- A syndrome caused by infection of the renal parenchyma and/or renal pelvis, often producing localized flank/back pain combined with systemic symptoms, such as fever, chills, nausea and vomiting; there is a wide spectrum of illness ranging from mild symptoms to septic shock.
- Chronic pyelonephritis is the result of progressive inflammation of the renal interstitium and tubules, due to recurrent infection, vesicoureteral reflux, or both.
- Pyelonephritis is considered uncomplicated if the infection is caused by a typical pathogen in an immunocompetent patient with normal urinary tract anatomy and renal function.
- System(s) affected: renal; urologic
- Synonym: acute upper urinary tract infection (UTI)
- May present as altered mental status; absence of fever is common in the elderly.
- Older patients with diabetes and pyelonephritis are at higher risk for bacteremia, prolonged hospitalization, and mortality.
- The high prevalence of asymptomatic bacteriuria in the elderly makes the use of urine dipstick less reliable for diagnosing UTI in this population.
- Most common medical complication requiring hospitalization. Pregnant women with asymptomatic bacteriuria (ABU) have 20–30% risk to develop acute pyelonephritis if ABU is not treated.
- Affects 1–2% of all pregnancies. Morbidity does not differ between trimesters.
- Urine culture for test of cure 1 to 2 weeks after therapy.
- Consider low-dose suppressive antibiotics for the remainder of pregnancy following treatment for pyelonephritis or recurrent cystitis in pregnancy.
- UTI is present in ~5% of patients age 2 months to 2 years with fever and no apparent source on history and physical exam.
- Treatment (PO or IV; inpatient or outpatient) should be based on the clinical situation and patient toxicity.
Community-acquired acute pyelonephritis: 3 to 4 cases per 10,000 males; 15 to 17 cases per 10,000 females; 28 cases per 10,000 women ages 18 to 49 years.
Adult cases: 250,000/year, with 200,000 hospitalizations
Etiology and Pathophysiology
- Escherichia coli (>80%)
- Other gram-negative pathogens: Proteus, Klebsiella, Serratia, Clostridium, Pseudomonas, and Enterobacter spp.
- Enterococcus spp.
- Staphylococcus: Staphylococcus epidermidis, Staphylococcus saprophyticus (number 2 cause in young women), and Staphylococcus aureus
- Candida spp.
- Underlying urinary tract abnormalities
- Indwelling catheter/recent urinary tract instrumentation
- Immunocompromised, including diabetes
- Elderly, institutionalized patients (particularly women)
- Prostatic enlargement, stress incontinence
- Childhood UTI
- Acute pyelonephritis within the prior year
- Recent sexual intercourse; spermicide use; new sex partner within the prior year
- Hospital-acquired infection
- Symptoms >7 days at time of presentation
Commonly Associated Conditions
- Indwelling catheters, renal calculi
- Benign prostatic hyperplasia
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Domino, Frank J., et al., editors. "Pyelonephritis." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116507/all/Pyelonephritis.
Pyelonephritis. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116507/all/Pyelonephritis. Accessed June 10, 2023.
Pyelonephritis. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116507/all/Pyelonephritis
Pyelonephritis [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 June 10]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116507/all/Pyelonephritis.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Pyelonephritis ID - 116507 ED - Domino,Frank J, ED - Baldor,Robert A, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116507/all/Pyelonephritis PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -