CONSULT ROUNDS: CAUSES OF UPJ OBSTRUCTION

Obstruction is a common cause of Acute Kidney Injury in many patients we encounter. Sometimes we see what is referred to as UPJ or Urteropelvic Junction Obstruction. Just wanted to briefly go over the causes of that entity. Adult patients with an UPJ obstruction will commonly present to medical attention due to the development of kidney stones on the affected side, infections or blood in the urine. Rarely, the patient will describe back pain whenever he/she drinks a lot of fluid. This is called "Dietl's crisis".


The most common causes are usually
Congenital
Strictures
Crossing vessel or band pressing on the UPJ
Instrinsic Stenosis
Decreased peristalsis through UPJ


Other less common causes
Renal Cyst at that location
Aortic Aneurysm
Eisonophilic ureteritis
Xanthogranalumatous Pyelonephritis
What do they mean by crossing vessel?
In adults, the obstruction of the ureter can be caused by an extra blood vessel, usually an artery that supplies the lower part of the kidney. As a person gets older, this vessel gets bigger. Since this blood vessel will usually lie over the ureter, it can cause obstruction. This is called a "crossing vessel".


http://www.ncbi.nlm.nih.gov/pubmed/19193425