Megaureter (dilated ureter) is an abnormality of one or both of the ureters of a child. 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 function normally. The size of a megaureter is usually greater than 10 millimeters (three-eighths of an inch) in diameter.
Complications associated with megaureter include reverse flow of urine into the kidneys and pooling of urine inside the ureter that does not drain. The pooling can cause a child to develop a urinary tract infection. In some children, complications from megaureter can cause kidney damage and failure.
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) cannot occur.
Megaureter can occur alone, but usually occurs in combination with other disorders, such as prune belly syndrome.
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 resemble other conditions or medical problems. Always consult your child's doctor for a diagnosis.
The severity of the problem often determines how a diagnosis is made. 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 perform further diagnostic tests, which may include the following:
Intravenous pyelogram (IVP). A diagnostic 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. A diagnostic 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 diagnostic nuclear imaging technique that is conducted 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 procedure a diuretic medication 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 assess your child's electrolytes and to determine kidney function.
Specific treatment for megaureter will be determined by your child's doctor based on:
Your child's age, overall health, and medical history
The extent of the disease
Your child's tolerance for specific medications, procedures, or therapies
Expectations for the course of the disease
Your opinion or preference
Your child may require antibiotic therapy as a precaution to prevent future urinary tract infections.
In some cases, medical intervention is not required because the megaureter will resolve on its own over time. If there is a blockage of the urinary tract, however, a megaureter may require surgical intervention. The surgical procedure involves removing the section of the ureter that is abnormal, reducing it, and reconnecting the ureter.