Guidelines
Pyelonephritis

Pyelonephritis

Definition

  • Bacterial infection of the kidney/upper urinary tract
  • Considered complicated if structural or functional abnormality

Diagnosis

  • Flank pain
  • Fever
  • Chills
  • Nausea
  • Vomiting
  • Costovertebral angle tenderness with or without symptoms of cystitis
  • Urine culture prior to starting antibiotics recommended for all patients 
  • Blood cultures may be considered in some clinical scenarios such as:
    • Diagnostic uncertainty and sepsis
    • Persistent fever or other systemic symptoms despite empiric therapy

Management & Treatment

  • Nitrofurantoin and fosfomycin should not be used for pyelonephritis because of low renal tissue concentration
  • If pregnancy, see IWK Guidance on Firstline

If requiring admission or unable to take oral therapy

  • Colonization or recent infection with resistant Gram-negative microorganisms (e.g. Pseudomonas), OR
  • Septic presentation and hospital acquired/frequent outpatient antibiotic use for urinary infections

More Information

Last Reviewed: April 2022

  1. Herness, Joel, Buttolph, Amelia, and Hammer, Noa C. Acute Pyelonephritis in Adults: Rapid Evidence Review. American Family Physician 102.3 (2020): 173-80.
  2. NICE. Pyelonephritis (acute): antimicrobial prescribing guidelines. October 31, 2018. Link.
  3. Nicole, L. Urinary tract infection. Canadian Pharmacists Association. CPS. April 12, 2021. Available with subscription. 
  4. BMJ Best Practice. Acute pyelonephritis. June 10, 2021. 
  5. Hooton TM. Clinical practice. Uncomplicated urinary tract infection. N Engl J Med. 2012 Mar 15;366(11):1028-37.
  6. Grant J, Le Saux N. Practice point: duration of antibiotic therapy for common infections. J Assoc Med Microbiol Infect Dis Can. Epub 2021 Apr 29. Link.