Pediatric primary vesicoureteral reflux
Introduction
Introduction to primary vesicoureteral reflux in children Vesicular ureteral reflux (VUR) refers to the influx of urine from the bladder into the ureter and renal pelvis due to abnormalities in the ureteral junction. Primary VUR is caused by an abnormality of the congenital ureteral junction without any underlying neuromuscular lesions or obstruction. Bladder ureteral reflux is divided into primary and secondary. The former is a congenital hypoplasia of the valve function, and the latter is secondary to the lower urinary tract obstruction, such as the posterior urethral valve and the neurogenic bladder. There is a close relationship between vesicoureteral reflux and urinary tract infections and renal scars, which can lead to hypertension and renal failure. In recent years, it has attracted more and more attention from domestic pediatricians. basic knowledge The proportion of illness: 0.003% Susceptible people: children Mode of infection: non-infectious Complications: urinary tract infection, hydronephrosis, hypertension
Cause
Primary vesicoureteral reflux in children
(1) Causes of the disease
1. Anatomical and physiological characteristics: The anatomical and physiological characteristics of the ureteral bladder junction are closely related to the formation of reflux. The normal ureteral muscle layer is mainly composed of loose and irregular spiral muscle fibers, which are longitudinal fibers after entering the bladder wall segment. The membrane is called Waldeyer sheath and is attached to the deep layer of the bladder triangle. The sheath acts as a valve for the ureteral bladder junction. When the bladder urinates, the sheath shrinks and the ureteral orifice closes. The urine does not turn to the ureter. flow.
2. Congenital dysplasia: The cause of reflux is the congenital anomaly of the ureteropelvic junction, mainly the longitudinal muscular dysplasia of the ureteral bladder wall, resulting in the ureteral orifice shifting, the submucosal ureter shortening, thus losing the ability to resist reflux Another reason is that the length of the submucosal ureter is not commensurate with its caliber. When there is no reflux, the ratio of the length of the submucosal ureter to its diameter is 5:1, and the reflux is only 1.4:1. In addition, next to the ureter Diverticulum, ureteral opening in the bladder fistula, ectopic ureteral orifice, bladder dysfunction, can also cause vesicoureteral reflux, the valve function of the ureteral bladder junction depends on the length of the ureter in the lower mucosa of the bladder and the muscle layer of the triangle The ability of length and the sufficient supporting effect of the bladder detrusor on the posterior wall of the ureter. In the infancy, due to abnormal development of the ureteral duct in the bladder wall, too short (less than 6mm) or horizontal position, the trigone of the bladder is immature. The valve mechanism loses its normal function; the ectopic mouth opening ectopic and abnormal morphology can affect the bladder triangle Tension, prone to reflux, detrusor instability, reflux urine from the bladder into the ureter or renal pelvis, when the bladder dilates, the urine flows back into the bladder, so that the bladder urine is incomplete, resulting in increased residual urine When the intravesical pressure rises, the submucosal ureter is compressed without regurgitation. This flap mechanism is passive, but the peristaltic capacity of the ureter and the ability to close the ureteral orifice also play a part in preventing reflux. With the increase of age, the development of the ureteral bladder junction and the bladder triangle is gradually improved, the valve function is restored, and the reflux can be gradually eliminated. The ureteral bladder connection is deformed due to the continuous increase of the intravesical pressure, which destroys the anti-reflux mechanism.
3. Urinary tract infection: Inflammatory changes of urinary tract infection often cause the valve of the ureteral bladder to lose its valve function, causing reflux. In recent years, reflux is considered to be related to genetic factors. In the family of reflux nephropathy, patients with the same reflux, Often dominant genetic or sexually linked, associated with histocompatibility antigens HLA-A3, B12, in reflux patients, familial accounted for 27% to 33%, primary is often congenital, without associated The pathogenesis of urinary neuromuscular abnormalities or obstruction is mainly caused by congenital dysplasia caused by congenital dysplasia of the ureteral bladder junction or congenital fragility of the bladder deltoid muscle. The common ureteral passage of the bladder wall is shortened, and the ureteral opening is displaced laterally or open. Golf hole sample, double renal ureter often accompanied by abnormal development of the ureteral opening, when the bladder contraction causes urine to flow back into the ureter.
(two) pathogenesis
The normal anatomy and anti-reflux mechanism of the ureteropelvic junction makes it adapt to the filling and emptiness of the bladder. When the reflux occurs for various reasons, some of the urine remains in the ureter after the bladder is empty, thus The bladder provides access to the kidneys, so reflux often complicated with urinary tract infections, which can be manifested as acute pyelonephritis or asymptomatic chronic pyelonephritis. 80% of reflux renal histological changes are consistent with pyelonephritis, Hodson, 1959 It was first discovered that renal scars were more common in children with recurrent urinary tract infections, and 97% of children with renal scars had vesicoureteral reflux. Therefore, the concept of "reflux nephropathy" was proposed. The severity of the flow is related, the more serious the reflux, the higher the chance of scar progression or new scars. The collection tubes of newborns and infants are relatively large and prone to intrarenal reflux, so small infants with severe reflux are more likely to develop kidney. The effect of scarring and reflux on renal function is the same as that of the incomplete urinary tract obstruction. When the reflux occurs, the upper urinary tract pressure increases, and the distal nephron is the first. Harm, so the tubular function is damaged earlier than the glomerulus, sterile reflux affects the ability of the renal tubules to concentrate, and lasts longer.
Glomerular function is affected by renal parenchymal damage and is proportional to the degree of renal parenchymal damage. Reversal can affect the development of the kidney, such as inhibiting its embryogenesis, leading to renal hypoplasia or abnormal renal development; and long-term reflux The diseased children have no kidney growth, and the reflux patients have a higher chance of developing hypertension. The occurrence of hypertension is related to renal scars. The more kidney scars, the higher the risk of developing hypertension, and the children with severe bilateral scars. After 20 years of follow-up, 20% had hypertension, and 8% of patients with unilateral lesions. If reflux is not effectively controlled, progressive development of renal scar can lead to renal failure. Primary vesicoureteral reflux generally increases with age. Improvement may be due to the growth and maturation of the inner segment of the bladder wall of the ureter and the muscles of the bladder triangle.
Prevention
Primary vesicoureteral reflux prevention in children
The prevention and treatment of this disease is mainly to prevent the occurrence and progress of renal damage. The most important thing is to prevent urine reflux and control infection. Anti-reflux surgery has been used in clinical practice for more than 30 years. As PVUR can gradually disappear or reduce due to aging, it is Surgical indications should be strictly limited, and Willscher et al. believe that it only applies to:
1VUR persists and is still re-infected with antibiotics.
2 severe VUR with infection, in recent years using endoscopic injection of teflon treatment, achieved good results, Normand and Smellie that ureteral implantation can not improve its prognosis, Torres et al observed the results of surgery and non-surgical patients, think There is no difference in the time from diagnosis to renal failure. In recent years, most scholars have advocated strict control of infection, waiting for VUR to disappear or reduce itself. Strictly control infection in children with VUR. After 10 years of observation, it is rare to find scar formation and progress in the kidney. Renal dysfunction.
Complication
Primary vesicoureteral reflux complications in children Complications, urinary tract infection, hydronephrosis, hypertension
Urinary tract infection, hydronephrosis, severe kidney damage can occur with hypertension and renal failure. The occurrence of hypertension is related to renal scar. The more kidney scars, the higher the risk of developing hypertension, and the children with severe bilateral scars. After 20 years of follow-up, 20% had hypertension, and 8% of patients with unilateral lesions. If the reflux is not effectively controlled, the progressive development of renal scar can lead to renal failure.
Symptom
Primary vesicoureteral reflux symptoms in children Common symptoms Abdominal pain Anorexia Children fever nausea and vomiting Urinary infections Sleepiness
The symptoms of primary vesicoureteral reflux mainly manifest from two aspects, hydronephrosis and urinary tract infection. The reflux causes the urine in the upper urinary tract to be unable to empty. To a certain extent, the renal pelvis and ureteral expansion will occur. Ultrasound reflects, therefore, all the hydronephrosis found by ultrasound should be VCUG to exclude reflux, because a considerable part of the child is asymptomatic reflux, in high-risk groups, the use of ultrasound for reflux screening has practical significance, Urinary tract infections are more non-specific in children, including fever, lethargy, weakness, anorexia, nausea, vomiting, and growth disorders.
Sterile reflux in infants and young children can be characterized as renal colic, but the performance is not typical. Large children can point out that when the bladder is filled or urinating, the ribs are painful. In elderly patients with acute pyelonephritis, there are also waist and abdominal pain. Tenderness, real-time B-ultrasound can be used as a screening test for diagnosis of reflux, urinary bladder urethrography (VCUG) is the gold standard for the diagnosis and classification of vesicoureteral reflux, the hydronephrosis and urinary system found by ultrasound examination VCUG should be performed for the onset of infection. Due to the fear and non-cooperation of the children, in order to prevent false negative results, sedatives can be given during angiography and repeated when appropriate.
Examine
Primary vesicoureteral reflux examination in children
Urinary routine light microscopy or electron microscopy scan if tube epithelial cells and abnormal red blood cells increase, should consider the presence of reflux nephropathy, proteinuria can be used as the first symptom of patients with reflux nephropathy, urine microprotein determination (including urine 2-microglobulin , 1-microglobulin, retinol-binding protein, urinary albumin) and urinary N-acetyl--glucosaminidase (NAG) increased quantitative discharge, which is helpful for the diagnosis of early reflux nephropathy and renal scar formation Severe renal damage, glomerular filtration rate decreased, urinary Tamm-Horsfall protein decreased, reflecting renal tubular dysfunction, chronic pyelonephritis, chronic renal parenchymal lesions were significantly reduced.
1. Ultrasound examination: Real-time B-ultrasound examination is suitable for diagnosing reflux sifting. If you see ureter, pyelectasis should consider the presence of reflux. Now there is color Doppler ultrasound examination, after urinary bladder filling Observe the reflux condition, and observe the position of the ureteral opening, which is conducive to early diagnosis, safe method and no pain.
2. Radionuclide cystography: can accurately determine the presence or absence of reflux, but the accuracy of the determination of reflux is not accurate, only as a follow-up study, intravenous urography can show the shape of the kidney well, through the kidney contour shown, The thickness of the renal parenchyma and the growth of the kidney can be calculated, but on the one hand, ultrasound is simpler and easier.
3. Renal nucleus (DMSA) scan: can clearly show the condition of renal scar, used to follow up the presence or absence of new scar formation, and can evaluate the function of glomeruli and renal tubules, determine the function of kidney, compare the kidney before and after surgery Features, etc.
Diagnosis
Diagnosis of primary vesicoureteral reflux in children
According to the results of urinary bladder urethrography (VCUG), the primary vesicoureteral reflux is divided into 5 grades: Grade I: reflux only reaches the ureter, grade II: reflux to the renal pelvis, but the ureter does not expand, Grade III: mild expansion or (and) curvature of the ureter, mild dilatation of the renal pelvis and mild dullness of the iliac crest, grade IV: moderate dilatation and flexion of the ureter, moderate dilatation of the renal pelvis and renal pelvis, but most renal pelvis maintain nipple morphology, Grade V: The ureter is severely dilated and distorted, the renal pelvis and renal pelvis are severely dilated, and the nipple morphology disappears in most renal pelvis.
Primary is caused by congenital vesicoureteral dysfunction, the most common, should be differentiated from secondary reflux, secondary and urinary tract infection, trauma, bladder neck and lower urinary tract obstruction, pregnancy, etc., pay attention to medical history And related clinical manifestations to help identify, the common clinical manifestations of this disease are repeated fever, abdominal pain, dysplasia and gross hematuria, etc., should be differentiated from other causes of infection, abdominal pain, dysplasia and hematuria and other diseases, there are families Sexual preference, contribute to the diagnosis of primary vesicoureteral reflux.
