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What is megaureter?

Megaureter means dilated ureter. It  is an abnormality of one or both of your child's ureters. Ureters are the two funnel-shaped tubes that carry urine from the kidneys to the bladder. A megaureter refers to an expanded or widened ureter that does not work normally. The width of the megaureter is usually greater than 10 millimeters (three-eighths of an inch).

Complications of megaureter include reverse flow of urine into the kidneys and pooling of urine inside the ureter that does not drain. This can cause a child to develop a urinary tract infection. In some children, complications from megaureter can cause kidney damage and failure.

What causes a megaureter?

A megaureter that is not associated with other problems occurs during fetal development. It occurs when a section of the ureter, which is normally a muscular layer of tissue, is replaced by stiff, fibrous tissue. In the absence of a muscular layer, normal peristalsis (worm-like movement of the ureter that propels urine toward the bladder) can't occur.

Megaureter can occur alone, but usually occurs along with other problems, such as prune belly syndrome.

What are the symptoms of megaureter?

The syndrome may occur in varying degrees, possibly causing blockage and reverse flow of urine. However, each child may experience symptoms differently. The symptoms of a megaureter may look like other conditions or medical problems. Always see your child's doctor for a diagnosis.

How is megaureter diagnosed?

Often a megaureter is diagnosed by ultrasound while a woman is still pregnant. After birth, some children may have other problems that may suggest the presence of megaureter. Children who are diagnosed later often have developed urinary tract infections that require evaluation by a doctor. This may prompt your child's doctor to do other tests, which may include:

  • Intravenous pyelogram (IVP). An imaging technique that uses an X-ray to view the structures of the urinary tract. An intravenous contrast of dye is given so that the structures can be seen on film. An IVP also reveals the rate and path of urine flow through the urinary tract.

  • Voiding cystourethrogram (VCUG). A specific X-ray that examines the urinary tract. A catheter (hollow tube) is placed in the urethra (tube that drains urine from the bladder to the outside of the body) and the bladder is filled with a liquid dye. X-ray images will be taken as the bladder fills and empties. The images will show if there is any reverse flow of urine into the ureters and kidneys.

  • Abdominal ultrasound. An imaging technique that uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function and to assess blood flow through various vessels.

  • Diuretic renal scan. A nuclear imaging technique that is done by injecting a radioactive fluid into the vein. The radioactive material is then carried to the kidneys where it gives off signals that can be picked up by cameras. Midway during the scan a diuretic medicine is given to speed up urine flow through the kidneys. This helps detect any area of blockage in the urinary tract.

  • Blood tests. Tests to check your child's electrolytes and to test kidney function.

What is the treatment for megaureter?

Your child may require antibiotics to prevent future urinary tract infections.

In some cases, the megaureter will resolve on its own over time. If there is a blockage of the urinary tract, however, surgery may be needed. The surgery  involves removing the section of the ureter that is abnormal and reconnecting the ureter.

Medical Reviewers:

  • Adler, Liora, C., MD
  • Brown, Kim, APRN