Acute pyelonephritis and urosepsis

Also known as Pyelonephritis · Urosepsis · Emphysematous pyelonephritis · Pyonephrosis · Complicated urinary tract infection

Acute pyelonephritis is upper urinary tract infection (renal parenchyma + renal pelvis). Urosepsis = sepsis from a urinary source — one of the most common causes of sepsis in ICU. Pathogenesis: ascending infection from bladder (E. coli 1, ~80%; Proteus, Klebsiella, Enterococcus, Pseudomonas); haematogenous spread in immunocompromised. Risk factors: urinary obstruction (stones, BPH, tumour), diabetes, pregnancy, catheterisation, immunocompromise, female gender, vesicoureteric reflux. Presentation: fever, rigors, flank pain, costovertebral angle tenderness, dysuria, frequency, nausea/vomiting, septic shock (urosepsis). Diagnosis: urinalysis (nitrites, leucocyte esterase, WBC), urine culture greater than 10^5 CFU/mL, blood cultures, imaging (CT — exclude obstruction, abscess, emphysematous change). Treatment: source control (relieve obstruction, drain abscess, remove catheter) + antibiotics (ceftriaxone ± gentamicin severe; ciprofloxacin/co-amoxiclav uncomplicated). Emphysematous pyelonephritis (diabetic + gas): surgical emergency, mortality 20-40%.

low17 referencesUpdated 26 July 202619 min readVerification in progress

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8 MCQs

Meet the patient

A 68-year-old man with type 2 diabetes and benign prostatic hyperplasia is readmitted to ICU on day 4 after a TURP, catheterised and confused. He is febrile at 39.2 degrees, shivering, BP 78 over 45, HR 128, RR 28, capillary refill 5 seconds. Lactate is 4.8 mmol per L, creatinine 220 (baseline 90). The urine is cloudy with Gram-negative rods on stain, and bedside POCUS shows right-sided hydronephrosis with an obstructing ureteric stone — an illustrative teaching case built around the archetype urosepsis is almost always built on: a complicated urinary tract infection with parenchymatous organ involvement and an obstructed upper tract, where the complicating factor must be identified and controlled early.^[2]^[3]

This is urosepsis with septic shock in a catheterised, diabetic, post-instrumentation patient — and the stem plants the question that governs the whole topic: is there obstruction? An obstructed, infected kidney (pyonephrosis) is pus under pressure, and antibiotics cannot penetrate it. Source control — the nephrostomy or stent — is the decisive intervention, and every uroseptic patient needs the obstruction question answered within hours.^[2]^[3]

References17Show

[1]Johnson JR, Russo TA Acute Pyelonephritis in Adults N Engl J Med, 2018.PMID 29298155
[2]Wagenlehner FM, Pilatz A, Weidner W Urosepsis--from the view of the urologist Int J Antimicrob Agents, 2011.PMID 21993485
[3]Wagenlehner FM, Tandogdu Z, Bjerklund Johansen TE An update on classification and management of urosepsis Curr Opin Urol, 2017.PMID 27846034
[4]Somani BK, Nabi G, Thorpe P, et al. Is percutaneous drainage the new gold standard in the management of emphysematous pyelonephritis? Evidence from a systematic review J Urol, 2008.PMID 18353396
[5]Gupta K, Hooton TM, Naber KG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases Clin Infect Dis, 2011.PMID 21292654
[6]Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) JAMA, 2016.PMID 26903338
[7]Chen CC, Hsieh MS, Hu SY, et al. Performance of Scoring Systems in Predicting Clinical Outcomes of Patients with Emphysematous Pyelonephritis: A 14-Year Hospital-Based Study J Clin Med, 2022.PMID 36555916
[8]Tsu JH, Chan CK, Chu RW, et al. Emphysematous pyelonephritis: an 8-year retrospective review across four acute hospitals Asian J Surg, 2013.PMID 23810162
[9]Evans L, Rhodes A, Alhazzani W, et al. Surviving sepsis campaign: international guidelines for management of sepsis and septic shock 2021 Intensive Care Med, 2021.PMID 34599691
[10]Sandberg T, Skoog G, Hermansson AB, et al. Ciprofloxacin for 7 days versus 14 days in women with acute pyelonephritis: a randomised, open-label and double-blind, placebo-controlled, non-inferiority trial Lancet, 2012.PMID 22726802
[11]Huang JJ, Tseng CC Emphysematous pyelonephritis: clinicoradiological classification, management, prognosis, and pathogenesis Arch Intern Med, 2000.PMID 10737279
[12]Pearle MS, Pierce HL, Miller GL, et al. Optimal method of urgent decompression of the collecting system for obstruction and infection due to ureteral calculi J Urol, 1998.PMID 9751331
[13]Bookstaver PB, Bland CM, Griffin B, et al. A Review of Antibiotic Use in Pregnancy Pharmacotherapy, 2015.PMID 26598097
[14]Rigonalli U, Sigg S, Moos SV, et al. Prevalence and Clinical Implications of Post-obstruction Hyperdiuresis Among Patients with Urinary Retention: A Mini Review Eur Urol Open Sci, 2025.PMID 40041096
[15]Kolman KB Cystitis and Pyelonephritis: Diagnosis, Treatment, and Prevention Prim Care, 2019.PMID 31030820
[16]Warzecha D, Pietrzak B, Urban A, Wielgoś M How to avoid drug resistance during treatment and prevention of urinary tract infections Prz Menopauzalny, 2021.PMID 35069075
[17]Nicolle LE, Gupta K, Bradley SF, et al. Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America Clin Infect Dis, 2019.PMID 30895288