A ureterocele is a congenital abnormality of the urinary tract that primarily affects the tubes connecting the kidneys to the bladder. The condition involves a ballooning of the lower end of the ureter. This structural issue, present at birth, can impede the normal flow of urine from the kidney into the bladder. Although serious, a ureterocele is generally manageable with appropriate medical intervention, often leading to a good long-term outcome.
Anatomy and Definition
The urinary system relies on the ureters, which are muscular tubes that transport urine from the kidneys to the bladder. A ureterocele occurs when the segment of the ureter that passes through the bladder wall balloons out, creating a sac-like pouch inside the bladder. This cystic outpouching forms at the distal part of the ureter.
The swelling can vary significantly in size. The resulting pouch can partially or completely obstruct the ureter’s opening, preventing urine from draining efficiently. The blockage causes urine to back up into the ureter and the kidney, a condition known as hydronephrosis. This backup can lead to dilation of the ureter (hydroureter) and the kidney’s collecting system, potentially causing damage to the kidney over time.
Causes and Categorization
A ureterocele is classified as a congenital defect, developing during fetal growth due to the abnormal formation of the ureteral end where it connects with the bladder. One theory suggests the cause involves the failure of the temporary Chwalla membrane to regress completely.
The condition is categorized based on its location relative to the bladder:
Orthotopic (Intravesical) Ureterocele
This type is entirely contained within the bladder. It often affects a single collecting system (one ureter per kidney) and is more frequently diagnosed in adults.
Ectopic (Extravesical) Ureterocele
This type extends beyond the bladder into the bladder neck or the urethra. Ectopic ureteroceles are more common in children and are often associated with a duplicated collecting system. The ureterocele typically forms on the ureter draining the upper portion of the kidney.
Detection and Clinical Presentation
Many ureteroceles are discovered before birth during routine prenatal screening. A fetal ultrasound, typically performed around 20 weeks of pregnancy, may reveal swelling or dilation of the kidney or ureter, alerting healthcare providers to the possibility. Diagnosis is then confirmed after birth using further imaging tests.
When not found prenatally, the condition usually presents with symptoms leading to a postnatal diagnosis. The most frequent clinical presentation is a urinary tract infection (UTI), which occurs because the obstruction causes urine to stagnate, creating a favorable environment for bacteria. Symptoms of a UTI can include painful urination, fever, foul-smelling urine, or blood in the urine.
In infants, fever or failure to thrive may raise suspicion. Older children and adults may experience flank or abdominal pain caused by kidney swelling, or they may develop kidney stones.
For diagnosis, an ultrasound of the kidneys and bladder is the initial imaging test. A voiding cystourethrogram (VCUG) is often used to assess the bladder and lower urinary tract, checking for the backward flow of urine (vesicoureteral reflux) and helping to fully visualize the ureterocele. A nuclear renal scan is also performed to measure the function of each kidney and determine the extent of any damage caused by the obstruction.
Treatment Approaches
Treatment for a ureterocele is highly individualized, depending on the size, the patient’s age, and the degree of obstruction and kidney function. The main goals are to relieve obstruction, prevent recurrent infections, and preserve kidney function.
For small, asymptomatic ureteroceles that do not cause significant obstruction, watchful waiting and monitoring may be adopted. However, surgical intervention is necessary for most symptomatic or obstructive cases.
The least invasive option is an endoscopic incision or puncture, often the first-line treatment for intravesical ureteroceles. This procedure involves passing a cystoscope through the urethra to the bladder and making a small incision into the ureterocele to decompress the sac and restore urine flow. This minimally invasive technique is highly effective at immediately relieving the obstruction.
For larger, ectopic, or more complicated cases, a more extensive reconstructive surgery may be required. This could involve ureteral reimplantation, where the ureterocele is removed, and the ureter is surgically repositioned and reattached to the bladder wall to prevent reflux. Another element is heminephrectomy—surgical removal of the non-functioning upper pole of the kidney—which may be performed when the obstructed part of the kidney is severely damaged.