What Are Posterior Urethral Valves?

Urinary tract mucosal folds are hypertrophy, adhesion, or abnormal development, which protrude into the urethral cavity, resulting in obstruction of urinary flow. Occurred in the near and far ends of Jingfu.

Posterior urethral valve

The posterior urethral valve is usually located at the distal end of the prostate urethra. The valve is formed by mucosal folds and looks like a thin film. Urinary tract mucosal folds are hypertrophy, adhesion, or abnormal development, which protrude into the urethral cavity, resulting in obstruction of urinary flow.

Causes of posterior urethral valve

It starts at the far end of Jingfu, one for the first, and then divided into two, which travel outwards, ending in the posterior wall and the side wall of the urethra. A gap is formed in the middle. Its concave surface is upward, like a one-way open valve from bottom to top. As a result, urinary flow is blocked, the urethra above the valve is dilated and stretched, the bladder neck is hypertrophic, and it protrudes into the urethra.

Posterior urethral valve is the most common urethral obstruction disease in infants and newborns.

This disease only occurs in male children. The valve is usually located at the distal end of the prostate urethra. The valve is formed by mucosal folds and looks like a thin film. During urination, the valve can cause varying degrees of obstruction.

Clinical manifestations of posterior urethral valve

Symptoms and Signs: Children with posterior urethral valves may experience symptoms of micturition obstruction to an insignificant degree. Frequent urethral weakness, interrupted urination, endless dripping, urinary tract infections, and sepsis. Severe obstruction can cause hydronephrosis, which can touch the mass in the abdomen, and the swollen bladder in the lower abdomen. A few patients can reach the hydronephrotic kidney on both sides of the costal belly. Most children have stunted growth after birth, but no other findings can be found in vitro except for signs of chronic diseases.

Posterior urethral valve examination

Laboratory tests: Nitrosemia and impaired renal concentration are common. Patients with chronic infection may develop anemia and infectious urine. Serum creatinine, urinary nitrogen and creatinine clearance are the best indicators of the degree of renal impairment.

X-ray examination: Excretory cystourethrography is the best way to diagnose post-urethral valve. Patients with a large amount of residual urine should undergo urinary catheterization before taking the film, and the urine extracted from the catheter is routinely sent to culture. Long-term severe obstruction, cystography can find bladder ureteral reflux and bladder trabecula formation. On excretory urethral osteotomy films, it can often show posterior urethral elongation and expansion, and bladder neck elevation; excretory urography can show Hydronephrosis.

Ultrasound examination: In children with severe azotemia, ultrasound examination can detect hydronephrosis and enlarged bladder. If the fetus at 28 weeks of pregnancy has hydronephrosis and bladder enlargement, it is a typical posterior urethral valve sign.

Device examination: under general anesthesia, urethral microscopy and cystoscopy, the formation of trabecular trabeculae, a few can also be seen in the diverticulum, and bladder neck, triangular area hypertrophy, and the valve can be seen directly in the distal urethra and clear diagnosis. If the bladder is squeezed on the pubic bone, the relationship between the valve and obstruction can be further shown.

IVU can detect poor renal concentration and hydronephrosis.

Confounding disease of posterior urethral valve

1. Congenital bladder neck contractures are more common in children. Urinary tract obstruction occurs due to bladder neck muscle, fibrous tissue hyperplasia, and chronic inflammation, resulting in narrowing of the bladder neck. Difficulty urinating, urinary retention, bladder ureteral reflux, hydronephrosis, renal dysfunction, and recurrent urinary tract infections. Digital rectal examination that can touch a lump in the bladder and neck. Urinary bladder angiography during urination, showing that the bladder outlet is elevated. The bottom of the bladder is round. Bladder urethroscopy, when the inspection microscope passed the neck of the bladder, there is a sense of tightening, the neck is ring-shaped narrow, the rear lip is levee-shaped, the triangular area is hypertrophic, and the bottom of the bladder is depressed.

2. Congenital sperm hyperplasia sperm spontaneously increases, penetrates into the urethra, and forms a dysuria disorder caused by obstruction. May have dysuria, weak urine line, frequent urination, urinary incontinence, enuresis, renal insufficiency, water and electrolyte disorders and other manifestations. A urethroscopy showed a raised and enlarged sperma. Urinary bladder urethrography during micturition, showing post-urethral filling defect, dilated urethra, and bladder ureteral reflux.

3. Prostatic hyperplasia is a common disease associated with endocrine disorders in older men. Manifestations include lower urinary tract obstruction, difficulty in urination, weak urine flow, thin urinary lines, palpable cysts on the pubic bone, full palpable bladder, palpable enlarged kidneys, and severely affecting renal function. It can be confused with urethral valve in old age. Digital rectal examination can touch the enlarged prostate with smooth surface and rich elasticity, which protrudes into the rectum and the middle groove becomes shallow or disappears. Ultrasound showed that the prostate diameter increased and there was more residual urine. Cystography showed that the bottom of the bladder was elevated, the distance between the lower edge and the pubic bone was widened, and there were trabeculae and diverticula in the bladder wall. Urethral angiography showed that the urethra was extended and enlarged. But the edges are smooth. Cystoscopy showed that the middle lobe of the prostate, both lobe protruded into the cavity, and the bladder wall had a trabecula, a small chamber or the like.

4, urethral stricture is congenital, inflammatory, damaging, iatrogenic and other causes of urethral fibrous tissue proliferation, leading to urethral stenosis. Difficulty urinating, retention of urine, and even secondary infections. Observation of the urethral probe was significantly obstructed in the narrow section. A urethral radiography can show a narrowed segment.

5. Neurogenic bladder is a urinary dysfunction caused by damage to the central or peripheral nerves that control urination. Urinary retention, hydronephrosis, renal dysfunction, and secondary urinary tract infections can occur. Generally has a history of nerve injury caused by trauma or surgery, or a history of systemic diseases such as diabetes, poliomyelitis, or a history of drug application. In addition to dysuria and other symptoms, there are also constipation, fecal incontinence, diminished or disappeared bladder sensation, reduced or lost perineal sensation, decreased or increased anal sphincter tone, and limb paralysis. May have spina bifida, meningocele, malar deformity and other deformities. A cystogram showed a loose tower. Bladder denervation hypersensitivity test was positive.

6, polycystic kidney disease congenital renal polycystic lesions . Mostly bilateral, one third of cases were found in children. Its kidneys are enlarged in nodules and can be found in the upper abdomen, lumbar ridges, and kidney masses. Hypertension and chronic renal failure can occur. However, intermittent intermittent painless gross hematuria occurs. On the excretory urethroplasty film, it can be seen that the shape of the kidney is enlarged, the pelvis and pelvis are compressed and deformed, and they are narrow, prolonged, enlarged, defective or displaced. Ultrasound examination showed multiple fluid dark areas. A radionuclide kidney scan showed multiple defect areas, and the kidney showed impaired renal function.

7. Chronic nephritis is chronic diffuse glomerular damage disease on both sides of the kidney, mainly proteinuria, cast urine, hematuria and edema, hypertension, and impaired renal function. More common in children and young people. Its renal dysfunction can be confused with urethral valves. However, there are no signs of dysuria, and urine protein and cast are unique. Urethral angiography, cystoscopy, and urine flow were normal.

Posterior urethral valve treatment

The main purpose of treatment is to remove the valve. The choice and approach of the surgical method depend on the degree of obstruction and the health status of the child. For patients with mild to moderate obstruction accompanied by mild azotemia, transurethral electrocautery valves can be used with satisfactory results. In a small number of patients, the valve can be destroyed by dilatation of the valve by inserting a urethral catheter, cystoscope, or incision of the urethra through the perineum to insert a urethral probe.

Obstruction seriously causes different degrees of hydronephrosis, children with urinary sepsis and azotemia should be treated with antibiotics, indwelling catheters and correction and electrolyte balance disorders, bladder ureteral reflux and kidney development Ill patients should undergo cystostomy.

Most children with severe hydronephrosis have unsatisfactory cystostomy and valvulotomies because of slow ureteral dilatation and hypertrophy of the bladder triangle, leading to obstruction of the uretero-bladder junction. For these patients, ureterocutaneous fistula is needed to protect renal function and reduce or eliminate hydronephrosis. After hydronephrosis function is improved, valve resection and ureteral reconstruction are performed.

Urinary bypass should be as short as possible. Long-term bladder and upper urinary bypass can cause permanent bladder contracture. Johnston (1979) reported that about 50% of children with urethral valve have bladder ureteral reflux, and bilateral reflux often has a poor prognosis. After the obstruction is resolved, the reflux can disappear naturally in 1/3 of the patients, and 2/3 of the patients need surgery.

Pediatric posterior urethral valve After the obstruction is resolved, antibiotics must be applied to prevent the recurrence of urinary sepsis and urinary tract infections.

Posterior urethral valve prone to disease

Can cause urinary retention, and even bladder ureteral reflux, hydronephrosis of the kidney and ureter, leading to atrophy or cystic change of the renal cortex, and chronic renal failure. Therefore, the urethral valve has great damage to the urinary system with serious consequences. The urethral valve may be combined with cryptorchidism, sperm hypertrophy, or renal hypoplasia.

Prognosis of posterior urethral valve

In order to protect the function of the kidneys and bladder, the best method is early detection. Ultrasound examination of the prenatal fetus should be performed, and the newborn should be carefully examined for physical examination to observe urination and test urine. Children with azotemia and prolonged urinary tract infections have a poor prognosis even after the obstruction has been lifted