|
What are posterior urethral valves?
The urethra is a tube that allows the urine from the urinary bladder to flow out . It is the lowest part of the urinary tract.
Some boys are born with a membrane, like a curtain across the urethra. This slows down the urine flowing out of the bladder. This membrane is called a posterior urethral valve (PU Valve).
|
|
|
What happens when there are PU Valves?
The bladder is a muscular sac that must contract when urine is to be voided. Whenthere is resistance to urine flowing out, as in a PU Valve, the bladder is constantly working against resistance. It has to work harder, and this causes the muscle to hypertrophy, or become thicker. This is analogous to what happens when a person works out at a gym.
Unfortunately, in the bladder, the thicker muscle reduces the elasticity of the bladder. The bladder cannot expand as it usually does when storing urine. It generates very high pressures within, which get transmitted to the kidneys. The kidneys, in turn get swollen and this can affect their functioning. |
|
|
How will I know that my son has PU Valves?
These days, most babies with PU Valves are diagnosed by ultrasounds done during pregnancy. Those not picked up before birth typically have straining while passing urine. The urine stream is not good and the child passes urine in drops.
Some babies will have valves diagnosed because they develop a urinary tract infection. |
|
|
What treatment is required?
The usual treatment is done by using a cystoscope. This is an instrument that allow a surgeon to look into the urethra and perform some operations without making external cuts. Using a cystoscope, the valves are cut to allow the urine to flow freely. In some unusual situations, other methods may be used to make sure that no urine remains collected in the body, and that the kidneys can freely drain out the urine produced. |
|
|
If the valves are cut, is my son cured?
PU Valves may have already affected the kidney to an extent that is irreversible. Your son will need regular checks by a surgeon and a children’s kidney specialist, to maximize whatever function the kidneys have. Unfortunately, some children may be affected severly enough to need very active management of their renal disease. Some children may have an irreversible change in the ability of the bladder to function and empty well.
So even after the valves are destroyed and the urine flows freely, a strict follow-up is needed for many years.
|
MCU shows that the bladder (blue dot) leads to a very dilated posterior urethra (yellow arrow), and the urine stream (red arrow) is very fine. The urine is “dammed-up” behind the valves (green arrow) |
|
|
|