Ch41 UPJO

• Intrinsic
• - Result of an interruption in the development of the circular musculature of the UPJ
• - Valvular mucosal folds
• - Persistent fetal convolutions
• - Upper ureteral polyps

• Extrinsic
•  - Aberrant, accessory, or early-branching lower-pole vessel is the most common cause of extrinsic UPJ obstruction

• Secondary 
• - Severe VUR- ureter elongates and develops a torturous course, a kink may develop in the UPJ area, a point of relative fixation, and may cause an obstruction secondarily

• Presence of an aperistaltic segment of the ureter - spiral musculature normally present has been replaced by abnormal longitudinal muscle bundles or fibrous tissue. 
• Decreased interstitial cells of Cajal at the UPJ in children.

Renal pelvis is continuously perfused at 10 mL/min

Renal pelvic pressure is monitored.

During the infusion, the bladder is continuously drained with an indwelling catheter to prevent transmission of intravesical pressures.

12 - 15 cm H2O - Nonobstructed system. 

>  15 - 22 cm H2O  - Obstruction

• Presence of symptoms associated with the obstruction
• Impairment of overall renal function or progressive impairment of ipsilateral function
• Development of stones or infection
• Causal hypertension