Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. Mauris placerat eleifend leo.



Uretero-Pelvic Junction Obstruction (UPJ)

Is the most common cause of pelvicaliectasis w/o associated ureteral dilatation. Usually diagnosed prenatally. Most common congenital obstruction of the urinary tract. 1:1000, Boys > Girls, Left > Right, may coexist w/ VUR, Uretero-Vesical Junction (UVJ) Obstruction, MCDK

Crossing vessel

Segmental lower pole renal artery or vein may cross UPJ and cause "vascular UPJO": (intermitent hydronephrosis found usually in older children)

Imaging: US, VCUG, Scintigraphy in infants


Degree of dilation

The Society for Fetal Urology - SFU - US grading system for postnatal hydronephrosis

Voiding CystoUrethroGram (VCUG)

To determine if hydronephrosis is due to UPJ obstruction or VUR or both and asses contralateral upper urinary tract because there is frequently contralateral VUR with UPJO. UPJO can also coexist w/ ipsilateral VUR as demonstrated by dilution of contrast as it enters pelvis, suggesting there was an unopacified urine before the study begun. Delayed images will show retention of contrast above UPJ.

RNS: Radionuclide Scintigraphy - 99mTc labelled Mercaptoacetyltriglycine (99mTc-MAG3) followed by Lasix. Follow pts for progression, stability or resolution of UPJO.

CT/MRI: incidental findings of pelvicaliectasis or extrarenal pelvis, not a first study to get, order, US+VCUG; good for vascular UPJO - crossing artery

TH: prophylactic abx, surgery (Hynes-Anderson pyeloplasty) or nephrectomy
Postoperative imaging: 6 wks after, US, RNS, IVU (intravenous urography)