Editing Pediatrics: Anomalies of the Kidneys (section)

== Anomalies of Renal Vasculature ==

=== Aberrant, Accessory, or Multiple Vessels ===
* The correct term to describe any kidney supplied by >1 vessel is '''multiple renal arteries.'''
* The terms '''anomalous vessels or aberrant vessels''' should be reserved for those arteries that originate from vessels other than the aorta or main renal artery.
* The term '''accessory vessels''' denotes ≥2 arterial branches supplying the same renal segment.
* Polar arteries or multiple renal arteries to the normally positioned kidney represent a failure of complete degeneration of all primitive vascular channels.
* Description
** Based on vascular supply, the renal parenchyma is divided into 5 segments:
**# Apical
**# Upper
**# Middle
**# Lower
**# Posterior
*** The main renal artery divides initially into an anterior and posterior branch.
**** The anterior branch almost always supplies the upper, middle, and lower segments of the kidney.
**** The posterior branch invariably supplies the posterior and lower segments.
**** '''The vessel to the apical segment has the greatest variation in origin'''
***** Arises from:
****** Anterior division (43%)
****** Junction of the anterior and posterior divisions (23%)
****** Main-stem renal artery or aorta (23%)
****** Posterior division of the main renal artery (10%).

=== Renal Artery Aneurysm (RAAs) ===
* Overall incidence 0.1-0.3%
* '''Classified: saccular, fusiform, dissecting, and arteriovenous'''
** '''The saccular aneurysm,''' a localized outpouching that communicates with the arterial lumen by a narrow or wide opening, '''is the most common type'''
** When the aneurysm is '''located at the bifurcation of the main renal artery and its anterior and posterior divisions''', or at one of the more distal branchings, it is considered to be congenital in origin and is called the '''fusiform type'''
* Diagnosis and Evaluation
** History and Physical Exam
*** History
**** Most RAAs are silent, especially in children.
**** Many asymptomatic RAAs are diagnosed during an evaluation of hypertension
*** Physical Exam
**** Diagnosis is suspected when a pulsatile mass is palpated in the region of the renal hilum or when a bruit is heard on abdominal auscultation
** Imaging
*** A wreathlike calcification in the area of the renal artery or its branches (30%) is highly suggestive.
* '''Management'''
** '''Indications for intervention (7):'''
**# '''Rapidly expanding'''
**# '''Female and considering pregnancy''' (rupture during pregnancy is a likely possibility)
**# '''Renal artery aneurysm > 2.0cm''' (some sources say >2.5cm)
**# '''Symptoms (uncontrolled hypertension from renal artery stenosis, flank pain, hematuria)'''
**# '''Renal ischemia/infarction (resulting from embolization from the aneurysm)'''
**# '''Incomplete ringlike calcification is present'''
**# '''Arteriovenous fistula is present'''
** '''Options: endovascular vs. surgical repair'''
*** '''In young patients, surgical repair may be preferred as endovascular stent may require lifelong anti-coagulation'''

=== Renal Arteriovenous Fistula ===
* Classified: congenital vs. acquired
** Congenital
*** <25% of all renal arteriovenous fistulas (AVFs) are congenital.
*** They are identifiable by their cirsoid configuration and multiple communications between the main or segmental renal arteries and venous channels.
*** Although congenital, they rarely present clinically before the third or fourth decade.
*** Females are affected three times as often as males
*** Right kidney is involved slightly more often than the left.
*** The lesion is usually located in the upper pole (45% of cases), but not infrequently it may be found in the mid-portion (30%) or in the lower pole (25%) of the kidney.
** Acquired
*** Results from a congenital aneurysm eroding into an adjacent vein
* Often requires surgical intervention