View source for Pyelonephritis

{{Short description|Inflammation of the kidney}}
{{Use dmy dates|date=July 2024}}
{{cs1 config |name-list-style=vanc |display-authors=6}}
{{Infobox medical condition (new)
| name = Pyelonephritis
| synonyms = Kidney infection<ref name=NIH2017/>
| image = Xanthogranulomatous_pyelonephritis_cd68.jpg
| alt = A color photomicrograph, demonstrating macrophages and giant cells in a case of xanthogranulomatous pyelonephritis.
| caption = [[CD68]] [[immunostaining]] on this [[Micrograph|photomicrograph]] shows [[macrophage]]s and [[giant cell]]s in a case of xanthogranulomatous pyelonephritis.
| field = [[Infectious disease (medical specialty)|Infectious disease]], [[urology]], [[nephrology]]
| pronounce = {{IPAc-en|p|aɪ|ə|l|oʊ|n|ə|ˈ|f|r|aɪ|t|ɪ|s}}
| symptoms = [[Fever]], [[costovertebral angle tenderness|flank tenderness]], [[nausea]], [[dysuria|burning with urination]], [[frequent urination]]<ref name=AFP2011/>
| complications = 
| onset = 
| duration = 
| types = 
| causes = [[Bacterial infection]]<ref name=AFP2011/>
| risks = [[Sexual intercourse]], prior [[urinary tract infections]], [[diabetes]], structural problems of the [[urinary tract]], [[spermicide]] use<ref name=AFP2011/><ref name=Lip2011/>
| diagnosis = Based on symptoms and supported by [[urinalysis]]<ref name=AFP2011/>
| differential = [[Endometriosis]], [[pelvic inflammatory disease]], [[kidney stones]]<ref name=AFP2011/>
| prevention = Urination after sex, drinking sufficient fluids<ref name=NIH2017/>
| treatment = 
| medication = Antibiotics ([[ciprofloxacin]], [[ceftriaxone]])<ref name=Pre2014/>
| prognosis = 
| frequency = Common<ref name=Fer2018/>
| deaths = 
}}
<!-- Definition and symptoms -->
'''Pyelonephritis'''  is inflammation of the [[kidney]], typically due to a [[bacterial infection]].<ref name=Lip2011>{{cite book|title=Lippincott's Guide to Infectious Diseases|date=2011|publisher=Lippincott Williams & Wilkins|isbn=9781605479750|page=258|url=https://books.google.com/books?id=ZF-eoG18XXAC&pg=PA258|language=en|url-status=live|archive-url=https://web.archive.org/web/20171105194328/https://books.google.ca/books?id=ZF-eoG18XXAC&pg=PA258|archive-date=5 November 2017}}</ref> Symptoms most often include [[fever]] and [[costovertebral angle tenderness|flank tenderness]].<ref name=AFP2011/> Other symptoms may include [[nausea]], [[dysuria|burning with urination]], and [[polyuria|frequent urination]].<ref name=AFP2011/> Complications may include [[pyonephrosis|pus around the kidney]], [[sepsis]], or [[acute kidney injury|kidney failure]].<ref name=Lip2011/>

<!-- Cause and diagnosis -->
It is typically due to a bacterial infection, most commonly ''[[Escherichia coli]]''.<ref name=AFP2011/> Risk factors include [[sexual intercourse]], prior [[urinary tract infections]], [[diabetes]], structural problems of the [[urinary tract]], and [[spermicide]] use.<ref name=AFP2011/><ref name=Lip2011/> The mechanism of infection is usually spread up the [[Urinary system|urinary tract]].<ref name=AFP2011/> Less often infection occurs through the bloodstream.<ref name=NIH2017>{{cite web|title=Kidney Infection (Pyelonephritis)|url=https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-infection-pyelonephritis/all-content|website=NIDDK|access-date=30 October 2017|date=April 2017|url-status=live|archive-url=https://web.archive.org/web/20171004230310/https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-infection-pyelonephritis/all-content|archive-date=4 October 2017}}</ref> Diagnosis is typically based on symptoms and supported by [[urinalysis]].<ref name=AFP2011/> If there is no improvement with treatment, [[medical imaging]] may be recommended.<ref name=AFP2011/>

<!-- Prevention and treatment -->
Pyelonephritis may be preventable by urination after sex and drinking sufficient fluids.<ref name=NIH2017/> Once present it is generally treated with [[Antibacterial|antibiotics]], such as [[ciprofloxacin]] or [[ceftriaxone]].<ref name=Pre2014>{{cite journal | vauthors =  | title = Antibiotic therapy for acute uncomplicated pyelonephritis in women. Take resistance into account | journal = Prescrire International | volume = 23 | issue = 155 | pages = 296–300 | date = December 2014 | pmid = 25629148 }}</ref><ref>{{cite journal | vauthors = Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG, Moran GJ, Nicolle LE, Raz R, Schaeffer AJ, Soper DE | title = 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 | journal = Clinical Infectious Diseases | volume = 52 | issue = 5 | pages = e103–e120 | date = March 2011 | pmid = 21292654 | doi = 10.1093/cid/ciq257 | doi-access = free | title-link = doi }}</ref> Those with severe disease may require treatment in hospital.<ref name=AFP2011/> In those with certain structural problems of the urinary tract or [[kidney stones]], surgery may be required.<ref name=NIH2017/><ref name=Lip2011/>

<!-- Epidemiology -->
Pyelonephritis affects about 1 to 2 per 1,000 women each year and just under 0.5 per 1,000 males.<ref name=Fer2018>{{cite book| vauthors = Ferri FF |title=Ferri's Clinical Advisor 2018 E-Book: 5 Books in 1|date=2017|publisher=Elsevier Health Sciences|isbn=9780323529570|page=1097|url=https://books.google.com/books?id=wGclDwAAQBAJ&pg=PA1097|language=en|url-status=live|archive-url=https://web.archive.org/web/20171105194328/https://books.google.ca/books?id=wGclDwAAQBAJ&pg=PA1097|archive-date=5 November 2017}}</ref><ref>{{cite book| vauthors = Lager DJ, Abrahams N |title=Practical Renal Pathology, A Diagnostic Approach E-Book: A Volume in the Pattern Recognition Series|date=2012|publisher=Elsevier Health Sciences|isbn=978-1455737864|page=139|url=https://books.google.com/books?id=Ir5JIOjBCuQC&pg=PA139|language=en|url-status=live|archive-url=https://web.archive.org/web/20171105194328/https://books.google.ca/books?id=Ir5JIOjBCuQC&pg=PA139|archive-date=5 November 2017}}</ref> Young adult females are most often affected, followed by the very young and old.<ref name=AFP2011>{{cite journal | vauthors = Colgan R, Williams M, Johnson JR | title = Diagnosis and treatment of acute pyelonephritis in women | journal = American Family Physician | volume = 84 | issue = 5 | pages = 519–526 | date = September 2011 | pmid = 21888302 }}</ref> With treatment, outcomes are generally good in young adults.<ref name=Lip2011/><ref name=Fer2018/> Among people over the age of 65 the risk of death is about 40%, though this depends on the health of the elderly person, the precise organism involved, and how quickly they can get care through a provider or in hospital.<ref name=Fer2018/>
{{TOC limit|3}}

==Signs and symptoms==
[[File:Pos-renal.png|thumb|upright=1.2|Diagram showing the typical location of pain<ref>{{cite web |title=Urinary Tract Infection Common Clinical and Laboratory Features of Acute Pyelonephritis |url=https://netterimages.com/common-clinical-and-laboratory-features-of-acute-pyelonephritis-labeled-smith-1e-gynecology-frank-h-netter-10773.html |website=netterimages.com |access-date=14 July 2019}}</ref>]]
Signs and symptoms of acute pyelonephritis generally develop rapidly over a few hours or a day. It can cause high fever, [[Dysuria|pain on passing urine]], and abdominal pain that radiates along the flank towards the back. There is often associated [[vomiting]].<ref name=Ramakrishnan2005>{{cite journal | vauthors = Ramakrishnan K, Scheid DC | title = Diagnosis and management of acute pyelonephritis in adults | journal = American Family Physician | volume = 71 | issue = 5 | pages = 933–942 | date = March 2005 | pmid = 15768623 | url = http://www.aafp.org/afp/2005/0301/p933.html | url-status = live | archive-url = https://web.archive.org/web/20130514000413/http://www.aafp.org/afp/2005/0301/p933.html | archive-date = 14 May 2013 }}</ref>

Chronic pyelonephritis causes persistent flank or abdominal pain, signs of infection (fever, [[Weight loss#Unintentional|unintentional weight loss]], [[malaise]], [[Anorexia (symptom)|decreased appetite]]), [[lower urinary tract symptoms]] and [[hematuria|blood in the urine]].<ref name=Korkes2008>{{cite journal | vauthors = Korkes F, Favoretto RL, Bróglio M, Silva CA, Castro MG, Perez MD | title = Xanthogranulomatous pyelonephritis: clinical experience with 41 cases | journal = Urology | volume = 71 | issue = 2 | pages = 178–180 | date = February 2008 | pmid = 18308077 | doi = 10.1016/j.urology.2007.09.026 }}</ref> Chronic pyelonephritis can in addition cause [[fever of unknown origin]]. Furthermore, inflammation-related proteins can accumulate in organs and cause the condition [[AA amyloidosis]].<ref name=Herrera2007>{{cite book| vauthors = Herrera GA, Picken MM | veditors = Jennette JC, Olson JL, Schwartz MM, Silva FG |title=Heptinstall's Pathology of the Kidney|edition=6th|volume=2|chapter=Chapter 19: Renal Diseases|pages=853–910|publisher=Lippincott Williams & Wilkins|location=Philadelphia|year=2007|isbn=978-0-7817-4750-9|chapter-url=https://books.google.com/books?id=oWymx2hp1OoC&pg=PA886|url-status=live|archive-url=https://web.archive.org/web/20130527061439/http://books.google.com/books?id=oWymx2hp1OoC&pg=PA886|archive-date=27 May 2013}}</ref>

Physical examination may reveal fever and tenderness at the costovertebral angle on the affected side.<ref name=Weiss2007>{{cite book| vauthors = Weiss M, Liapis H, Tomaszewski JE, Arend LJ | veditors = Jennette JC, Olson JL, Schwartz MM, Silva FG |title= Heptinstall's Pathology of the Kidney|edition=6th|volume=2|chapter=Chapter 22: Pyelonephritis and other infections, reflux nephropathy, hydronephrosis, and nephrolithiasis|pages=991–1082|publisher=Lippincott Williams & Wilkins|location=Philadelphia|year=2007|isbn=978-0-7817-4750-9|chapter-url=https://books.google.com/books?id=oWymx2hp1OoC&pg=PA886}}</ref>

==Causes==
Most cases of community-acquired pyelonephritis are due to bowel organisms that enter the urinary tract. Common organisms are ''[[Escherichia coli|E.&nbsp;coli]]'' (70-80%) and ''[[Enterococcus faecalis]]''. [[Nosocomial infection|Hospital-acquired infections]] may be due to [[coliform bacteria]] and enterococci, as well as other organisms uncommon in the community (e.g., ''[[Pseudomonas aeruginosa]]'' and various species of ''[[Klebsiella]]''). Most cases of pyelonephritis start off as lower urinary tract infections, mainly [[cystitis]] and [[prostatitis]].<ref name=Ramakrishnan2005/> ''E. coli'' can invade the [[facet cell|superficial umbrella cell]]s of the bladder to form intracellular bacterial communities (IBCs), which can mature into [[biofilm]]s. These biofilm-producing ''E. coli'' are resistant to antibiotic therapy and immune system responses, and present a possible explanation for recurrent urinary tract infections, including pyelonephritis.<ref name=Hultgren2011>{{cite web|last=Hultgren|first=SJ|title=Pathogenic Cascade of E. coli UTI|work=UTI Pathogenesis|publisher=Molecular Microbiology and Microbial Pathogenesis Program, Washington University|location=St. Louis, Missouri|year=2011|url=http://www.hultgrenlab.wustl.edu/pathcascade.shtml|access-date=5 June 2011|url-status=dead|archive-url=https://web.archive.org/web/20060829090655/http://www.hultgrenlab.wustl.edu/pathcascade.shtml|archive-date=29 August 2006}}</ref> Risk is increased in the following situations:<ref name=Ramakrishnan2005/><ref name=Scholes2005>{{cite journal | vauthors = Scholes D, Hooton TM, Roberts PL, Gupta K, Stapleton AE, Stamm WE | title = Risk factors associated with acute pyelonephritis in healthy women | journal = Annals of Internal Medicine | volume = 142 | issue = 1 | pages = 20–27 | date = January 2005 | pmid = 15630106 | pmc = 3722605 | doi = 10.7326/0003-4819-142-1-200501040-00008 }}</ref>
* Mechanical: any structural abnormalities in the urinary tract, [[vesicoureteral reflux]] (urine from the bladder flowing back into the [[ureter]]), [[kidney stone]]s, [[Urinary catheterization|urinary tract catheterization]], [[Ureteric stent|ureteral stents]] or drainage procedures (e.g., [[nephrostomy]]), [[pregnancy]], [[neurogenic bladder]] (e.g., due to spinal cord damage, [[spina bifida]] or [[multiple sclerosis]]) and [[prostate]] disease (e.g., [[benign prostatic hyperplasia]]) in men
* Constitutional: [[diabetes mellitus]], [[Immunodeficiency|immunocompromised]] states
* Behavioral: change in sexual partner within the last year, [[spermicide]] use
* Positive [[family history]] (close family members with frequent urinary tract infections)

==Diagnosis==

===Laboratory examination===
[[Urinalysis|Analysis of the urine]] may show signs of urinary tract infection. Specifically, the presence of [[Nitrite test|nitrite]] and [[white blood cell]]s on a [[urine test strip]] in patients with typical symptoms are sufficient for the diagnosis of pyelonephritis, and are an indication for [[empirical treatment]]. [[Blood test]]s such as a [[complete blood count]] may show [[neutrophilia]]. [[Microbiological culture]] of the urine, with or without [[blood culture]]s and [[Kirby-Bauer antibiotic testing|antibiotic sensitivity testing]] are useful for establishing a formal diagnosis,<ref name=Ramakrishnan2005/> and are considered mandatory.<ref name=Gupta2011>{{cite journal | vauthors = Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG, Moran GJ, Nicolle LE, Raz R, Schaeffer AJ, Soper DE | title = 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 | journal = Clinical Infectious Diseases | volume = 52 | issue = 5 | pages = e103–e120 | date = March 2011 | pmid = 21292654 | doi = 10.1093/cid/ciq257 | doi-access = free | title-link = doi }}</ref>

===Imaging studies===
If a kidney stone is suspected (e.g. on the basis of characteristic [[Renal colic|colicky pain]] or the presence of a disproportionate amount of blood in the urine), a [[kidneys, ureters, and bladder x-ray]] (KUB film) may assist in identifying [[radiodensity|radioopaque]] stones.<ref name=Ramakrishnan2005/> Where available, a noncontrast [[Helical cone beam computed tomography|helical CT scan]] with 5{{nbsp}}millimeter sections is the diagnostic modality of choice in the radiographic evaluation of suspected nephrolithiasis.<ref name=Pearle2007>{{cite book| vauthors = Pearle MS, Calhoun EA, Curhan GC | veditors = Litwin MS, Saigal CS |title=Urologic Diseases in America (NIH Publication No. 07–5512)|chapter=Chapter 8: Urolithiasis|pages=283–319|publisher=US Department of Health and Human Services, Public Health Service, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases|location=Bethesda, Maryland|year=2007|chapter-url=http://kidney.niddk.nih.gov/statistics/uda/Urolithiasis-Chapter08.pdf|url-status=live|archive-url=https://web.archive.org/web/20110915045339/http://kidney.niddk.nih.gov/statistics/uda/Urolithiasis-Chapter08.pdf|archive-date=15 September 2011}}</ref><ref name=SmithCentennial2000>{{cite journal | vauthors = Smith RC, Varanelli M | title = Diagnosis and management of acute ureterolithiasis: CT is truth | journal = AJR. American Journal of Roentgenology | volume = 175 | issue = 1 | pages = 3–6 | date = July 2000 | pmid = 10882237 | doi = 10.2214/ajr.175.1.1750003 | s2cid = 73387308 }}</ref><ref name=Fang2009>{{cite book| vauthors = Fang LS | veditors = Goroll AH, Mulley AG |title=Primary care medicine: office evaluation and management of the adult patient|edition=6th|chapter=Chapter 135: Approach to the Paient with Nephrolithiasis|pages=962–7|publisher=Lippincott Williams & Wilkins|location=Philadelphia|year=2009|isbn=978-0-7817-7513-7 |chapter-url=https://books.google.com/books?id=bIZvJPcSEXMC&q=nephrolithiasis+%22physical+examination%22&pg=PA964}}</ref> All stones are detectable on CT scans except very rare stones composed of certain drug residues in the urine.<ref name=Pietrow2006>{{cite journal | vauthors = Pietrow PK, Karellas ME | title = Medical management of common urinary calculi | journal = American Family Physician | volume = 74 | issue = 1 | pages = 86–94 | date = July 2006 | pmid = 16848382 | url = http://www.aafp.org/afp/2006/0701/p86.pdf | url-status = live | archive-url = https://web.archive.org/web/20111123060406/http://www.aafp.org/afp/2006/0701/p86.pdf | archive-date = 23 November 2011 }}</ref> In patients with recurrent ascending urinary tract infections, it may be necessary to exclude an anatomical abnormality, such as vesicoureteral reflux or [[polycystic kidney disease]]. Investigations used in this setting include [[Renal ultrasonography|kidney ultrasonography]] or [[voiding cystourethrogram|voiding cystourethrography]].<ref name=Ramakrishnan2005/> CT scan or kidney ultrasonography is useful in the diagnosis of xanthogranulomatous pyelonephritis; serial imaging may be useful for differentiating this condition from kidney cancer.<ref name=Korkes2008/>

[[File:Ultrasonography of acute pyelonephritis.jpg|thumb|Acute pyelonephritis with increased cortical echogenicity and blurred delineation of the upper pole<ref name=Hansen2015>Content initially copied from: {{cite journal | vauthors = Hansen KL, Nielsen MB, Ewertsen C | title = Ultrasonography of the Kidney: A Pictorial Review | journal = Diagnostics | volume = 6 | issue = 1 | pages = 2 | date = December 2015 | pmid = 26838799 | pmc = 4808817 | doi = 10.3390/diagnostics6010002 | doi-access = free | title-link = doi }}{{Creative Commons text attribution notice|cc=by4}}</ref>]]
Ultrasound findings that indicate pyelonephritis are enlargement of the kidney, edema in the renal sinus or parenchyma, bleeding, loss of corticomedullary differentiation, abscess formation, or an areas of poor blood flow on [[doppler ultrasound]].<ref name="CraigWagner2008">{{cite journal | vauthors = Craig WD, Wagner BJ, Travis MD | title = Pyelonephritis: radiologic-pathologic review | journal = Radiographics | volume = 28 | issue = 1 | pages = 255–276 | year = 2008 | pmid = 18203942 | doi = 10.1148/rg.281075171 | doi-access = free | title-link = doi }}</ref> However, ultrasound findings are seen in only 20–24% of people with pyelonephritis.<ref name="CraigWagner2008"/>

A [[DMSA scan]] is a radionuclide scan that uses dimercaptosuccinic acid in assessing the kidney morphology. It is now{{when|date=July 2019}} the most reliable test for the diagnosis of acute pyelonephritis.<ref>{{cite journal | vauthors = Goldraich NP, Goldraich IH | title = Update on dimercaptosuccinic acid renal scanning in children with urinary tract infection | journal = Pediatric Nephrology | volume = 9 | issue = 2 | pages = 221–6; discussion 227 | date = April 1995 | pmid = 7794724 | doi = 10.1007/bf00860755 | s2cid = 34078339 }}</ref>

===Classification===

====Acute pyelonephritis====
Acute pyelonephritis is an [[exudate|exudative]] [[Pus|purulent]] localized [[inflammation]] of the [[renal pelvis]] (collecting system) and kidney. The [[Nephron|kidney parenchyma]] presents in the interstitium abscesses (suppurative [[necrosis]]), consisting in purulent exudate (pus): neutrophils, fibrin, cell debris and central germ colonies (hematoxylinophils). Tubules are damaged by exudate and may contain neutrophil casts. In the early stages, the [[glomerulus]] and vessels are normal. Gross pathology often reveals pathognomonic radiations of [[bleeding]] and [[Pus|suppuration]] through the renal pelvis to the [[renal cortex]].{{Citation needed|date=June 2011}}

====Chronic pyelonephritis====
Chronic pyelonephritis implies recurrent kidney infections and can result in [[fibrosis|scarring]] of the renal parenchyma and impaired function, especially in the setting of obstruction. A perinephric [[abscess]] (infection around the kidney) and/or [[pyonephrosis]] may develop in severe cases of pyelonephritis.<ref name=Griebling2007>{{cite book| vauthors = Griebling TL | veditors = Litwin MS, Saigal CS |title=Urologic Diseases in America (NIH Publication No. 07–5512)|chapter=Chapter 18: Urinary Tract Infection in Women|pages=589–619|publisher=US Department of Health and Human Services, Public Health Service, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases|location=Bethesda, Maryland|year=2007|chapter-url=http://kidney.niddk.nih.gov/statistics/uda/Urinary_Tract_Infection_in_Women-Chapter18.pdf|url-status=live|archive-url=https://web.archive.org/web/20110927030715/http://kidney.niddk.nih.gov/statistics/uda/Urinary_Tract_Infection_in_Women-Chapter18.pdf|archive-date=27 September 2011}}</ref>

<gallery heights="130" widths="200">
File:UOTW 72 - Ultrasound of the Week 1.webm|Abscess around both kidneys<ref name=UOTW72>{{cite web|title=UOTW #72 - Ultrasound of the Week|url=https://www.ultrasoundoftheweek.com/uotw-72/|website=Ultrasound of the Week|access-date=27 May 2017|date=11 July 2016|url-status=live|archive-url=https://web.archive.org/web/20161116142553/http://www.ultrasoundoftheweek.com/uotw-72/|archive-date=16 November 2016}}</ref>
File:UOTW 72 - Ultrasound of the Week 2.webm|Abscess around both kidneys<ref name=UOTW72/>
File:Ultrasonography of chronic pyelonephritis with reduced kidney size and focal cortical thinning.jpg|[[Chronic pyelonephritis]] with reduced kidney size and focal cortical thinning. Measurement of kidney length on the US image is illustrated by ‘+’ and a dashed line.<ref name=Hansen2015/>
</gallery>

=====Xanthogranulomatous pyelonephritis=====
[[Xanthogranulomatous inflammation|Xanthogranulomatous]] pyelonephritis is an unusual form of chronic pyelonephritis characterized by [[granuloma]]tous [[abscess]] formation, severe kidney destruction, and a clinical picture that may resemble [[renal cell carcinoma]] and other inflammatory [[nephron|kidney parenchymal]] diseases. Most affected individuals present with recurrent fevers and urosepsis, [[anemia]], and a painful kidney mass. Other common manifestations include kidney stones and loss of function of the affected kidney. Bacterial cultures of kidney tissue are almost always positive.<ref name=Malek1978>{{cite journal | vauthors = Malek RS, Elder JS | title = Xanthogranulomatous pyelonephritis: a critical analysis of 26 cases and of the literature | journal = The Journal of Urology | volume = 119 | issue = 5 | pages = 589–593 | date = May 1978 | pmid = 660725 | doi = 10.1016/s0022-5347(17)57559-x }}</ref> [[Histopathology|Microscopically]], there are granulomas and [[lipid]]-laden [[macrophage]]s (hence the term ''xantho''-, which means yellow in [[ancient Greek]]). It is found in roughly 20% of specimens from surgically managed cases of pyelonephritis.<ref name=Korkes2008/>

==Prevention==
In people who experience recurrent urinary tract infections, additional investigations may identify an underlying abnormality. Occasionally, surgical intervention is necessary to reduce the likelihood of recurrence. If no abnormality is identified, some studies suggest long-term [[Preventive medicine|preventive]] treatment with antibiotics, either daily or after [[Human sexual activity|sexual activity]].<ref name=Schooff2005>{{cite journal | vauthors = Schooff M, Hill K | title = Antibiotics for recurrent urinary tract infections | journal = American Family Physician | volume = 71 | issue = 7 | pages = 1301–1302 | date = April 2005 | pmid = 15832532 }}</ref> In children at risk for recurrent urinary tract infections, not enough studies have been performed to conclude prescription of long-term antibiotics has a net positive benefit.<ref>{{cite journal | vauthors = Williams G, Craig JC | title = Long-term antibiotics for preventing recurrent urinary tract infection in children | journal = The Cochrane Database of Systematic Reviews | volume = 4 | issue = 4 | pages = CD001534 | date = April 2019 | pmid = 30932167 | pmc = 6442022 | doi = 10.1002/14651858.CD001534.pub4 }}</ref> Cranberry products and drinking [[cranberry juice]] appears to provide a benefit in decreasing urinary tract infections for certain groups of individuals.<ref>{{cite journal | vauthors = Williams G, Stothart CI, Hahn D, Stephens JH, Craig JC, Hodson EM | title = Cranberries for preventing urinary tract infections | journal = The Cochrane Database of Systematic Reviews | volume = 2023 | issue = 11 | pages = CD001321 | date = November 2023 | pmid = 37947276 | pmc = 10636779 | doi = 10.1002/14651858.CD001321.pub7 }}</ref>

==Management==
In people suspected of having pyelonephritis, a urine culture and [[antibiotic sensitivity]] test is performed, so therapy can eventually be tailored on the basis of the infecting organism.<ref name=Fer2018/> As most cases of pyelonephritis are due to bacterial infections, antibiotics are the mainstay of treatment.<ref name=Fer2018/> The choice of antibiotic depends on the species and antibiotic sensitivity profile of the infecting organism, and may include [[Quinolone antibiotic|fluoroquinolones]], [[cephalosporin]]s, [[aminoglycoside]]s, or [[trimethoprim/sulfamethoxazole]], either alone or in combination.<ref name=Gupta2011/>

===Simple===
A 2018 systematic review recommended the use of norfloxacin as it has the lowest rate of side effects with a comparable efficacy to commonly used antibiotics.<ref name="Cattrall Robinson Kirby 2018 pp. 2285–2291">{{cite journal | vauthors = Cattrall JW, Robinson AV, Kirby A | title = A systematic review of randomised clinical trials for oral antibiotic treatment of acute pyelonephritis | journal = European Journal of Clinical Microbiology & Infectious Diseases | volume = 37 | issue = 12 | pages = 2285–2291 | date = December 2018 | pmid = 30191339 | doi = 10.1007/s10096-018-3371-y | doi-access = free | title-link = doi }}</ref>

In people who do not require hospitalization and live in an area where there is a low prevalence of [[Antibiotic resistance|antibiotic-resistant]] bacteria, a fluoroquinolone by mouth such as [[ciprofloxacin]] or [[levofloxacin]] is an appropriate initial choice for therapy.<ref name=Fer2018/> In areas where there is a higher prevalence of fluoroquinolone resistance, it is useful to initiate treatment with a single intravenous dose of a long-acting antibiotic such as [[ceftriaxone]] or an aminoglycoside, and then continuing treatment with a fluoroquinolone. Oral trimethoprim/sulfamethoxazole is an appropriate choice for therapy if the bacteria is known to be susceptible.<ref name=Fer2018/> If trimethoprim/sulfamethoxazole is used when the susceptibility is not known, it is useful to initiate treatment with a single intravenous dose of a long-acting antibiotic such as ceftriaxone or an aminoglycoside. Oral [[beta-lactam antibiotic]]s are less effective than other available agents for treatment of pyelonephritis.<ref name=Gupta2011/> Improvement is expected in 48 to 72 hours.<ref name=Fer2018/>

===Complicated===
People with acute pyelonephritis that is accompanied by high fever and [[leukocytosis]] are typically admitted to the hospital for intravenous hydration and intravenous antibiotic treatment. Treatment is typically initiated with an intravenous fluoroquinolone, an aminoglycoside, an [[extended-spectrum penicillin]] or cephalosporin, or a [[carbapenem]]. Combination antibiotic therapy is often used in such situations. The treatment regimen is selected based on local resistance data and the susceptibility profile of the specific infecting organism(s).<ref name=Gupta2011/>

During the course of antibiotic treatment, serial white blood cell count and temperature are closely monitored. Typically, the intravenous antibiotics are continued until the person has no fever for at least 24 to 48{{nbsp}}hours, then equivalent antibiotics by mouth can be given for a total of two-week duration of treatment.<ref name=Starlin2005>{{cite book|last1=Cabellon|first1=MCL|editor-last=Starlin|editor-first=R|title=The Washington Manual: Infectious Diseases Subspecialty Consult|edition=1st|chapter=Chapter 8: Urinary Tract Infections|pages=95–108|publisher=Lippincott Williams & Wilkins|location=Philadelphia|year=2005|isbn=978-0-7817-4373-0|chapter-url=https://books.google.com/books?id=DdabV2chPzMC&pg=PA105|url-status=live|archive-url=https://web.archive.org/web/20130527045956/http://books.google.com/books?id=DdabV2chPzMC&lpg=PA105|archive-date=27 May 2013}}</ref> Intravenous fluids may be administered to compensate for the reduced oral intake, insensible losses (due to the raised temperature) and [[vasodilation]] and to optimize urine output. [[Percutaneous nephrostomy]] or ureteral stent placement may be indicated to relieve obstruction caused by a stone. Children with acute pyelonephritis can be treated effectively with oral antibiotics ([[cefixime]], [[ceftibuten]] and [[Augmentin|amoxicillin/clavulanic acid]]) or with short courses (2 to 4{{nbsp}}days) of intravenous therapy followed by oral therapy.<ref name=Strohmeier2014>{{cite journal | vauthors = Strohmeier Y, Hodson EM, Willis NS, Webster AC, Craig JC | title = Antibiotics for acute pyelonephritis in children | journal = The Cochrane Database of Systematic Reviews | volume = 2014 | issue = 7 | pages = CD003772 | date = July 2014 | pmid = 25066627 | pmc = 10580126 | doi = 10.1002/14651858.CD003772.pub4 | hdl-access = free | hdl = 2123/22283 }}</ref> If intravenous therapy is chosen, single daily dosing with aminoglycosides is safe and effective.<ref name=Strohmeier2014/>

Fosfomycin can be used as an efficacious treatment for both UTIs and complicated UTIs including acute pyelonephritis. The standard regimen for complicated UTIs is an oral 3g dose administered once every 48 or 72 hours for a total of 3 doses or a 6 grams every 8 hours for 7 days to 14 days when fosfomycin is given in IV form.<ref name="Zhanel Zhanel Karlowsky 2020 pp. 1–11">{{cite journal | vauthors = Zhanel GG, Zhanel MA, Karlowsky JA | title = Oral and Intravenous Fosfomycin for the Treatment of Complicated Urinary Tract Infections | journal = The Canadian Journal of Infectious Diseases & Medical Microbiology | volume = 2020 | pages = 8513405 | date = 28 March 2020 | pmid = 32300381 | pmc = 7142339 | doi = 10.1155/2020/8513405 | doi-access = free | title-link = doi }}</ref>

Treatment of xanthogranulomatous pyelonephritis involves antibiotics as well as surgery. [[Nephrectomy|Removal of the kidney]] is the best surgical treatment in the overwhelming majority of cases, although polar resection (partial nephrectomy) has been effective for some people with localized disease.<ref name=Korkes2008/><ref name=Rosi1986>{{cite journal | vauthors = Rosi P, Selli C, Carini M, Rosi MF, Mottola A | title = Xanthogranulomatous pyelonephritis: clinical experience with 62 cases | journal = European Urology | volume = 12 | issue = 2 | pages = 96–100 | year = 1986 | pmid = 3956552 | doi = 10.1159/000472589 }}</ref> [[Watchful waiting]] with serial imaging may be appropriate in rare circumstances.<ref name=Lebret2007>{{cite journal | vauthors = Lebret T, Poulain JE, Molinie V, Herve JM, Denoux Y, Guth A, Scherrer A, Botto H | title = Percutaneous core biopsy for renal masses: indications, accuracy and results | journal = The Journal of Urology | volume = 178 | issue = 4 Pt 1 | pages = 1184–8; discussion 1188 | date = October 2007 | pmid = 17698122 | doi = 10.1016/j.juro.2007.05.155 }}</ref>

===Follow-up===
If no improvement is made in one to two days post therapy, inpatients should repeat a urine analysis and imaging. Outpatients should check again with their doctor.<ref name="Johnson Russo pp. 48–59">{{cite journal | vauthors = Johnson JR, Russo TA | title = Acute Pyelonephritis in Adults | journal = The New England Journal of Medicine | volume = 378 | issue = 1 | pages = 48–59 | date = January 2018 | pmid = 29298155 | doi = 10.1056/nejmcp1702758 | s2cid = 3919412 }}</ref>

==Epidemiology==
There are roughly 12-13 cases annually per 10,000 population in women receiving outpatient treatment and 3-4 cases requiring admission. In men, 2-3 cases per 10,000 are treated as outpatients and 1-2 cases/10,000 require admission.<ref name=Czaja2007>{{cite journal | vauthors = Czaja CA, Scholes D, Hooton TM, Stamm WE | title = Population-based epidemiologic analysis of acute pyelonephritis | journal = Clinical Infectious Diseases | volume = 45 | issue = 3 | pages = 273–280 | date = August 2007 | pmid = 17599303 | doi = 10.1086/519268 | doi-access = free | title-link = doi }}</ref> Young women are most often affected. Infants and the elderly are also at increased risk, reflecting anatomical changes and hormonal status.<ref name=Czaja2007/> Xanthogranulomatous pyelonephritis is most common in middle-aged women.<ref name=Malek1978/> It can present somewhat differently in children, in whom it may be mistaken for [[Wilms' tumor]].<ref name=Goodman1998>{{cite journal | vauthors = Goodman TR, McHugh K, Lindsell DR | title = Paediatric xanthogranulomatous pyelonephritis | journal = International Journal of Clinical Practice | volume = 52 | issue = 1 | pages = 43–45 | year = 1998 | pmid = 9536568 | doi = 10.1111/j.1742-1241.1998.tb11558.x | s2cid = 28900400 }}</ref>

==Research==

According to a 2015 meta analysis, [[vitamin A]] has been shown to alleviate renal damage and/or prevent renal scarring.<ref name="Zhang Chen Zhao 2016 pp. 373–379">{{cite journal | vauthors = Zhang GQ, Chen JL, Zhao Y | title = The effect of vitamin A on renal damage following acute pyelonephritis in children: a meta-analysis of randomized controlled trials | journal = Pediatric Nephrology | volume = 31 | issue = 3 | pages = 373–379 | date = March 2016 | pmid = 25980468 | doi = 10.1007/s00467-015-3098-2 | s2cid = 24441322 }}</ref>

==Terminology==
The term is from [[Ancient Greek language|Greek]] πύελο|ς ''pýelo|s'', "basin" + νεφρ|ός ''nepʰrós'', "[[kidney]]" + suffix ''[[-itis]]'' suggesting "[[inflammation]]".{{citation needed|date=April 2021}}

A similar term is "'''pyelitis'''", which means inflammation of the [[renal pelvis]] and [[Renal calyx|calyces]].<ref>[http://www.medilexicon.com/medicaldictionary.php?t=74268 medilexicon.com] {{webarchive|url=https://web.archive.org/web/20140106031823/http://www.medilexicon.com/medicaldictionary.php?t=74268 |date=6 January 2014 }}</ref><ref>Using Medical Terminology: A Practical Approach 2006 p.723</ref> In other words, pyelitis together with nephritis is collectively known as pyelonephritis.{{citation needed|date=April 2021}}

==Etymology==
The word '''pyelonephritis''' is formed by the [[Greek language|Greek]] roots ''pyelo-'' from '''''πύελος''''' (púelos) [[renal pelvis]] and nephro- from '''''νεφρός''''' (nephrós) [[kidney]] together with the suffix -itis from -'''''ῖτις''''' (-itis) used in [[medicine]] to indicate [[diseases]] or [[inflammation]]s.{{cn|date=April 2022}}

== References ==
{{Reflist}}

== External links ==
{{Commons category}}
{{Medical resources
| diseasesDB_mult = {{DiseasesDB2|29255}} {{DiseasesDB2|31522}}
|  ICD10           = {{ICD10|N|10||n|10}}-{{ICD10|N|12||n|10}}, {{ICD10|N|13|6|n|10}}, {{ICD10|N|20|9|n|20}}
|  ICD9            = {{ICD9|590.0}}, {{ICD9|590.1}}, {{ICD9|590.3}}, {{ICD9|590.8}}, {{ICD9|590.81}}
|  DiseasesDB      = 11052
|  MedlinePlus     = 001274
|  eMedicineSubj   = ped
|  eMedicineTopic  = 1959
|  MeshID          = D011704
}}
* [https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-infection-pyelonephritis Kidney Infection (Pyelonephritis)] at the US [[National Institute of Diabetes and Digestive and Kidney Diseases]]

{{Nephrology}}
{{Portal bar | Medicine}}
{{Authority control}}

[[Category:Articles containing video clips]]
[[Category:Inflammations]]
[[Category:Kidney diseases]]
[[Category:Nephrology]]
[[Category:Wikipedia medicine articles ready to translate]]