According to Sepsis Alliance, an untreated urinary tract infection can lead to a kidney infection, also referred to as pyelonephritis, if the bacteria or fungus that caused initial infection spreads to the kidneys. Left untreated, urinary tract infections also puts individuals at risk for developing sepsis, a severe infection of the bloodstream that is fatal in some cases.
Mayo Clinic explains that untreated urinary tract infections can also cause permanent kidney damage and recurring infections as well as put pregnant women at risk for premature deliveries and low-birth-weight babies. Risk factors for developing urinary tract infections include urinary tract blockages, low estrogen levels due to menopause, and using a diaphragm as a form birth control.
According to MedlinePlus, symptoms of a urinary tract infection that has spread to the kidneys include high fever, chills, nausea, severe stomach pain, groin pain and back pain. Antibiotics often treat mild urinary tract infections and kidney infections successfully, but severe kidney infections may require hospital treatments, such as intravenous antibiotics or surgery. For women with mild urinary tract infections, doctors typically prescribe a three-day course of antibiotics, while men must take the medication for seven to 14 days. Treatment for mild kidney infections and complicated urinary tract infections is also a course of antibiotics for seven to 14 days.