Megaureter (MO) is usually found during prenatal testing and is the most common cause of fetal hydronephrosis. Giant ureters are divided into primary and secondary.
Giant ureters , according to medical statistics, are the second most common cause of hydronephrosis found in the fetus during prenatal ultrasound. This defect affects 1 in 10,000 births. The disease is four times more common in male newborns. Bilateral giant ureters are diagnosed in approximately 20% of children with this defect. Almost 85% of giant ureters do not require surgical treatment as they resolve on their own.
The ureter, or actually the ureters, are the paired organs (tubes) that connect the renal pelvis to the bladder. Their main task is to drain urine from the cup-pelvic system of the kidney into the bladder.
In a properly developed organism, the ureters have a diameter (lumen) of 3-5 millimeters. We talk about giant ureters (ureter) when its light differs from the values given above, i.e. from the accepted norm. It even happens that the diameter of the ureter may exceed 7 millimeters. The ureter may be dilated on one or both sides of the body.
Giant ureter - division
Giant ureters are divided into primary and secondary depending on the cause of their formation.
- Primary giant ureteris characterized by significant dilation of the ureter, but also no organic cause for dilation. There is no bladder obstruction, and the vesicoureteral junctions and the patency of the intramural ureter are normal. Another division may be the division into giant obstruction, outflow, obstruction-outflow, non-obstructive and non-outflow ureters.
- Secondary giant ureteroccurs in neurogenic bladder and posterior urethral valve defects. In both cases, there is an increase in intravesical pressure, which leads to a secondary dilation of the upper urinary tract.
Giant ureter - causes
The causes of primary giant ureters are not fully understood.
In the case of secondary giant ureters, it is referred to as vesicoureteral reflux, neurogenic bladder andposterior coil valve.
One of the most frequently cited theories explaining the formation of giant ureters is the abnormal function of the intramural segment of the ureter combined with impaired peristalsis of the ureter.
It is assumed that disturbances in the peristalsis of the intramural segment are caused by its neuromuscular immaturity or an abnormal structure of the ureteral wall.
There is also an abnormal arrangement of muscle fibers or an excess of collagen.
Another cause of the formation of a giant ureter is the aperist altic intramural segment of the ureter, which hinders the flow of urine with the progressive widening of the ureter above the aperist altic segment.
Secondary giant ureters are associated with the neurogenic bladder.
Giant ureters are often accompanied by their ectopic (displaced) location. The most common location for the opening of the ureter is then the bladder neck, urethra, vagina or epididymis.
Ureteral ectopy is more common in girls.
Giant ureter - symptoms
In nearly 50% of newborns, the giant ureter does not cause any symptoms.
The remaining patients have recurrent urinary tract infections. It is often pyelonephritis.
Some patients experience damage to the parenchyma of the kidneys over time, which can lead to organ failure.
Children with symptomatic giant ureters may have weight deficiency and eating disorders.
Giant ureter - diagnosis
The basic examination that allows to recognize the giant ureter is ultrasound. Ultrasound allows for the differentiation of the narrowing of the pyeloureteral junction and the giant ureter. The test also allows for the assessment of the thickness of the renal parenchyma, wall thickness and residual urine after voiding.
Another test is voiding cystourethrography, which is performed when giant ureters are suspected. The test excludes vesicoureteral reflux.
Voiding cystography is the injection of a contrast agent into the bladder through a thin catheter. The examination is performed in an X-ray laboratory. After administering a contrast agent, an X-ray is made during voiding. With reflux, a regression of contrast from the bladder to the ureters or to the kidney is observed.
Scintigraphy is a less burdensome test than urography. It consists in administering a special radiotracer intravenously and observing its excretion by the kidneys with a special gamma camera. Scintigraphy allows the assessment of kidney function and the degree of outflow disordersurine. A typical image in scintigraphy is obstructed passage of the radiotracer or complete stagnation in the uretero-bladder junction.
Giant ureter - treatment
In 80% of giant ureters no treatment is given as this defect resolves spontaneously.
Children who have recurrent urinary tract infections must take antibiotics prophylactically and undergo ultrasound examinations from time to time.
In cases where the ureters widen systematically and the functioning of the kidneys is impaired, surgical treatment is used.
It is worth adding, however, that the degree of deformation and the degree of dilation of the ureters do not affect the severity of the disease.
Surgical treatment is required by 15 - 20% of children with ureter or giant ureters. Qualification for surgical treatment is made on the basis of the clinical picture and the results of imaging tests.
Recurrent pyelonephritis, progressive renal failure confirmed by scintigraphy are the most important indications for surgery.
Giant ureter - types of treatments
The aim of the treatment of a giant ureter is to transplant it and possibly narrow its lumen.
The operation is not performed in children under the age of one due to unfavorable anatomical and functional conditions. The reason is the detrusor muscle, which is overactive in infants and generates much more intravesical pressure than in older children.
The operation can be performed when the child reaches the age of one and weighs more than 10 kilograms.
If it is necessary to perform the procedure on a younger child, the first stage of treatment is the creation of a ureterocutaneous fistula. The surgeon may use one of five techniques to create a fistula. The decision is made after analyzing the child's build. A lot also depends on the experience and preferences of the surgeon.
Before the operation, it is necessary to perform urethrocystoscopy in each patient, i.e. endoscopy of the urethra and bladder. The examination is performed in an operating room and under general anesthesia. The aim of this examination is to exclude defects within the urethra (posterior urethral valve) and to assess the location of the ureteral orifices and the anatomy of the urinary bladder.
Surgical treatment consists of excision of the distal, narrowed section and transplantation of the giant ureter to a new place, within the urinary triangle. In some patients, the lumen of the ureter becomes narrower.
The operation of a giant ureter is in progressapprox. 60-90 minutes. Due to the risk of complications, the procedure is only performed on one side of the body.
The choice of the surgical technique depends on the anatomical conditions. The operator takes into account the bladder capacity and the degree of ureteral dilation. The most common types of surgery are Politano-Leadbetter, Paquin or Cohen.
Regardless of the surgical technique, the idea is to obtain a long submucosal segment of the ureter that will prevent ureteral outflow.
After the ureter is transplanted, a ureteral catheter is inserted into its lumen, which is led out through the abdominal wall. In addition to the ureteral catheter, a Foley catheter and drains are left in the bladder.
Giant ureter - after surgery
After the procedure, the child goes to the recovery room and then to the urology ward.
Drains from the peri-bladder area are removed as soon as the leakage ceases.
The catheter from the ureter is removed after 5-14 days, which depends on the healing process and the rules of a given center.
The Foley catheter is removed after 10-4 days. Only after that can the child go home. Regular he alth checks are also necessary.
About the author
Anna Jarosz A journalist who has been involved in popularizing he alth education for over 40 years. Winner of many competitions for journalists dealing with medicine and he alth. She received, among others The "Golden OTIS" Trust Award in the "Media and He alth" category, St. Kamil awarded on the occasion of the World Day of the Sick, twice the "Crystal Pen" in the national competition for journalists promoting he alth, and many awards and distinctions in competitions for the "Medical Journalist of the Year" organized by the Polish Association of Journalists for He alth.
Read more articles by this author