Pyelonephritis is a bacterial infection of one or both kidneys.

The causes of kidney inflammation: The majority of cases, inflammation of the kidneys caused by bacteria that comes from outside and travel through the urinary system through the urethra to the bladder, and finally from the bladder to the kidneys. In this case it is known as the growing infection. This may explain why women, whose urethra is shorter and closer to the anus, a potential source of bacteria, have four times more represented than men kidney infection.

Escherichia coli, a bacterium that is normally found in the large intestine, causes about 90% of kidney infections in people living within the community, but only about 50% of infections in hospitals. Infections usually occur in ascending through, “climbing” agents in the field of sexual organs in a bubble. With a healthy urinary tract infection edging up in the kidneys, ureter body prevents the fact that urine stream washes out the causes and closing the urethra at the entrance to the place of their entry into the bladder. However, any physical preventing the flow of urine, such as kidney stones or enlargement of the prostate, or the return of urine from the bladder to the urethra increases the chance of kidney infection.