Editing Pyelonephritis (section)

==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/>