Pyelonephritis refers to infection involving both the kidneys and the ureter.  When there is infection in these areas, inflammatory changes will occur leading to a variety of symptoms.  The kidneys and ureters form the upper parts of the urinary tract.  Infections that involve them typically start at the structures lower to them and these include the urinary bladder and urethra.  When infections in these lower parts are not treated immediately, it may spread up and result to pyelonephritis.

Bacteria from the urethra are the most common culprit behind urinary tract infections like pyelonephritis.  These organisms may come from the stool or the environment may invade the urethra and start the inflammatory process.  As the infection spreads upwards, the kidneys and ureters may become affected.  Common symptoms of pyelonephritis include pain in the lower back, hyperthermia, dizziness, and vomiting.  If the infection affects the elderly, some of them may experience body malaise and confusion.  It is also common for patients with pyelonephritis to experience pain during urination.  There will also be an increased urge to urinate and sometimes the urine itself will smell bad or look cloudy.

Simple urinalysis will help diagnose infections in the urinary tract.  In some cases, imaging studies may be needed to pinpoint the exact location of infection and possible formation of stones in the upper parts of the urinary system.  Some doctors may also prescribe blood cultures, and ultrasound to help diagnose and/or classify the type of pyelonephritis.   In terms of treatment, antibiotics are required to stop the bacteria from causing further inflammation.  Most of the time, patients will only need this medication for 1 week while recovering at home.  Serious cases though may need hospitalization and intravenous administration of antibiotics.  For pyelonephritis that caused abscess formation some parts of the kidneys, a medical drainage procedure called nephrostomy may also be necessary.