What happens when bacteria from kidney/uti infection goes to your blood? and how do you know?

Septicemia: If the infection spread to the blood stream, the person develops high fever, chills, rigors and if left untreated shock and even death. You will know by the worsening symptoms, however, it is better to not wait to let a UTI get that bad. See this site for more info on uti. http://www.webmd.com/a-to-z-guides/urinary-tract-infections-in-teens-and-adults-topic-overview.

Sepsis: When bacteria enter the blood stream due to an infection, that is called "sepsis" (s). Signs of sepsis are a fever and possibly a low bp. Symptoms of s are chills, weakness and fatigue. If one has chills and a temperature > 102 degree f when having a uti, go to an er to be evaluated by a physician for possible sepsis.