Ureters are the two tubes that transport urine from the kidneys to the bladder. A megaureter is an enlarged, swollen ureter that is about double the normal size. This condition occurs congenitally (present at birth) in about 0.4 of each 1,000 births.
The word “hydroureteronephrosis” is sometimes used describe an enlarged ureter. This is a more broad term for swelling in the urinary tract, when the underlying cause is unknown.
Megaureters are classified as either “refluxing” or “non-refluxing.”
The two most common causes are:
Other conditions can cause megaureter, including neurogenic bladder, ectopic ureter, ureteroceles, or other bladder-outlet obstructions (posterior urethral valves, urethral polyps, or Prune Belly Syndrome).
The diagnosis is usually made when the baby is still in utero, when hydroureteronephrosis is detected during a routine anatomy-scan ultrasound. Once the baby is born, testing is typically performed to confirm the diagnosis.
This type of ultrasound examination assesses the degree of swelling in the kidneys and urinary tract, and looks for any abnormalities in the bladder.
This imaging exam looks at the urinary tract to determine the cause for hydroureteronephrosis. This test may be used to rule out VUR as a cause for hydroureteronephrosis.
VCUG may be performed when babies have a prenatal diagnosis of hydroureteronephrosis (especially if the baby also has a febrile urinary tract infection), or when there is dilation of both kidneys.
If the urologist has ruled out VUR or a bladder-outlet obstruction (with RUS and VCUG procedures), this test is usually the next step.
The MAG3 Lasix Scan evaluates kidney function, including how well the kidneys drain. This test will show the percentage of how well each kidney is functioning relative to the other. Each kidney should contribute 45 percent to 55 percent of total function (totaling 100 percent of function). If one kidney functions at less than 40 percent or the function is declining by more than 5 percent, surgery is usually necessary.
Your child's treatment and management plans will depend on the underlying cause and the specific symptoms of megaureter. Most infants will need to be started on prophylactic antibiotics to prevent a urinary tract infection (UTI). For boys with megaureter, circumcision may be considered to decrease the risk of infection.
Sometimes repeat renal ultrasounds are necessary, and some cases may need surgical intervention. Surgery may be necessary if any of the following conditions exist:
Memorial Hermann Professional Building
Vanguard Urologic Institute
6400 Fannin St., Suite 2300
Houston, Texas 77030
Phone: (713) 366-7800
Fax: (713) 482-5816
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