Ureteropelvic Junction Obstruction

Excerpt

The kidneys have many important functions in the human body. They are the major organs for maintaining fluid and electrolyte balance. They do not only share a great role in acid-base balance in the body, but they also have a vital role in controlling blood pressure and erythropoietin secretions.

During fetal life, the kidneys develop from the metanephric mesoderm up to the distal tubules. The collecting duct, major and minor calyces, renal pelvis, and ureters arise from the ureteric bud, which originates from the mesonephric duct during the fifth week of the intrauterine phase. This explains that the ureteropelvic junction (UPJ) is wholly made by the ureteric bud rather than the fusion of two different mesenchymal tissues.

Ureteropelvic junction obstruction (UPJO) is a well-recognized clinical entity that results in impaired urine flow from the renal pelvis into the ureter and, if not detected and treated properly, can result in complete loss of the affected kidney. UPJO is mainly a congenital condition that can be detected by antenatal ultrasound during the second trimester.