Editing Pediatrics: Anomalies of the Kidneys (section)

== Anomalies of Ascent ==

* '''Simple Renal Ectopia'''
** More commonly diagnosed in females because they are more apt to undergo uroradiologic evaluation for urinary tract infection (UTI) and/or associated genital anomalies
** The left side is affected slightly more than the right.
** '''An ectopic kidney can be found in one of the following positions (5):'''
**# '''Pelvic (most common site)'''
**#* Estimated to occur in 1 of 2100 to 3000 autopsies
**# '''Iliac'''
**# '''Abdominal'''
**# '''Thoracic'''
**# '''Contralateral or crossed'''
** '''Embryology'''
*** '''The UB, arising from the WD at the end of the 4th week, grows cranial toward the urogenital ridge, acquiring a cap of metanephric blastema by the 5th week. The developing metanephric tissue and UB migrate cephalad. The entire process is completed by 8 weeks’ gestation.'''
*** Factors that may prevent the orderly ascent and rotation of the kidneys include UB maldevelopment, defective metanephric tissue that fails to induce ascent, genetic abnormalities, and maternal illnesses or teratogenic causes
** '''Description and Associated Anomalies'''
*** '''The renal pelvis is usually anterior''' (instead of medial);
**** As a result, 56% of ectopic kidneys have a '''hydronephrotic collecting system'''.
***** '''Of those with hydronephrosis:'''
****** 50% from '''obstruction of the ureteropelvic''' or the ureterovesical junction (70% and 30%, respectively)
****** 25% from reflux grade III or greater
****** 25% from the malrotation alone
*** Vesicoureteral reflux has been found in 30% of children with ectopic kidneys.
*** The incidence of genital anomalies in the patient with ectopia is about 15%.
*** '''The ureteric orifice is positioned normally''', except for those unusual cases with ectopic ureters
*** In females, 20-66% have ≥1 of the following abnormalities of the reproductive organs:
***# Bicornuate or unicornuate uterus with atresia of one horn
***# Rudimentary or absent uterus and proximal and/or distal vagina
***# Duplication of the vagina
*** In males, 10-20% have a recognizable associated genital defect; undescended testes, duplication of the urethra, and hypospadias are the most common
** '''Diagnosis'''
*** '''Most ectopic kidneys are clinically asymptomatic, except in cases of associated ectopic ureter.'''
**** Thoracic kidneys are also usually asymptomatic
** Prognosis
*** The ectopic kidney is no more susceptible to disease than the orthotopic kidney, except for the development of hydronephrosis or stones. This may be a result of the anteriorly placed pelvis and malrotation of the kidney, which may impair drainage of urine from a high insertion of the ureter to the pelvis or anomalous vasculature that partially obstructs one of the major calyces or the upper ureter.
*** May be an increased risk of injury from blunt abdominal trauma, because the low-lying kidney is not protected by the rib cage.