Advertisement

 

Ureterocele

Most of us are born with two ureters, one from each kidney to drain the urine into the bladder. Yet what if the portion of the ureter closest to the bladder becomes enlarged because the ureter opening is very tiny and obstructs urine outflow? That is the case for people with a ureterocele. Luckily, medicine has given urologists a range of diagnostic tests and surgical techniques to deal with this abnormality. So read below to see how your urologist might correct this condition.

What happens under normal conditions?

Within the urinary tract, the kidneys filter and remove waste and water from the blood to produce urine. The urine travels from the kidneys down narrow tubes called the ureters, where it is then stored in the bladder. Normally, the attachment between the ureters and the bladder is a one-way flap valve that allows unimpeded urinary flow into the bladder but prevents urine from flowing backward (when urine flows backwards from the bladder it is called vesicoureteral reflux) into the kidneys. Approximately one out of 125 people may have two ureters draining a single kidney. One ureter drains the upper part of the kidney and the second ureter drains the lower portion. This "duplicated collecting system" is not a problem as long as each ureter enters the bladder normally. When the bladder empties, urine flows out of the body through the urethra, a tube at the bottom of the bladder. The opening of the urethra is at the end of the penis in boys and in front of the vagina in girls.

What is a ureterocele?

A ureterocele is a birth defect that affects the kidney, ureter and bladder. When a person has a ureterocele, the portion of the ureter closest to the bladder swells up like a balloon because the ureteral opening is very tiny and obstructs urine outflow. As the urine flow is obstructed, urine backs up in the ureter. Approximately 1 in 500 to 1 in 4,000 individuals are affected by this condition. In 90 percent of girls the ureterocele occurs in the upper half of a duplicated urinary tract (two ureters draining from one kidney). Approximately half of boys have a duplicated urinary tract and half have a single system. Ureterocele may be "ectopic" when a portion protrudes through the bladder outlet into the urethra, or "orthotopic" when they remain entirely within the bladder. In 5 to 10 percent of cases there is an ureterocele on both sides (bilateral). The majority of ureteroceles are diagnosed in children less than two years of age, although occasionally older children or adults are found to have an ureterocele.

What are some complications of a ureterocele?

This condition often predisposes an individual to a kidney infection. Vesicoureteral reflux is also common, particularly in individuals with a duplication of the urinary tract, because the ureterocele distorts the normal one-way valve attachment between the ureter and bladder. In addition, reflux into the opposite kidney is common for similar reasons. In rare cases, an ureterocele may prevent the passage of kidney stones. Also, the ureterocele may be so large that it completely obstructs the flow of urine from the bladder into the urethra. Occasionally, in girls, the ureterocele may sink and protrude all the way out from the opening of the urethra.

What are some symptoms of a ureterocele?

Usually a ureterocele has no symptoms. However, patients can have flank or back pain, urinary tract infection, fever, painful urination, foul-smelling urine, abdominal pain, blood in the urine (hematuria) and/or excessive urination.

How is a ureterocele diagnosed?

Usually doctors detect ureteroceles during maternal ultrasounds performed before birth, but they may not be diagnosed until a patient is being evaluated for another medical condition like a urinary tract infection.

Ultrasonography is the first imaging test used in evaluation. Additional imaging studies may also be necessary to help delineate the anatomy. One such test is a voiding cystourethrogram (VCUG), which is an X-ray examination of the bladder and lower urinary tract. A catheter is inserted through the urethra, the bladder is filled with a water-soluble contrast and then the catheter is withdrawn. Several X-ray images of the bladder and urethra are captured as the patient empties the bladder. These images allow radiologists to diagnose any abnormalities in the flow of urine through the body.

In individuals with an ureterocele, it is also important to evaluate the function of the kidneys, specifically to determine whether the affected portion of the kidney has any function. In most cases, this evaluation is performed with a renal scan.

Abdominal CT scans and MRI tests are additional studies that may also be performed in the evaluation of a patient with an ureterocele. These tests are usually performed in situations where the urinary tract anatomy is extremely ambiguous and will allow the surgeon to better identify anatomical variations.

What are some treatment options?

The timing and type of treatment are based on the age of the patient, whether the affected portion of the kidney is functioning and whether vesicoureteral reflux is present. In some cases, more than one procedure is necessary. In rare cases, observation (no treatment) may be recommended.

Because a ureterocele predisposes an individual to a kidney infection, usually an antibiotic is prescribed until the ureterocele and its complicating features have been treated. The following are available treatment options:

Transurethral puncture: A form of minimally invasive therapy is to puncture and decompress the ureterocele using a cystoscope that is inserted through the urethra. The procedure usually takes 15 to 30 minutes, and often can be done on an outpatient basis. In some cases, this treatment is unsuccessful if the ureterocele wall is thick and difficult to recognize. The advantage of this treatment is that there is no surgical incision. Risks include failure to adequately decompress the ureterocele, possibly causing urine to flow into the ureterocele, which could necessitate an open operation. In addition, there is a slight risk of causing an obstructive flap valve with the ureterocele, which can make it difficult to urinate. This treatment is best suited for ureteroceles entirely within the bladder (orthotopic) than for those that extend beyond the bladder, in which case it can be helpful, but is rarely the only treatment needed.

Upper pole nephrectomy: Often, if the upper half of the kidney does not function because of the ureterocele and there is no vesicoureteral reflux, removal of the affected portion of the kidney is recommended. In many cases, this operation is performed through a small incision under the rib cage. In more and more cases it may be performed laparoscopically.

Nephrectomy: If the entire kidney does not function because of the ureterocele, removal of the kidney is recommended. Usually this can be done laparoscopically, although at some centers it is performed through a very small incision under the rib cage.

Removal of the ureterocele and ureteral reimplantation: If it is deemed necessary to remove the ureterocele, then an operation is performed in which the bladder is opened, the ureterocele is removed, the floor of the bladder and bladder neck are reconstructed and the ureters are reimplanted in such a way to create a non-refluxing connection between the ureters and the bladder. The operation is performed through a small lower abdominal incision. The success rate with this procedure is 90 to 95 percent. Complications include vesicoureteral reflux or obstruction.

Ureteropyelostomy or upper-to-lower ureteroureterostomy: If the upper portion of the ureter shows significant function, one option is to connect the obstructed upper portion to the non-obstructed lower portion of the ureter or pelvis of the kidney. The operation is done through a small lower abdominal incision. The success rate with this procedure is 95 percent.

Frequently asked questions:

Is there any way to prevent this condition?

There is no known prevention for this condition; it is present at birth but may not be discovered until later in life.

My baby was diagnosed with an ureterocele on a prenatal ultrasound. She seems very healthy. Is it absolutely necessary for her to undergo treatment?

In the past, most children with an ureterocele had their condition detected following a serious kidney infection, which often required hospitalization for intravenous antibiotics. Consequently, it would be unusual for her not to develop a urinary tract infection unless her ureterocele was treated.

My doctor has recommended that my daughter take antibiotic prophylaxis because she has an ureterocele and urinary reflux. Is it safe to take antibiotics every day?

Many children and adults take a low dose of an antibiotic every day to prevent urinary tract infections. This form of therapy has been used for over 35 years and has proven to be relatively safe, as long as the dose is maintained at one-fourth to one-half the full dose. Although we recognize that using antibiotics has some downsides, one needs to weigh the risk of taking the antibiotic against the risk of a serious kidney infection if the antibiotic were not taken.

My child was diagnosed with an ureterocele and it was punctured through a small scope. Now there is reflux into the ureterocele and the lower part of the kidney also. Will more surgery be necessary?

In most cases, if there is reflux up the ureter into the lower part of the kidney and/or the ureterocele, the reflux is unlikely to disappear with time and removal of the ureterocele and ureteral reimplantation is often necessary.