View source for Hydronephrosis

{{Infobox_Disease |
  Name           = {{PAGENAME}} |
  Image          = Hydro.jpg|
  Caption        = Ultrasound picture of hydronephrosis caused by a left ureteral stone|
  DiseasesDB     = 6145 |
  ICD10          = {{ICD10|N|13|0|n|10}}-{{ICD10|N|13|3|n|10}} |
  ICD9           = {{ICD9|591}} |
  ICDO           = |
  OMIM           = |
  MedlinePlus    = |
  eMedicineSubj  = |
  eMedicineTopic = |
  MeshID         = D006869 |
}}
{{Search infobox}}
{{SCC}}

'''Contributors:'''  [[User:zorkun|Cafer Zorkun]] M.D., PhD.

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==Overview==

'''Hydronephrosis''' is distention and [[dilation]] of the [[renal pelvis]], usually caused by [[obstruction]] of the free flow of [[urine]] from the [[kidney]].<ref name=robbins7>{{Cite book | author=Kumar, Vinay; Fausto, Nelson; Fausto, Nelso; Robbins, Stanley L.; Abbas, Abul K.; Cotran, Ramzi S. | authorlink= | title=Robbins and Cotran Pathologic Basis of Disease | date=2005 | edition=7th| publisher=Elsevier Saunders | location=Philadelphia, Pa. | isbn=0-7216-0187-1 | pages=1012–1014}}</ref>

==Etiology==

The obstruction may be either partial or complete and can occur anywhere from the [[urinary meatus|urethral meatus]] to the  [[Minor calyx| calyces]] of the [[renal pelvis]]. 

The obstruction may arise from either inside or outside the [[urinary tract]] or may come from the wall of the urinary tract itself. Intrinsic obstructions (those that occur within the tract) include blood clots, stones, sloughed papilla along with tumours of the kidney, ureter and bladder. Extrinsic obstructions (those that are caused by factors outside of the urinary tract) include pelvic or abdominal tumours or masses, retroperitoneal fibrosis or [[neurological]] deficits. Strictures of the ureters (congenital or acquired), neuromuscular dysfunctions or schistosomiasis are other causes which originate from the wall of the urinary tract.

==Signs and symptoms==

The signs and symptoms of hydronephrosis depends upon whether the obstruction is acute or chronic. [[Unilateral]] hydronephrosis may even occur without symptoms.<ref name=robbins7 />

Blood tests can show  raised [[creatinine]] and [[electrolyte]] imbalance. [[Urinalysis]] may show an elevated pH due to the [[secondary]] destruction of [[nephron]]s within the affected [[kidney]].

Symptoms that occur regardless of where the obstruction lies include [[loin]] or [[flank]] [[Pain and nociception|pain]]. An enlarged [[kidney]] may be [[palpable]] on [[examination]].

Where the obstruction occurs in the lower urinary tract, suprapubic tenderness (with or without a history of [[Urinary bladder|bladder]] outflow obstruction) along with a [[palpable]] bladder are strongly suggestive of [[Acute (medical)|acute]] [[urine|urinary]] [[retention]], which left untreated is highly likely to cause hydronephrosis.

Upper urinary tract obstruction is characterised by pain in the [[flank]], often radiating to either the [[abdomen]] or the [[groin]]. Where the obstruction is [[chronic (medicine)|chronic]], [[renal failure]] may also be present. If the obstruction is complete, an enlarged kidney is often [[palpable]] on examination.

==Diagnosis==

Prenatal diagnosis is possible.<ref name="pmid18520762">{{cite journal |author=Estrada CR |title=Prenatal hydronephrosis: early evaluation |journal=Curr Opin Urol |volume=18 |issue=4 |pages=401–3 |year=2008 |month=July |pmid=18520762 |doi=10.1097/MOU.0b013e328302edfe |url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?an=00042307-200807000-00012}}</ref>

Blood (U&E, [[creatinine]]) and urine (MSU, pH) tests should be taken. IVUs, ultrasounds, CTs and MRIs are also important tests. 

Ultrasound allows for visualization of the ureters and kidneys and can be used to assess the presence of hydronephrosis and/or hydroureter. 

An IVU is useful for assessing the position of the obstruction. Antegrade or retrograde pyelography will show similar findings to an IVU but offer a therapeutic option as well.

The choice of imaging depends on the clinical presentation (history, symptoms and examination findings):  

In the case of renal colic (one sided loin pain usually accompanied by a trace of blood in the urine) the initial investigation is usually an intravenous urogram. This has the advantage of showing whether there is any obstruction of flow of urine causing hydronephrosis as well as demonstrating the function of the other kidney. Many stones are not visible on plain xray or IVU but 99% of stones are visible on CT and therefore CT is becoming a common choice of initial investigation. 

MRI is less commonly used, often when there is a reason to avoid radiation exposure, e.g. in pregnancy.

'''Patient #1: CT images demonstrate marked left hydronephrosis secondary to a calculus in the proximal right ureter'''

[http://www.radswiki.net Images courtesy of RadsWiki]

<gallery>
Image:Hydronephrosis 001.jpg
Image:Hydronephrosis 003.jpg
</gallery>

===Ultrasonography===

<gallery>
Image:Hydro.jpg|Ultrasound picture of hydronephrosis caused by a left ureteral stone
</gallery>

===Histopathological Findings===

<gallery>
Image:Hydronephrosis.jpg|Specimen of a kidney that has undergone extensive dilation due to hydronephrosis. Note the extensive atrophy and thinning of the renal cortex.
</gallery>

==Treatment==
Treatment of hydronephrosis focuses upon the removal of the obstruction and drainage of the urine that has accumulated behind the obstruction. Therefore, the specific treatment depends upon where the obstruction lies, and whether it is acute or [[chronic (medicine)|chronic]].

Acute obstruction of the upper urinary tract is usually treated by the insertion of a [[nephrostomy]] tube. Chronic upper urinary tract obstruction is treated by the insertion of a [[ureteric stent]] or a [[pyeloplasty]].

Lower urinary tract obstruction (such as that caused by bladder outflow obstruction secondary to prostatic hypertrophy) is usually treated by insertion of a [[urinary catheter]] or a [[suprapubic catheter]].

Surgery is not required in all cases.<ref name="pmid18947797">{{cite journal |author=Onen A |title=Treatment and outcome of prenatally detected newborn hydronephrosis |journal=J Pediatr Urol |volume=3 |issue=6 |pages=469–76 |year=2007 |month=December |pmid=18947797 |doi=10.1016/j.jpurol.2007.05.002 |url=}}</ref>

==Complications==

Left untreated, [[bilateral]] obstruction (obstruction occurring to both [[kidney]]s rather than one) has a poor prognosis.

==References==
{{reflist|2}}

==External Links==

* [http://goldminer.arrs.org/search.php?query=Hydronephrosis Goldminer: Hydronephrosis]
* [http://www.hydronephrosis.info Hydronephrosis symptoms, diagnosis, treatment and general information]

==See also==
*[[Urology]] 
*[[Urinary tract]]

{{Nephrology}}
{{SIB}}

[[Category:Urology]]
[[Category:Nephrology]]

[[de:Hydronephrose]]
[[et:Hüdronefroos]]
[[es:Hidronefrosis]]
[[ja:水腎症]]
[[pl:Wodonercze]]
[[pt:Hidronefrose]]
[[sv:Hydronefros]]
[[zh:腎積水]]

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