidney infection due to the presence of E. Coli en their body.  E. Coli produces 90 % of kidney infections. Changes in the immune system of people suffering from diabetes, AIDS or cancer may increase the risk of kidney infections.

Kidney infections are more frequent in women and may be caused by promiscuous sexual relations or pregnancy.

It is believed that the bacteria can be inadvertently spread from your anus to the urethra, when cleaning your bottom after using the toilet, and the toilet paper comes in contact with genitals.

Bacteria in the urine do not always mean an infection. Some people, especially elder people, may have bacteria in the bladder which do not cause any symptoms or harm and don’t require any treatment. It is known as asymptomatic bacteriuria.

Sometimes, a kidney infection can develop if bacteria or fungi infect the skin, and infection spreads through the bloodstream in the kidney. This only happens in people who have weakened immune systems.

Catheterization, surgery, urinary tract, and other conditions affecting the bladder, such as kidney stones or enlarged prostate are other kidney infection causes.  Rarely, the results after the kidney infection is kidney surgery

Kidney infection may be induced by prostate disease. When the prostate is enlarged or inflamed, it can lead to a backup of urine from the bladder to the kidneys. This can trap bacteria in the urinary tract and can produce bladder and kidney infections. Prostate enlargement is more common in elder people who often do not fight well against against infections, so these infections can be very dangerous for them.

Kidney infection may be developed by narrowing or blockage in the lower urinary. Children may be born with abnormal ureters causing kidney infections being very young.

In pregnancy women are prone to infection of the kidney. Blood in the urine and pain in the side where the kidney is affected are often present in these cases. These infections can result in uterine irritability and preterm labor.

Kidney infection can damage the kidneys or spread through your bloodstream and cause a generalized infection putting your life in risk, if not treated properly. Prompt medical attention is necessary.