Posterior urethral valve

Introduction to posterior urethral valve Posterior urethral valve, the most common urinary tract obstruction in infants and neonates, occurs only in male patients. The valve is usually located at the distal end of the prostatic urethra. The valve is formed by mucosal folds and looks like a thin film. . When urinating, the valve can cause different degrees of obstruction, and the posterior urethral valve is an important cause of renal failure. basic knowledge The proportion of illness: 0.005% Susceptible people: good for male babies and newborns Mode of infection: non-infectious Complications: urinary retention, chronic renal failure, cryptorchidism, renal hypoplasia

Posterior urethral valve disease

Bladder dysfunction (20%):

About 25% of children with posterior urethral valvular disease have varying degrees of bladder dysfunction, mostly manifested as urinary incontinence, which was thought to be related to sphincter disorders in the past (because the valve is at the level of the sphincter, the urethra and bladder neck are abnormally developed), urine The appearance of flow dynamics examination has made people realize that posterior urethral valve disease combined with primary bladder dysfunction, and will not be relieved after the removal of posterior urethral obstruction, and will affect the prognosis of children, from different related posterior urethral valve Reports of children with symptoms found that children with this disease often have several abnormalities of bladder detrusor function, including primary myogenic disorders, non-inhibitory bladder, low compliance bladder, and bladder dysfunction. Urinary incontinence, and manifested as increased bladder and ureteral pressure, leading to renal dysfunction, while bladder dysfunction in children with urinary incontinence is more serious than normal urinary control, treatment should be from bladder dysfunction and emptying ability For entry point, cholinergic drugs to reduce uninhibited detrusor contraction, intermittent catheterization to provide satisfactory bladder emptying Bladder surgery necessary to increase bladder capacity and improve their compliance, timed voiding the bladder to maintain the low pressure chamber to reduce the pressure and urinary advantageously improve renal function.

Bladder ureteral reflux (20%):

Is one of the common complications of posterior urethral valve disease, in the first diagnosis of the disease, 1/3 to 1/2 of the children with vesicoureteral reflux, most of which are secondary to increased intravesical pressure, ureteral diverticulum There is a loss of function in the ureteral junction of the bladder. In some cases, vesicoureteral reflux is primary, due to dysplasia of the ureter, and the mortality of the posterior urethral valve combined with bilateral ureteral reflux is greater than 57%. The rate was 17%, and the no-flow was 9%.

In treated children with posterior urethral valvular disease, approximately one-third of cases have spontaneous remission of ureteral reflux after the removal of posterior urethral obstruction; another 1/3 of cases may continue to exist, but reflux under drug treatment Does not cause problems; the rest of the children during the follow-up process, if the ureteral reflux is aggravated, ureteral bladder replantation should be performed as soon as possible.

Hydronephrosis (10%):

In cases of obvious obstruction of the urethra and obvious expansion of the ureter in different degrees, after endoscopic resection of the urethral valve or cystostomy, once the obstruction is relieved, the hydronephrosis will gradually reduce. If the hydronephrosis is not relieved, it is necessary to think whether there is a ureter. Obstruction of the bladder junction, ureteral dynamic obstruction can not produce effective peristalsis, whether hydronephrosis is secondary to increased intravesical pressure or increased urine flow, these factors will have different effects in different cases, some scholars pointed out After urethral valve resection, the diameter of the ureter is reduced, and the remission of hydronephrosis will take several years. It is recommended that further surgical treatment of the ureter can be considered when renal function is stable and urinary tract infection can be controlled.

Bladder urodynamic examination suggests that children with low compliance bladder and increased intravesical pressure must be corrected before ureteroplasty. Urodynamic examination of the upper urinary tract is beneficial for ureteral non-obstructive dilatation and ureteropelvic connection. Identification of obstruction, diuretic nephrogram for renal dysfunction, dilute, high-flow urine, ureteral dilatation, etc., at this time percutaneous puncture, upper urinary tract pressure and urine flow measurement (Whitaker test) is usually very Necessary, the measurement of urine flow is also very important, many children with posterior urethral valve disease have obvious hypotonic urine, like children with primary diabetes insipidus have high urine flow will also cause continuous ureter expansion.

Effect on kidney function

Due to the influence of ureteral hypertension, almost half of the children have obvious urinary concentrating dysfunction. The purpose of treatment for posterior urethral valve disease is to maximize the preservation of renal function. In the early stage of understanding post-urethral valve disease (30 years ago), there are about 25 % of children die within 1 year of age, 25% die during childhood, and about 50% survive to adolescence with varying degrees of renal dysfunction. Now, neonatal deaths due to renal dysfunction and sepsis are rare. See, the cause of death in neonatal period is mostly combined with lung dysplasia and respiratory failure, however, children with posterior urethral valve disease may have severe renal dysfunction at birth, even after lifting the obstruction, due to urine Infection or retention may lead to infection due to impaired renal function and hypertension. Renal function disorders may be renal parenchymal dysplasia, hydronephrosis, infectious renal atrophy or may be progressive due to renal ultrafiltration. The result of glomerular sclerosis.

Posterior urethral valve disease is associated with renal parenchymal dysplasia, which is characterized by microencapsulated renal parenchyma, especially in the peripheral zone of the renal cortex. This may be due to the development of the posterior renal embryo base with increased intraluminal pressure. As a result, some scholars have pointed out that the cause of posterior urethral valve disease complicated with renal dysplasia is caused by abnormal development of primary embryo, which is characterized by abnormal position of ureteral germ development, so common VURD syndrome (valve, one side vesicoureteral reflux, Kidney dysplasia is also one of the abnormalities of ureteral germ development. Some complications also play a buffering role on kidney damage, such as massive unilateral vesicoureteral reflux, larger bladder diverticulum and urinary ascites. Reducing the pressure in the cavity plays a positive role.

Due to urinary tract obstruction caused by posterior urethral valve disease, the increase of ureteral pressure first affects the most distal nephrons. Some children with impaired urinary concentrating function are more severely damaged than glomerular filtration rate, resulting in increased urine flow and serious Dehydration and electrolyte imbalance are at the same time, and increased urinary flow causes ureter and bladder dysfunction as described above.

Posterior urethral valve prevention

The best way to protect the kidneys and bladder function is early detection. The prenatal fetus should be examined by ultrasound. The newborn is carefully examined for physical examination, urine is observed and urine is tested. Nitrogenemia and prolonged urinary tract infection occur. Even if the obstruction has been lifted, the prognosis is very poor.

Posterior urethral valve complications Complications, urinary retention, chronic renal failure, cryptorchidism, renal hypoplasia

Can cause urinary retention, even vesicoureteral reflux, kidney, ureteral water, leading to renal atrophy or cystic changes, chronic renal failure, so the urethral valve damage to the urinary system, the consequences are serious, the urethral valve can be combined Cryptorchidism, fine hypertrophy or renal hypoplasia.

Posterior urethral valve symptoms Common symptoms Urinary frequency dysuria High fever Ascites fecal incontinence Painful enuresis Inability to dehydrate hematuria

First, the symptoms

Urinary dysfunction

Older children can be found by their loved ones with symptoms of dysuria, need to add abdominal pressure when urinating, frequent urination and urinary flow, even overflowing urinary incontinence, enuresis is more serious and stubborn, but young people can not be stated and easy to be Relatives ignored.

2. A suprapubic or lumbar mass

This is a common sign, due to urinary dysfunction caused by bladder urinary retention and secondary hydronephrosis, and because the child's abdominal wall and waist muscles are weak, the bladder filled with bladder and water is easy to reach, and the waist pain during urination suggests vesicoureteral reflux .

3. Developmental and malnutrition

Due to renal dysfunction leading to development and malnutrition, the height, weight and mental development of the child are later than the actual age, often with anemia and hypoproteinemia.

4. Renal dysfunction

Renal function test showed a decrease in concentrating function. In severe cases, blood BUN and Cr increased, and there were metabolic acidosis and electrolyte imbalance.

5. symptoms of urinary tract infection

Often due to secondary pyelonephritis, high fever, chills, pyuria and hematuria.

6. Other

Some neonates exhibit respiratory distress syndrome or unexplained pneumothorax or mediastinal emphysema, often due to posterior urethral valve with pulmonary dysplasia.

Second, the urethral obstruction caused by this disease is extremely damaging to the urinary system. It should be diagnosed early and treated promptly. Anyone with the following clinical symptoms should consider the possibility of having a urethral valve and should be further examined.

Newborn

(1) There are unexplained mediastinal emphysema or pneumothorax complicated by respiratory disorders.

(2) There are cystic masses in the bilateral lumbar and/or suprapubic areas.

(3) fetal urine ascites.

(4) too little amniotic fluid (due to urethral obstruction, less fetal urine discharge).

(5) There is significant dehydration at birth.

Early childhood

(1) Frequent urination, urinary tract weakness, difficulty urinating, urinary incontinence, enuresis.

(2) Repeated urinary tract infections, pyuria, hematuria.

(3) The waist can touch the mass, especially the double waist mass.

(4) bladder urinary retention.

(5) Developmental disorders.

(6) Chronic renal insufficiency.

Posterior urethral valve examination

Laboratory examination

Generally, there are azotemia and renal concentrating function. Patients with chronic infection may have anemia and infectious urine. Serum creatinine, urinary nitrogen and creatinine clearance rate are the best indicators to reflect the degree of renal dysfunction.

2. Prenatal ultrasound examination

Posterior urethral valve disease accounts for 10% of urinary tract malformations detected before delivery. The detection rate is located in the ureteropelvic junction obstruction, congenital giant ureteral disease, ranking third, the characteristics of ultrasound are:

1 more visible kidney, ureteral water;

2 the bladder wall is thickened, and the bladder has urinary sputum;

3 prostatic urethra dilatation, prolonged;

4 maternal amniotic fluid is small, because it is often atypical, easy to be confused with plum dry abdominal syndrome and bilateral moderate vesicoureteral reflux, these changes must be reviewed after the birth of the child.

3. Urine flow rate measurement

It has a screening significance for children's dysuria.

4. Urethral angiography

Urethral angiography is of great value in diagnosis. Urinary bladder urethrography is more valuable. The most common type I can be seen in the valve with a thin layer of filling defect, the defect of the proximal posterior urethra, and the bladder neck muscles. It seems to have a narrow stenosis. When the posterior urethra is extremely dilated, it is connected with the bladder neck. It looks like a gourd. The distal urinary flow is extremely thin, and it can be seen to flow back into the reproductive tract. Half of them have vesicoureteral reflux (unilateral or bilateral). Type II and type III (except for the proximal end of the sputum), the posterior urethra does not dilate, and the type III of the diaphragm has a diaphragm at the proximal end. When retrograde urography is performed, the contrast agent is blocked at the diaphragm, and the contrast agent stays at In the posterior urethra, the diaphragm is spheroidally bulged toward the bladder. Retrograde urography and urinary bladder urethrography contrast examination have a greater diagnostic value.

5. Urethoscopy

The valve can be seen directly, which is also valuable for diagnosis, but the detection rate is not higher than that of bladder urethrography.

6. Venous urography

Except for bilateral kidney and ureteral hydrops, the renal concentrating function is poor. The degree of water accumulation on both sides may be inconsistent. It may also be unilateral. When renal function is lost, intravenous pyelography may not be developed. The renal pelvis and ureter are normal. Completely exclude the urethral valve.

7. Nuclide kidney map

Bilateral or unilateral obstructive manifestations can be found to be valuable for understanding renal function.

8. Renal radionuclide scanning

Can understand the function of both kidneys.

Diagnosis of posterior urethral valve

diagnosis

Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.

Differential diagnosis

Congenital bladder neck contracture

More common in children, due to bladder neck muscle, fibrous tissue hyperplasia and chronic inflammation, leading to bladder neck stenosis and urinary tract obstruction, dysuria, urinary retention, vesicoureteral reflux, renal ureteral hydrops, renal dysfunction and repeated Attack of urinary tract infection, rectal examination, can touch the bladder neck lumps, urinary bladder urethra angiography, showing bladder outlet elevation. The bottom of the bladder is round, bladder urethroscopic examination, when the examination mirror passes through the bladder neck Tightness, the neck is narrow and narrow, the posterior lip is ridge-like, the triangle is hypertrophy, and the bottom of the bladder is concave.

2. Congenital fine hyperplasia

Congenital enlargement, intrusion into the urethra, formation of obstruction caused by urinary dysfunction, may have dysuria, urinary weakness, frequent urination, urinary incontinence, enuresis, renal insufficiency, water and electrolyte disorders, urethroscopic examination Visible bulge, hypertrophy, urinary bladder urethra angiography, visible urethral filling defect, urethral dilatation, vesicoureter regurgitation.

3. Prostatic hyperplasia

Is a common disease associated with endocrine disorders in elderly men, manifested as lower urinary tract obstruction, dysuria, weak urine flow, fine urinary tract, pubic sputum and filling bladder, can touch the enlarged kidney, severely affect renal function When the urethral valve occurs in the elderly, it can be confused with it. The rectal examination can touch the smooth surface, the enlarged prostate with elasticity, protruding into the rectum, the middle groove becomes shallow or disappears, and the prostate can be seen by ultrasonic examination. The line is enlarged, there is more residual urine, the bladder angiography shows the bottom of the bladder is raised, the distance between the lower edge and the pubic bone is widened, the bladder wall has trabeculae, diverticulum, urethra angiography shows that the urethra is prolonged and enlarged, but the edge is smooth, cystoscopy The middle lobe of the prostate can be seen, and the leaves on both sides protrude into the cavity, and the bladder wall has trabeculae and a small chamber shape.

4. Urethral stricture

For the congenital, inflammatory, injurious, iatrogenic and other causes of urethral fibrous tissue hyperplasia, leading to urethral lumen stenosis, dysuria, urinary retention, and even secondary infection, for urethral probe examination, in the stenosis The segment was significantly blocked and urethrography showed a narrow segment.

5. Neurogenic bladder

The system controls the urinary dysfunction caused by damage to the central or peripheral nerves of urination, which may cause urinary retention, hydronephrosis, renal dysfunction and secondary urinary tract infections, and generally has a history of nerve injury caused by trauma or surgery, or Diabetes, poliomyelitis and other systemic disease history, or history of drug application, in addition to dysuria and other symptoms, there are constipation, fecal incontinence, decreased or disappeared bladder swelling, perineal sensation diminished or lost, anal sphincter hypotension Or enhanced, limb paralysis and other manifestations, may have spina bifida, meningocele, tibia dysplasia and other malformations, bladder angiography showed that the bladder is pine-shaped, bladder denervation hypersensitivity test positive.

6. Polycystic kidney

It is a congenital renal polycystic lesion, mostly bilateral, and 1/3 of the cases are found in children. The kidneys are nodular, and can be found in the upper abdomen, lumbar lumps, and kidney masses. Hypertension and chronic renal function can occur. Depletion, but often intermittent painless macroscopic hematuria, the renal shape increased in the excretory urography, the renal pelvis and renal pelvis compression deformation, stenosis, prolongation, enlargement, defect or displacement, ultrasound examination The multiple liquid dark areas are shown, and the radionuclide renal kidney scan shows multiple defect areas, and the kidney shows impaired renal function.

7. Chronic nephritis

It is a chronic diffuse glomerular damaging disease of bilateral kidneys mainly composed of proteinuria, tubular urine, hematuria and edema, hypertension, and renal dysfunction. It is more common in children and adolescents, and its renal dysfunction can be compared with the urethra. The valve is confused, but there is no sign of dysuria, urine protein and cast is unique, urethrography, cystoscopy and urine flow rate are normal.

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