Encyclopedia Home / P / Pyelonephritis


  • Alternative Names

    Urinary tract infection - complicated; Infection - kidney; Complicated urinary tract infection; Kidney infection


    The goals of treatment are to:

    • Control the infection
    • Relieve symptoms

    Due to the high death rate in the elderly population and the risk of complications, prompt treatment is recommended. Sudden (acute) symptoms usually go away within 48 to 72 hours after appropriate treatment.

    Your doctor will select the appropriate antibiotics after a urine culture identifies the bacteria that is causing the infection. In acute cases, you may receive a 10- to 14-day course of antibiotics.

    If you have a severe infection or cannot take antibiotics by mouth, you may be given antibiotics through a vein (intravenously) at first.

    Chronic pyelonephritis may require long-term antibiotic therapy. It is very important that you finish all the medicine.

    Commonly used antibiotics include the following:

    • Amoxicillin
    • Cephalosporin
    • Levofloxacin and ciprofloxacin
    • Sulfa drugs such as sulfisoxazole/trimethoprim

    Support Groups

    Expectations (prognosis)

    With treatment, most kidney infections get better without complications. However, the treatment may need to be aggressive or prolonged.

    Pregnant women and persons with diabetes or spinal paralysis should have a urine culture after finishing antibiotic therapy to make sure that the bacteria are no longer present in the urine.

    In rare cases, permanent kidney damage can result when:

    • Chronic kidney infections occur in a transplanted kidney
    • Many kidney infections occur during infancy or childhood

    Acute kidney injury (acute renal failure) may occur if a severe infection leads to significantly low blood pressure (shock). The elderly, infants, and persons with a weakened immune system have an increased risk for developing shock and a severe blood infection called sepsis. Often, such patients will be admitted to the hospital for frequent monitoring and IV antibiotics, IV fluids, and other medications as necessary.

    Severe episodes of acute kidney injury may result in permanent kidney damage and lead to chronic kidney disease.

    • Acute kidney failure
    • Kidney infection returns
    • Infection around the kidney (perinephric abscess)
    • Severe blood infection (sepsis)

    Calling your health care provider

    Call your health care provider if you have symptoms of pyelonephritis.

    Call your health care provider if you have been diagnosed with this condition and new symptoms develop, especially:

    • Decreased urine output
    • Persistent high fever
    • Severe flank pain or back pain