Common signs and symptoms include acute-onset fever, chills, severe back or flank pain, nausea and vomiting, and costovertebral angle tenderness.
Urinalysis and urine culture confirm the diagnosis of pyelonephritis. Urine cultures, obtained prior to treatment, demonstrate bacteria, most often Escherichia coli.
The route and choice of empiric antibiotics depend on the severity of illness and the presumed bacterial sensitivities pending culture results.
Complications most often result from inappropriate (wrong drug or wrong dose) antibiotic use or antibiotic resistance, leading to recurrent or progressive infection.
Other common causes of complications are inadequate treatment of anatomical abnormalities (e.g., kidney stones or obstruction), preventing bacterial clearance.
Pyelonephritis, from the Greek 'pyelo' (pelvis), 'nephros' (kidney), and '-itis' (inflammation), describes a severe infectious inflammatory disease of the renal parenchyma, calices, and pelvis that can be acute, recurrent, or chronic. Acute infections may be caused by enteric bacteria (e.g., Escherichia coli) that ascend from the lower urinary tract or that spread haematogenously to the kidney. Most episodes are uncomplicated and are cured with no residual renal damage. Complicated infections can result from underlying medical problems (e.g., diabetes mellitus, HIV), genitourinary anatomical abnormalities, obstruction (e.g., benign prostatic hypertrophy, calculi), and/or multi-drug-resistant pathogens. Urinary tract infection, or UTI, is a non-specific term that refers to infection anywhere in the urinary tract, from the urethra to the bladder to the ureters to the kidneys. Pyelonephritis refers specifically to infections in the kidney.
Urinary tract infections in children is a specialised topic that is not covered here; please see the BMJ Best Practice topic: Urinary tract infections in children.
History and exam
- urinary tract infection
- diabetes mellitus
- stress incontinence
- foreign body in urinary tract (e.g., calculus, catheter)
- anatomical/functional urinary abnormality
- immunosuppressive state (e.g., HIV, transplantation, chemotherapy, corticosteroid use)
- frequent sexual intercourse
- mother with urinary tract infection history
- new sex partner
- spermicide use
- age between 18 and 50 years
- age >60 years
Professor of Medicine
Division of Nephrology
University of California
LAF declares that she has no competing interests.
Dr Lynda A. Frassetto would like to gratefully acknowledge the assistance of Donna M. Frassetto. DMF declares that she has no competing interests.
Providence Saint Joseph Medical Center
Assistant Clinical Professor of Urology
Department of Urology
David Geffen School of Medicine at UCLA
JL declares that he has no competing interests.
Consultant Nephrologist/Lead Clinician
Glasgow Royal Infirmary
NHS Greater Glasgow and Clyde
RM declares that he has no competing interests.
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