Most kidney infections start when bacteria enter the tube through which urine leaves the body, the urethra. The germs then multiply and spread to one or both kidneys. Risk factors for a kidney infection include being born female, having a weakened immune system and getting a blocked urinary tract due to a problem such as a kidney stone.

A kidney infection can bring on fever, chills, upset stomach and vomiting. It also can lead to pain in the back, side, groin or belly. Peeing may cause a burning feeling or pain. A person may need to pee often, and the urge to urinate may feel strong and long-lasting. The urine may contain pus or blood, and it might smell bad or look cloudy.

Treatment often includes medicines that stop the growth of bacteria, called antibiotics. Take all the medicine as prescribed. Antibiotics might be given in the hospital if the illness is very serious. Some people also may need surgery to fix a problem with the shape of the urinary tract, which can cause kidney infections to keep coming back.