• Etiology
  • Congenital
    • Intrinsic: malformation of the smooth muscle of a ureteral segment and consecutive impairment of peristalsis (functional stenosis)
    • Extrinsic: aberrant renal pole artery causing proximal ureteral obstruction
  • Acquired: factors causing ureteral obstruction
• Clinical features
  • Newborns and infants
    • Palpable upper abdominal mass
    • Failure to thrive
    • Recurrent pyelonephritis
  • Children and adults
    • Flank pain or upper abdominal pain that may be triggered or worsened during states of increased diuresis (e.g., after caffeine or alcohol consumption).
    • Nausea/vomiting
    • Recurrent pyelonephritis
    • Hematuria
• Diagnostics
  • Ultrasound
    • In industrialized countries, most cases of congenital ureteropelvic junction obstruction are diagnosed antenatally with hydronephrosis on prenatal ultrasound.
  • IV urography
• Treatment
  • Observation: asymptomatic, mild cases
  • Surgery
    • Symptomatic patients or those with > 40% loss of renal function