Diagnosis
Pyonephrosis
A complication of pyelonephritis with the combination of obstruction (hydronephrosis) and bacterial infection resulting in the presence of pus in the renal pelvis [snu][ayq].
Etiology
Cause
Urolithiasis
Fungus balls
Cancer (renal, testicular, colon, urothel)
Pregnancy
Ureteropelvic junction obstruction
Ureterovesical junction obstruction
Neurogenic bladder
Ureteral stricture
Microbe: Escherichia coli, Enterococcus, Enterobacter, Klebsiella, Proteus, Pseudomonas, Bacteroides, Staphylococcus, Salmonella, Tuberculosis, Candida/Fungus
Pathophysiology [stn]
Urinary tract obstruction --> hydronephrosis --> pyelonephritis --> pus formation in the collecting system = pyonephrosis
If not treated promptly, this infectious process may progress to urosepsis
Risk factor [ayq]
Immunosupporesion (steroids, diabetes mellitus, HIV/AIDS)
Obstruction (stones, tumors, ureteropelvic junction obstruction, pelvic kidney, horseshoe kidney)
Complications
Renal failure
Sepsis
Epidemiology
Incidence per 100.000 [mc8][snu][ssk]
Symptoms & findings
Symptoms
Chills, Dysuria, Fever, Hematuria, Nausea, Pyuria, Vomiting
Clinical findings
Elevated Creatinine, Elevated CRP, Leukocytosis
Anamneses
None listed.
Localized findings
Approach
Blood test
Blood culture
Urine stix
Urine culture
Ultrasound abdomen
CT abdomen [vb1]
MRI
Antegrade nephrostography
Biopsy
Treatment
Antibiotic therapy: Broad-spectrum to prevent sepsis [ayq][atw][ssk][ksa]
IV fluids
Drainage of the infected collecting system is essential (a surgical emergency)
Percutaneous nephrostomy is preferable in patients with sepsis
Ureteral double-J stent in patients who are not septic (manipulation may induce sepsis and toxemia)
Additional imaging evaluation to identify the cause of the urinary obstruction
Treatment of the underlying condition
Nephrectomy
Differential diagnoses
Appendicitis, Bladder cancer, Cervicitis, Chlamydia, Discitis, Endometritis, Glomerulonephritis, Herpes simplex, Hydronephrosis, Interstitial cystitis, Ovarian abscess, Pelvic inflammatory disease, Perforated ulcer, Prostatitis, Pyelonephritis, Ruptured ovarian cyst, Urinary tract infection, Urolithiasis, Vaginitis, Wilms Tumor, Xanthogranulomatous pyelonephritis
References
[1] Kumar LP, Khan I, Kishore A, Gopal M, Behera V. Pyonephrosis among Patients with Pyelonephritis Admitted in Department of Nephrology and Urology of a Tertiary Care Centre: A Descriptive Cross-sectional Study. JNMA J Nepal Med Assoc. 2023 Feb 1;61(258):111-114.
[2] http://emedicine.medscape.com/article/440548 (2014-01-02); [Medscape]
[3] Sabih A, Leslie SW. Complicated Urinary Tract Infections. [Updated 2024 Dec 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK436013/
[4] Watt I, Roylance J. Pyonephrosis. Clin Radiol. 1976 Oct;27(4):513-19.
[5] Abderrahmane D, et al. (2024). Managing of Pyonephrosis: About 42 Cases. Mathews J Urol Nephrol. 6(2):21.
[6] Zulfiqar M, Ubilla CV, Nicola R, Menias CO. Imaging of Renal Infections and Inflammatory Disease. Radiol Clin North Am. 2020 Sep;58(5):909-923.
[7] NS Ndour, CZ Ondo, A Sarr, A Ndiath, M Ndiaye, A Athie, O Sow, M Diaw, A Thiam, B Sine, B Diao, and AK Ndoye. Pyonephrosis: epidemiological, clinical, and therapeutic aspects at Aristide Le Dantec University Hospital Centre (Dakar). African Urology 2024;4:7-11.
[8] Kbirou A., Elafifi M., Moataz A., Dakir M., Debbagh A., Aboutaieb R. Evolutionary profile of pyonephrosis after surgical treatment, about 23 cases. International Journal of Surgery Open, volume 40, pages 100448.