Introduction
Posterior urethral valves were first described by Hugh Hampton Young in 1919. It is observed at various levels of severity and is the most common cause of bladder obstructions in males. Its severity can range from a stage incompatible with postnatal life to conditions that have so little effect that they would not show up until far later in life. This article deals with the advances in diagnosis and management of the condition.
What Is Posterior Urethral Valve?
It is a rare condition seen only in male infants-assigned infants at birth. Studies show that it is seen among one in five thousand babies. The condition is also called Congenital Obstructive (or obstructing) Posterior Urethral Membrane (COPUM). Babies who are born with the condition have an additional fold in the urethra. This prevents the urine from flowing properly through the bladder. The urethra drains urine from the bladder outside the human body.
The urethral valves have very small openings in children with this condition. This prevents the urine from being completely removed from the body. The incomplete removal of urine can cause damage to the urinary tract. The organs can get swollen due to the accumulation of urine in the tissues. If left untreated, it can cause damage to the other organs, which can persist even after treatment.
How Is Posterior Urethral Valve Diagnosed?
When there is an obstruction in the urine flow, it accumulates at the site before the blockage. This can cause dilation of the urinary tract, as seen in the ultrasound scans done during pregnancy. If the condition is not identified in pregnancy, it can show the following signs after birth:
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No urine output.
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Low stream of urine.
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Poor feeding.
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Frequent urinary tract infections.
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Swollen abdomen due to distended bladder or kidneys.
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Difficulty in passing urine.
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Bed-wetting in older children if left untreated.
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Poor weight gain.
The diagnostic tests done can include:
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Ultrasound: Distension in the bladder, ureters, kidneys, and upper part of the urethra can be seen in an ultrasound done during pregnancy. The area of obstruction can also be seen in the ultrasound.
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Blood Tests: Blood tests are done to check the functioning of the kidney.
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Micturating Cystourethogram (MCU): This is the test done to confirm the condition. A small tube is placed in the bladder through the urethra. A contrast material is injected into the tube to view the outline of the urethra. An X-ray will help to know any abnormality of the bladder, back-flow of urine, or any abnormality of the shape of the bladder.
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Cystoscopy: It is a therapeutic and diagnostic approach for the condition. As it is a surgical procedure, it is done under anesthesia. A small telescope is placed in the ureter to identify and treat the obstruction in a single procedure.
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Biochemical diagnosis: The fetal urinary electrolytes are the only biomarkers studied as an in-utero indicator of renal functioning and long-term function predictor. Despite much literature favoring the utilization of fetal urinary electrolytes as an indicator of renal functioning, a recent meta-study showed no such predictive values. Proteomic analysis (a complete study of the functioning and protein structure) of children with posterior urethral valves showed severe collagen degradation products, which could predict the severity of renal obstruction.
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Genetic Studies: Despite many advancements in diagnosing the condition, genetic studies require more research. The association of the condition with genetic disorders like trisomy 21 has been found, but a more extensive study is required to get detailed data.
How Is Posterior Urethral Valve Treated?
1. Newborn:
Removal of the urinary obstruction is the first step in treating the condition in a newborn. This is done by placing a urethral catheter. Cystoscopic valve ablation or vesicostomy (surgical removal of the valves) can be done later. In very rare cases, the urethral catheter can not be placed. This is mainly because of the swollen neck of the bladder due to the accumulation of urine. These babies require cystoscopy under anesthesia to do the procedure. Care of a newborn with the condition requires expertise and proper instrumentation set-up. Placing a urethral catheter and moving the baby to a care center with the required facility as soon as possible is recommended in a place where these services are not available.
2. Older Children:
Caring for older children also requires expertise and facilities. Radiologic and urodynamic evaluation at regular periods is required to monitor the changes in the upper urinary tract and bladder. They might require care over their entire lifetime.
3. Vesicostomy: A surgical procedure done to make an opening in the bladder to outside the body in order to remove the accumulated urine is called vesicostomy. This helps to prevent further infection and damage to the kidney. This is usually done in very small or sick babies.
4. Endoscopic Valve Ablation: This is a surgical procedure where the valves or the excessive tissues are trimmed. This is done in stable babies who can be treated under anesthesia and radiological imaging. It is usually done using a laser. It is important to use thin instruments to prevent urethral stricture in the future. Regular monitoring of the residual volume (amount of urine left in the bladder after voiding) is required after the procedure.
5. Treatment of Persistent Hydronephrosis: The hydronephrosis (accumulation of urine in the kidneys causing them to become swollen) that persists after endoscopic valve ablation and bladder drainage is treated by temporary upper urinary diversion. However, this procedure has shown no long-term results in preventing renal failure. Another disadvantage of the procedure is the reduction of bladder capacity. However, these are rare scenarios.
How Is the Prognosis of Posterior Urethral Valve After Treatment?
According to the recorded literature, the prognosis of the condition earlier was 50 percent. However, the prognosis is improving with advancements in diagnostic tools and treatment modalities.
Conclusion
The posterior urethral valve is a rare condition in which the urine flow is obstructed in males. It is seen in varying severity, depending on the level of obstruction. The treatment of the condition remains a challenge and requires much research. It requires lifetime monitoring, from the prenatal period to the adulthood.
