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Vesicoureteral reflux in children
Last reviewed: 12.07.2025
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Vesicoureteral reflux in children is a pathological condition characterized by the reverse flow of urine from the bladder into the upper urinary tract due to a disorder of the valve mechanism of the ureterovesical segment.
Anatomy of the vesicoureteral segment: the ureterovesical junction (UVJ) consists of a juxtavesical part, an intramural section and a submucosal part ending with the ureteral orifice. The length of the intramural section increases from 0.5 to 1.5 cm depending on age.
The anatomical characteristics of the normal mechanism of the ureterovesical junction include an oblique entry of the ureter into the Lieto triangle and a sufficient length of its intravesical portion. The ratio of the length of the submucous tunnel to the diameter of the ureter (5:1) is the most important factor determining the efficiency of the valve mechanism. The valve is mainly passive, although there is also an active component provided by the ureterotrigonal muscles and urethral membranes, which close the mouth and submucous tunnel of the ureter at the moment of contraction of the detrusor. Active peristalsis of the latter also prevents reflux.
The peculiarity of the vesicoureteral segment in young children is the short internal section of the ureter, the absence of Waldeyer's fascia and the third layer of muscles of the lower third of the ureter, different angles of inclination of the intravesical part of the ureter to its intramural section (a right angle in newborns and an oblique angle in older children), weakness of the muscular elements of the pelvic floor, the intramural section of the ureter, the fibromuscular sheath, and Lieto's vesical triangle.
In newborns, the Lieto triangle is located vertically, as if it were a continuation of the posterior ureteral wall. In the first year, it is small, poorly expressed and consists of very thin, tightly adjacent smooth muscle bundles separated by fibrous tissue.
The occurrence and progression of vesicoureteral reflux at an early age is facilitated by underdevelopment of the neuromuscular apparatus and the elastic framework of the ureter wall, low contractility, and disruption of the interaction between ureteral peristalsis and bladder contractions.
[ Causes of Vesicoureteral Reflux in Children
The etiology and pathogenesis of vesicoureteral reflux have been studied for over 100 years, but to this day they have not become clearer to a significant number of clinicians and morphologists. Existing points of view on the causes and mechanism of development of vesicoureteral reflux are sometimes so contradictory that even now this issue cannot be considered fully resolved.
Vesicoureteral reflux occurs equally in boys and girls. However, before the age of one year, the disease is diagnosed predominantly in boys in a ratio of 6:1, while after 3 years, it is diagnosed most frequently in girls.
Symptoms of Vesicoureteral Reflux in Children
The clinical picture of vesicoureteral reflux may be vague, and this condition is detected during examination of children with complications of vesicoureteral reflux (for example, pyelonephritis).
However, there are general symptoms characteristic of children with vesicoureteral reflux: delayed physical development, low birth weight, a large number of stigmas of dysembryogenesis, neurogenic dysfunction of the bladder, repeated "causeless" increases in temperature, abdominal pain, especially associated with urination. However, these symptoms are characteristic of many diseases.
Diagnosis of vesicoureteral reflux in children
Inflammatory changes in the kidneys and urinary tract may be accompanied by isolated urinary syndrome, mainly leukocyturia. Proteinuria is more common in older children, and its occurrence in young children indicates gross renal changes against the background of vesicoureteral reflux.
The main method for diagnosing vesicoureteral reflux is micturition cystography, during which, depending on the degree of reflux of the radiocontrast agent, five degrees of vesicoureteral reflux are distinguished.
How to examine?
What tests are needed?
Treatment of vesicoureteral reflux and reflux nephropathy in children
When choosing a treatment plan for vesicoureteral reflux and its complications, a finely differentiated approach is necessary, because surgical intervention on a relatively immature vesicoureteral segment can interrupt the natural maturation process and affect the function of the urinary system organs in the future. In addition, differential diagnostics of the causes of reflux (developmental defect, morphofunctional immaturity or inflammation) is difficult, which is especially typical for children under three years of age.
But it is necessary to remember that vesicoureteral reflux should be treated from the moment the pathology is detected. Indications for surgical treatment of vesicoureteral reflux are considered to be vesicoureteral reflux of the 3rd degree with the ineffectiveness of conservative therapy for 6-12 months; vesicoureteral reflux of the 4-5th degree.
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