1 Unique way to Recognise Posterior Urethral Valve in Newborn

Posterior urethral valve in newborn is a serious congenital urinary disease in male babies. To know this congenital disease, it is important to know about the urinary system of the body.

The urinary system is made up of kidneys, ureters, bladders, urethra.

  • Kidney – Both kidney are Bean shaped organs. The kidneys filter the blood in the body and expel excess water and waste products in the form of the urine. Usually our body has two kidneys. The kidneys are located at the back of the abdomen in the lumber region.
  • Ureter – There is a tube called ureter to carry urine from the kidneys. The length of this tube is 25 cm. This tube is attached to the bladder below.
  • Bladder– The bladder is a sac that collects urine. Bladder is located in pelvic area.
  • Urethra– Urethra is also a type of tube that carry urine accumulated in the bladder out of the body.

So now Let’s learn more about the posterior urethral valve in newborn.

What is a posterior urethral valve in newborn?

The posterior urethral valve is the fleshy membrane at the back of the urethra. This membrane is formed in the first few months while the baby is still in the mother’s womb. Posterior urethral valve obstruction is seen only in male babies.

The posterior urethral valve obstructs urination while the baby is in the mother’s womb. This causes swelling in the urinary tract. Therefore, it has adverse effects on the kidneys, ureters and bladder due to retension of urine.

Another problem is that water from the mother’s womb is made up of the baby’s urine from the fifth month of pregnancy. The posterior urethral valve prevents the baby from urinating, resulting in decrease in water level of womb which is known as oligohydramnios.  This also affect the development of the baby’s lungs. Therefore, oligohydraminos is often seen in the mother’s pre natal sonography before the baby is born.

What causes posterior urethral valve in newborn?

The cause of posterior urethral valve formation is not clear but posterior urethral valve is seen in twins, father and son. So sometimes the cause may be heredity. About one in 5,000 babies is born with the posterior urethral valve.

What are the symptoms of posterior urethral valve in newborn?

The posterior urethral valve causes swelling in the baby’s kidneys while the baby is in the mothers womb. It is called antenatal hydronephrosis.

The following symptoms appear after birth

  • Frequent urinary tract infections – The posterior urethral valve causes the baby’s urine to fill the bladder. Due to retention of urine in bladder, there will form urinary tract infection due to which baby has a high fever.
  • Difficulty urinating and dripping urine.
  • As the urine stays in the bladder, it reaches the kidneys again through the ureter and has a serious effect on the kidneys. This condition is called vasicoureteric reflux.
  • As the urine fills the bladder, the baby’s blood pressure also rises.
  • As it has serious effects on the kidneys, it has an adverse effect on the growth and development of the baby.
  • The posterior urethral valve causes oligohydramnios when the baby is in the mother’s womb, causing severe damage to the baby’s lungs and if the lungs do not grow, the baby’s life is in danger.

How posterior urethral valve in newborn is diagnosed?

When the mother’s sonography is done while the baby is in the womb before birth, it is possible to understand the amount of water in the mother’s womb which is mostly formed by the baby’s urine. Posterior urethral valve does not diagnosed on sonography but due to following posterior urethral valve can be diagnosed.

The baby’s kidneys, ureters, bladder are swollen. This makes you understand that there is something obstructing the urinary tract.

There is very little water in the mother’s womb due to obstruction of the baby’s urinary tract or impaired renal function. It is better to consult a pediatric surgeon for antenatal counselling.

True diagnosis of posterior urethral valve can be done after birth. The following tests are done on the baby.

  •     Abdominal sonography – Sonography of the baby shows swelling of the kidneys.
  •     MCUG – An X-ray is taken of the baby’s urine to find out how the baby’s urine is coming out of the baby’s body.
  •     DMSA scan – is done to check the function of the kidneys. It is done after giving dye into the baby’s blood intravenously And images of the urinary system are taken.
  •     Blood tests – A baby’s blood tests show how well the kidneys are fuctioning.
  •     Urine test – A urine test is done to see if there is any infection in the urine.

What is the treatment of posterior urethral valve in newborn?

The first treatment is based on the baby’s condition. The most important treatment is to remove the obstruction in the baby’s urinary tract. But before that, it is also important to make the baby’s condition is stable.

The first step in removing the baby’s symptoms is to insert a tube into the baby’s urinary tract so that the baby’s full urine can be expelled from urinary bladder.

If the baby’s body is dehydrated and baby have electrolyte imbalance, then first it is normalised with the help of IV fluids and if the baby has a urinary tract infection, antibiotics are given intravenously.

Endoscopic ablation of posterior urethral valve – Once the baby’s condition is stable, the membrane of the baby’s urinary tract is burned, which clears the baby’s urinary tract and reduces the amount of urine in the bladder.

Although the baby’s symptoms subside after the baby’s membrane burns, it is very important to follow up such babies to a urologist for frequent checkups.

What are the complications of posterior urethral valve in newborn?

In 30% of babies with posterior urethral valve, there may be some kidney failure. If the operation is performed at a young age, the incidence of this complication is very low.

Some babies have swelling on the kidneys and some babies have urine flowing from the bladder into the ureter causing vasicoureteric reflux. The incidence gets lower in 50% of babies who have had surgery And the remaining 50% of babies can have renal problem. It may require a separate operation. This is called ureteric reimplantation.

Does the posterior urethral valve seen in girls?

No. The posterior urethral valve is not seen in girls.

Ref – UCSF

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