Definitely. In fact, kidney infections can cause serious, if not life-threatening, health complications when left untreated or not treated correctly! Although this sounds scary, kidney infections are largely avoidable. Our AFC Urgent Care Monroe Road team explains why below, so read on! What Causes a Kidney Infection? Kidney infections usually start with a previous bladder infection that has been left untreated, which then spreads to the kidneys. Bacteria called E. coli are most often the ...