Vesicoureteral reflux

　　Under normal circumstances, the vesicoureteral junction has an anti-reflux effect similar to that of a 'valve', allowing urine to flow from the ureter to the bladder but preventing urine from refluxing into the ureter. This effect mainly depends on the length of the submucosal segment of the ureter in the bladder and the ability of the muscularis propria to maintain this length, as well as the supportive role of the detrusor muscle on the posterior wall of this segment of the ureter. When the intravesical pressure increases, the submucosal segment of the ureter is compressed and closed without causing reflux. Ureterovesical reflux (VUR) refers to the reflux of urine from the bladder back into the ureter and renal pelvis during micturition. The primary causes of this disease are mainly related to the following factors:

　　1. Ureteral Anatomical Defect

　　This leads to the outward displacement of the ureter, shortening of the submucosal segment of the ureter, thereby losing the ability to prevent reflux. The normal length-to-diameter ratio of the submucosal segment of the ureter is 5:1, while it is only 1.4:1 during reflux.

　　2. Increased Intravesical Pressure

　　When there is urinary tract obstruction (urethral stricture and advanced benign prostatic hyperplasia) or neurogenic bladder causing urinary retention in the bladder, the increased intravesical pressure destroys the anti-reflux mechanism at the vesicoureteral junction, leading to reflux.

　　3. Abnormal Ureteral Orifice

　　It is also a cause of reflux, the orifices of the ureter in the shape of a stadium, horseshoe, and golf hole are prone to reflux.

　　4. Congenital Ureteral Anomaly

　　Paraureteral diverticulum, ureteral cyst, ureteral orifice in bladder diverticulum, ectopic ureteral orifice, and other ureteral abnormalities can also cause vesicoureteral reflux.

　　Vesicoureteral reflux (VUR) refers to the reflux of urine from the bladder to the ureter and renal pelvis during urination. Reflux nephropathy (RN) is a syndrome caused by VUR and renal intrareflux (IRR) accompanied by recurrent urinary tract infections, leading to renal scarring, atrophy, and renal dysfunction. If not treated and corrected in time, it can develop into chronic renal failure. VUR not only occurs in children but also persists on the basis of recurrent UTI into adulthood, leading to renal dysfunction. Common complications include the following:

　　1, Urinary tract infection

　　Reflux allows part of the urine to reflux upwards during bladder emptying, providing a pathway for bacteria to ascend from the bladder to the renal pelvis. Therefore, reflux often occurs with urinary tract infections, and symptoms of acute pyelonephritis may appear, as well as the pathological process of asymptomatic chronic pyelonephritis. Some scholars have found that 97% of patients with renal scars have vesicoureteral reflux, and severe reflux is more likely to produce renal scars in infants.

　　2, Renal scarring

　　Among children with reflux, 30% to 60% may develop renal parenchymal scars, and the degree of renal scarring is proportional to the severity of reflux. Smellie et al. divided renal scars into 4 levels:

　　A level: Only 1 to 2 renal parenchymal scars.

　　B level: More extensive irregular scars.

　　C level: The entire renal parenchyma becomes thin, with widespread calyceal deformation.

　　D level: Renal atrophy.

　　Vesicoureteral reflux can cause upper urinary tract bacterial infection, occasionally increased renal pressure, and damage renal function. The clinical manifestations may be asymptomatic due to mild reflux, but symptoms may appear when the reflux is severe or infection occurs.

　　1, Urinary tract infection:Frequent urination, urgency, dysuria, and fever, which may present as typical acute pyelonephritis in severe cases.

　　2, Hypertension:It is a common complication in the later stage and the most common cause of malignant hypertension in children.

　　3, Proteinuria:Indicates that it has developed into renal reflux.

　　4, Developmental disorders:The disease often accompanies developmental disorders. For those with a history of chronic urinary tract infection and developmental disorders, the disease should be considered.

　　5, Renal insufficiency:Due to renal reflux, renal scarring forms, eventually leading to renal insufficiency. Among patients with chronic urinary tract infections accompanied by vesicoureteral reflux, 15% to 30% may develop renal insufficiency.

　　The disease usually occurs secondary to other congenital diseases, such as congenital ureteral malformation, paraureteral diverticulum, ureteral cyst, ureteral orifice in bladder diverticulum, and ectopic ureteral orifice, etc. These ureteral abnormalities can also cause vesicoureteral reflux. It is believed that such diseases are related to autosomal recessive inheritance and are usually associated with consanguineous marriage. There is no direct prevention for the disease.

　　Patients with a family history of suspected chromosomal abnormalities should undergo genetic screening to avoid offspring suffering from the disease due to chromosomal inheritance after marriage. At the same time, attention should be paid to strengthening prenatal nutrition, a reasonable diet, and avoiding adverse stimuli such as emotional excitement that affect embryo development.

　　The diagnosis of vesicoureteral reflux is based on clinical manifestations, imaging, and endoscopic examination, which is not difficult. At the same time, it also needs to be distinguished from other similar diseases, and the specific examination methods are as follows:

　　1, Laboratory examination

　　Urine routine examination during UTI shows purulent urine and positive urine bacterial culture. Urinalysis during RN can detect protein, red blood cells, white blood cells, and various casts. Renal function tests are normal or abnormal.

　　2, Ultrasound examination

　　By B-ultrasound, the function of the bladder ureteral junction can be estimated, the expansion of the ureter, peristalsis, and the continuity of the bladder base can be observed, and the morphology and changes of the renal pelvis and kidney can be observed. Some people insert a catheter during B-ultrasound, inject gas (such as CO2), if the gas enters the ureter, VUR can be diagnosed. Recently, color Doppler ultrasound is used to observe the function of the junction and the position of the ureteral orifice. However, B-ultrasound has limitations in detecting upper pole scars, and cannot be used for grading VUR.

　　3, X-ray examination

　　(1) Voiding cystoureterography (MCU): This is the basic method and 'gold standard' for diagnosing and grading VUR. The five-level classification method proposed by the International Reflux Committee: Grade I: urine reflux is limited to the ureter, Grade II: urine reflux to the ureter, pelvis, but without expansion, renal calyces are normal, Grade III: mild to moderate expansion and/or twisting of the ureter, moderate expansion of the pelvis, the dome is not (or) slightly blunted, Grade IV: moderate expansion and twisting of the ureter, moderate expansion of the pelvis and calyces, the dome angle is completely disappeared, most calyces maintain papillary indentation, Grade V: severe expansion and twisting of the ureter, severe expansion of the pelvis and calyces, most calyces do not show papillary indentation.

　　(2) Intravenous pyelography (IVP): Can further confirm whether there is kidney atrophy and the formation of renal scars. In recent years, it is believed that high-dose intravenous pyelography combined with X-ray section photos can better show scars.

　　4, Radionuclide examination

　　(1) Radionuclide bladder imaging: There are direct and indirect measurement methods, used to measure VUR.

　　(2) DMSA scanning technology: Used for urine sterile hotels, it is the only 'gold standard' for diagnosing children's RN, especially for children over 5 years old. Coldraich divides renal scars into four grades based on the signs of DMSA scanning photography: Grade I: one or two scars, Grade II: more than two scars, but the renal parenchyma between the scars is normal, Grade III: diffuse damage to the entire kidney, showing the symptoms of obstructive nephropathy, that is, the entire kidney atrophy, renal contour with or without scars, Grade IV: end-stage, atrophic kidney, almost no or no DMSA uptake (less than 10% of the full kidney function).

　　Patients with vesicoureteral reflux should maintain a light diet, eat more vegetables and fruits, reasonably balance their diet, and pay attention to sufficient nutrition. They should consume an adequate amount of water, at least 3000cc per day, which can be replaced by other liquids such as juice, and try to finish drinking during the day to avoid frequent urination at night. Increasing the acidity of urine, such as eating meat, eggs, cheese, plums, grains, prunes, and raisins, can also drink cranberry or小红莓汁, and can also supplement vitamin C. Avoid spicy and刺激性 food as well as cold and cool food and smoking, drinking and other habits.

　　The treatment of vesicoureteral reflux should adopt different treatment methods according to different examination results, different etiology, and different grades.

　　Firstly, Pre-treatment Precautions:

　　1. There is hope for the spontaneous resolution of reflux, which is related to the patient's age and the degree of reflux. Duckett (1983) reported that if infection can be controlled, 63% of the Ⅱ degree, 53% of the Ⅲ degree, and 33% of the Ⅳ degree reflux can resolve spontaneously. With age, many Ⅰ to Ⅲ degree refluxes can heal spontaneously, and Ⅴ degree is difficult to heal.

　　2. Long-term anti-infection treatment is safe and tolerable for children.

　　3. The presence of concurrent bladder diverticula, uninhibited bladder, etc., does not prevent the spontaneous resolution of reflux.

　　4. If the diameter of the ureter and the bladder is normal, the success rate of ureter膀胱 reimplantation surgery can reach 95% to 98%.

　　5. Reflux that persists into youth or adulthood is not easy to disappear spontaneously. Adult males with reflux may not necessarily have a pathological condition, but women, especially during pregnancy, may have problems.

　　6. Reflux without infection does not seem to cause kidney damage.

　　Secondly, Treatment Methods

　　1. Non-surgical Treatment: Mild reflux (Ⅰ degree, Ⅱ degree, Ⅲ degree) is suitable for non-surgical therapy, the purpose of which is to use medication to control urinary tract infection and prevent damage to the kidneys from pyelonephritis. Appropriate antibiotics are selected and combined with timely urination and continuous urination methods to reduce the residual urine in the bladder. Regularly review routine urine tests, urine cultures, and voiding cystourethrogram to observe the efficacy.

　　2. Surgical Treatment: Severe reflux (Ⅳ degree, Ⅴ degree), progressive aggravation of reflux that persists into adulthood, or those with recurrent exacerbation of pyelonephritis that cannot be controlled by medication all require surgical treatment. The main purpose of the surgery is to extend the length of the submucosal ureter under the bladder mucosa, and it is best to make the length of the submucosal tunnel 5 times the diameter of the ureter. For obviously dilated ureters, they need to be cut and reimplanted into the bladder after ureteronephrectomy.

　　3. Intravesical Urological Surgery: Through cystoscopy, a hardening agent is injected into the submucosa of the ureteral orifice to change the shape of the ureteral orifice and tighten it, thereby achieving the purpose of anti-reflux. Common hardening agents include: polytetrafluoroethylene (Teflon), collagen, etc.