Везикоуретеральный рефлюкс: причины, диагностика и лечение.

Vesicoureteral reflux (VUR), also known as vesicoureteric reflux, is a condition in which urine flows retrograde, or backward, from the bladder into one or both ureters and then to the renal calyx or kidneys. Urine normally travels in one direction (forward, or anterograde) from the kidneys to the bladder via the ureters, with a one way valve at the vesicoureteral (ureteral bladder) junction preventing backflow. The valve is formed by oblique tunneling of the distal ureter through the wall of the bladder, creating a short length of ureter (1–2 cm) that can be compressed as the bladder fills. Reflux occurs if the ureter enters the bladder without sufficient tunneling, i. e., too "end on".

Most children with vesicoureteral reflux are asymptomatic. Vesicoureteral reflux may be diagnosed as a result of further evaluation of dilation of the kidney or ureters draining urine from the kidney while in utero as well as when a sibling has VUR (though routine testing in either circumstance is controversial). Reflux also increases risk of acute bladder and kidney infections, so testing for reflux may be performed after a child has one or more infections. In infants, the signs and symptoms of a urinary tract infection may include only fever and lethargy, with poor appetite and sometimes foul smelling urine, while older children typically present with discomfort or pain with urination and frequent urination.

In healthy individuals the ureters enter the urinary bladder obliquely and run submucosally for some distance. This, in addition to the ureter's muscular attachments, helps secure and support them posteriorly. Together these features produce a valvelike effect that occludes the ureteric opening during storage and voiding of urine. In people with VUR, failure of this mechanism occurs, with resultant backward (retrograde) flow of urine.

Insufficient submucosal length of the ureter relative to its diameter causes inadequacy of the valvular mechanism. This is precipitated by a congenital defect or lack of longitudinal muscle of the portion of the ureter within the bladder resulting in an ureterovesicular junction (UVJ) abnormality.

In this category the ureters' valvular mechanism is initially intact and healthy but becomes overwhelmed by increased bladder pressures associated with obstruction, which distorts the ureterovesicular junction. The obstructions may be anatomical or functional. Secondary VUR can be further divided into anatomical and functional groups.

Posterior urethral valves; urethral or meatal stenosis. These causes are treated surgically when possible.

Bladder instability, neurogenic bladder and non neurogenic bladder. Bladder infections may cause reflux due to the elevated pressures associated with inflammation. Resolution of functional VUR will usually occur if the precipitating cause is treated and resolved. Medical and/or surgical treatment may be indicated.

Vesicoureteral reflux (VUR) is graded according to severity. Minimizing infections is primarily done by prophylactic antibiotics in newborns and infants who are not potty trained. However, in children who are older, physicians and parents should focus on bowel and bladder management. Children who hold their bladder or who are constipated have a greater number of infections than children who void on a regular schedule. When medical management fails to prevent recurrent urinary tract infections, or if the kidneys show progressive renal scarring then surgical interventions may be necessary. Medical management is recommended in children with Grade I III VUR as most cases will resolve spontaneously. A trial of medical treatment is indicated in patients with Grade IV VUR especially in younger patients or those with unilateral disease. Of the patients with Grade V VUR only infants are trialled on a medical approach before surgery is indicated, in older patients surgery is the only option.

Endoscopic injection involves applying a gel around the ureteral opening to create a valve function and stop urine from flowing back up the ureter. The gel consists of two types of sugar based molecules called dextranomer and hyaluronic acid. Trade names for this combination include Deflux and Zuidex. Both constituents are well known from previous uses in medicine. They are also biocompatible, which means that they do not cause significant reactions within the body. In fact, hyaluronic acid is produced and found naturally within the body.

A surgical approach is necessary in cases where a breakthrough infection results despite prophylaxis, or there is non compliance with the prophylaxis. Similarly if the VUR is severe (Grade IV & V), there are pyelonephritic changes or congenital abnormalities. Other reasons necessitating surgical intervention are failure of renal growth, formation of new scars, renal deterioration and VUR in girls approaching puberty. There are four types of surgical procedure available for the treatment of VUR: endoscopic (STING/HIT procedures); laparoscopic; robotic assisted laparoscopic; and open procedures (Cohen procedure, Leadbetter Politano procedure, Lich Gregoir technique). Laparoscopic and robotic assisted laparoscopic procedures are often imitation of classical open procedures in laparoscopic or robotic assisted laparoscopic environments.

The American Urological Association recommends ongoing monitoring of children with VUR until the abnormality resolves or is no longer clinically significant. The recommendations are for annual evaluation of blood pressure, height, weight, analysis of the urine, and kidney ultrasound. Younger children are more prone to VUR because of the relative shortness of the submucosal ureters. This susceptibility decreases with age as the length of the ureters increases as the children grow. Four times as many girls as boys are diagnosed with VUR during childhood. Boys most commonly present during their first year, and girls present more cumulatively throughout childhood.

As early as the time of Graeco Roman physician and anatomist Galen described the urinary tract and noted that there were specific mechanisms to prevent the reflux of urine.