What is an example of an upper urinary tract infection: Cystitis, Urethritis, Prostatitis, or Pyelonephritis (infection of the kidney)?

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Last updated: February 24, 2025View editorial policy

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From the Guidelines

Pyelonephritis is the correct answer for an upper urinary tract infection. Pyelonephritis is an infection of the kidney, which is part of the upper urinary tract, as indicated by the European Association of Urology guidelines on urological infections 1. The upper urinary tract consists of the kidneys and ureters, while the lower urinary tract includes the bladder and urethra. Cystitis (bladder infection), urethritis (urethral infection), and prostatitis (prostate infection) are not considered upper urinary tract infections.

Some key characteristics of pyelonephritis include:

  • Presentation with fever (>38 °C), chills, flank pain, nausea, vomiting, or tenderness at the costovertebral angle, with or without symptoms of cystitis 1
  • Diagnosis via urinalysis, urine culture, and antimicrobial susceptibility testing, as well as evaluation of the upper urinary tract via ultrasound to rule out urinary tract obstruction or renal stone disease 1
  • Treatment with fluoroquinolones and cephalosporins for oral empiric treatment of uncomplicated pyelonephritis, with intravenous antimicrobial regimens for patients requiring hospitalization 1

Pyelonephritis is typically more severe than lower urinary tract infections and often requires more aggressive treatment, including hospitalization in some cases. It's usually caused by bacteria ascending from the lower urinary tract, most commonly E. coli. Symptoms of pyelonephritis can include high fever, flank pain, nausea, and vomiting, in addition to the typical symptoms of lower urinary tract infections like frequent and painful urination.

From the FDA Drug Label

Dosing and initial route of therapy (i.e., I.V. or oral) for complicated urinary tract infection or pyelonephritis should be determined by the severity of the infection. Complicated Urinary Tract or Pyelonephritis Intravenous 6 to 10 mg/kg(maximum 400 mgper dose; not to be exceeded even in patients weighing > 51 kg) Every 8 hours 10-21 days* (patients from 1 to 17 years of age)

The answer is Pyelonephritis (infection of the kidney), which is an example of an upper urinary tract infection. 2

From the Research

Upper Urinary Tract Infection Examples

  • Pyelonephritis (infection of the kidney) is an example of an upper urinary tract infection, as stated in studies 3, 4, 5, 6, 7

Characteristics of Pyelonephritis

  • Pyelonephritis is a bacterial infection of the kidney and renal pelvis, and should be suspected in patients with flank pain and laboratory evidence of urinary tract infection 5
  • The most frequent cause of upper urinary tract infection remains E. coli, with other organisms found in complicated infections associated with diabetes mellitus, instrumentation, stone, and immunosuppression 3

Comparison with Other Options

  • Cystitis, Urethritis, and Prostatitis are not examples of upper urinary tract infections, but rather lower urinary tract infections
  • Pyelonephritis is distinct from these conditions, as it involves the kidney and renal pelvis, whereas the other conditions involve the bladder, urethra, or prostate respectively

Diagnosis and Treatment

  • Diagnosis of pyelonephritis is usually straightforward and based on a combination of fever, unilateral flank pain, and a positive urine culture 4
  • Treatment consists of antibiotics, to begin immediately, initially probabilistic and secondarily adapted to the antibiogram 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Management of pyelonephritis and upper urinary tract infections.

The Urologic clinics of North America, 1999

Research

[Management of acute pyelonephritis].

Progres en urologie : journal de l'Association francaise d'urologie et de la Societe francaise d'urologie, 2012

Research

Acute Pyelonephritis in Adults: Rapid Evidence Review.

American family physician, 2020

Research

Pyelonephritis and female urinary tract infection.

Emergency medicine clinics of North America, 1988

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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