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[edit] Discussion of Megaureter

  • Megaureter is a generic term indicating the presence of an enlarged ureter with or without concomitant dilatation of the upper collecting system.
  • Primary megaureter is a term that includes all cases of megaureter due to an idiopathic congenital alteration at the vesicoureteral junction.
  • There are three major categories of primary megaureter:
    • Obstructed primary megaureter: Dilatation above a short, aperistaltic, normal-caliber juxtavesical section of a normally inserted ureter. Somewhat similar to achalasia and Hirschsprung disease.
    • Refluxing primary megaureter: Caused by a short or absent intravesical ureter, congenital paraureteric diverticulum, or other derangement of the vesicoureteral junction
    • Nonrefluxing unobstructed primary megaureter: Ureter is dilated beginning at a point just above the bladder. The cause of this phenomenon is unknown.

  • Primary nature of megaureter must be confirmed by excluding secondary causes such as posterior urethral valves or neuropathic bladder.
  • In obstructed primary megaureter, VCUG demonstrates no vesicoureteral reflux. US shows hydronephrosis and ureteral dilatation above the persistently narrowed distal aperistaltic segment.
  • In primary megaureter, once VUR has been excluded, perfusion studies and diuresis renography are indicated to differentiate dilatation that is functionally obstructive and requires surgical treatment from dilatation that represents a variant in normal ureteral development and can be conservatively treated initially.

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Patient #1

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[edit] References for Megaureter