Treatment for Kidney Infection or Pyelonephritis

Male kidney anatomy, illustration

An estimated 50 to 80 percent of all women develop a urinary tract infection (UTI) at some point in their lives. (Overall, women are far more likely than men to develop UTIs.) The term urinary tract infection is broad and refers to an infection typically caused by bacteria that occurs at any level of the urinary tract: urethra, bladder, ureters, or kidneys.

The Infection Spectrum

Urinary tract infections exist on a spectrum. At one end of the spectrum is asymptomatic bacteriuria, in which bacteria can be found in the urine but no clinical symptoms of infection are present. With most cases of asymptomatic bacteriuria, no treatment is required.

On the other end of the spectrum lies pyelonephritis or kidney infection, which is more serious and the topic of this article. In the middle of the spectrum is symptomatic bacteriuria or cystitis, which is what most people imagine when discussing UTIs. Symptoms of cystitis include pain on urination, cloudy urine, and urgency.

With pyelonephritis, bacteria travels from the urethra up through the bladder and ureter and into the kidney. Fortunately, pyelonephritis involving both kidneys is rare.


Here are some typical symptoms of pyelonephritis:

  • flank pain
  • costovertebral angle tenderness
  • kidney tenderness on deep palpation
  • nausea
  • vomiting
  • fever
  • chills
  • prostration


The clinical diagnosis of pyelonephritis is based on history and physical exam findings as well as laboratory findings from diagnostic tests such as urinalysis and urine culture. Unlike acute uncomplicated cystitis, suspicion of pyelonephritis warrants a urine culture. Diagnostic imaging isn't needed to diagnose most cases of pyelonephritis. Nevertheless, ultrasound and CT can be used to visualize pyelonephritis.

Risk Factors

Risk factors for pyelonephritis are similar to risk factors for all types of UTI and include multiple sexual partners, increased sexual activity, a new sexual partner and a history of recurrent UTIs.


The treatment of pyelonephritis is similar to the treatment of acute cystitis. However, pyelonephritis is more likely than acute cystitis to be caused by antibiotic-resistant bacteria including strains of E. coli that are resistant to Bactrim (TMP-SMX). Thus, treatment of pyelonephritis usually begins with a broad-spectrum antibiotic like ciprofloxacin, and, depending on how nasty the bacteria is that is causing the infection, can include combinations of antibiotics or more potent (big-gun) antibiotics like carbapenem.

Most people who present with uncomplicated pyelonephritis can be treated in the clinic (outpatient). the term uncomplicated means that the patient exhibits no anatomic abnormalities of the urogenital tract, has no instrumentation in a place like an indwelling urinary catheter and is not pregnant. People treated in the clinic for uncomplicated pyelonephritis should be able to tolerate liquids and oral medication.

People with complicated pyelonephritis, recurrent pyelonephritis or comorbidities, such as diabetes or sickle cell disease, are best treated in the hospital. While in the hospital, these people typically receive intravenous antibiotics.

In addition to antibiotics, a person with pyelonephritis can also receive analgesics (think opioids) for pain and promethazine for nausea and vomiting.

Treatment of uncomplicated pyelonephritis lasts about seven days. Complicated or more severe cases of pyelonephritis are treated for about 14 days.

Pyelonephritis is more invasive than acute cystitis, and between 20 and 30 percent of people with pyelonephritis also develop an infection of the blood, too. Other complications of pyelonephritis include cortical necrosis and emphysematous pyelonephritis, where the kidneys are damaged and gas builds up in the kidney, Both of these complications can result in kidney failure.


On a final note, here are some steps that you (a woman) can take to prevent pyelonephritis and UTIs:

  • drink plenty of water
  • void the bladder after sexual intercourse
  • wipe from front to back so as to avoid introduction of bacteria into the vagina
  • urinate frequently
  • avoid feminine hygiene products applied to the genital area like douches and sprays
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Article Sources

  • Gupta K, Trautner BW. Urinary Tract Infections, Pyelonephritis, and Prostatitis. In: Kasper D, Fauci A, Hauser S, Longo D, Jameson J, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 19e. New York, NY: McGraw-Hill; 2015.
  • Howes DS, Bogner MP. Chapter 94. Urinary Tract Infections and Hematuria. In: Tintinalli JE, Stapczynski J, Ma O, Cline DM, Cydulka RK, Meckler GD, T. eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e. New York, NY: McGraw-Hill; 2011.