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Posterior Urethral Valves Posterior Urethral Valves
by Kimberly Allen, RN Posterior urethral valves are abnormal membranes that develop at the end of the urethra near the urinary bladder obstructing the... Posterior Urethral Valves

by Kimberly Allen, RN

Posterior urethral valves are abnormal membranes that develop at the end of the urethra near the urinary bladder obstructing the urine flow.  Posterior urethral valve obstruction or PUV occurs exclusively in boys and is the most common cause of urinary obstruction in male newborns, occurring in approximately 1 out of 5,000 male newborns.  PUV is a congenital disorder which means it is present at birth.  PUV is not passed from parent to child like a genetic disorder.  However, there have been some cases where twins and/or siblings are born with PUV which suggests there may be a genetic component.

Although the exact cause of PUV is unknown, doctors believe the malformation occurs early in fetal development and have a theory on the cause.  Normal urethral valves are very small, the belief is that during the development of the male fetus his body sends a signal that either tells the tissue to stop growing or helps it to decrease in size.  In boys with PUV, the signal is never sent or received and is believed to be missing which in turn allows the tissue to continue to grow.  Also, because PUV develops in the early stages of fetal development the entire urinary tract  including the kidneys, bladder and ureters are affected.  The back up of urine can lead to these organs becoming engorged with urine causing them to swell.  This in turn leads to cell and tissue damage in the urinary tract.  For this reason many boys born with PUV also have other congenital urinary tract problems including renal hypoplasia and renal dysplasia.PUV

There are three types of PUV categorized as PUV I, II, and III.  However, regardless of what type of PUV your son may have the results is the same, there is an obstruction preventing the urinary bladder from emptying.  the severity of the obstruction determines the severity of the symptoms.  In the past PUV could not be detected until after birth but today with ultra sound and other radiological technology it can frequently be detected while in utero.  Because today most pregnant women receive an ultra sound at least twice during their pregnancy, once around 10-12 weeks gestation and the second around 20 weeks gestation, which is an anomaly scan, approximately 2/3 of babies with PUV are found prenatally.  There are certain symptoms that will appear in the ultra sound that indicate your son may have PUV including a swollen and thick walled bladder as well as swollen ureters and kidneys.  Another key indicator that the baby has PUV is if the mother suffers from oligohydramnios, which is insufficient amniotic fluid.  If the obstruction is mild and there are no indicators seen on the ultra sound there are symptoms that may manifest after birth including multiple urinary tract infections which is not only uncommon in children under 5 years of age it is almost never seen in boys at any age.  So if your infant or toddler develops recurrent urinary tract infections they should be investigated further.  Other symptoms your son may experience include difficult and painful urination with a weak urine stream as well as urinary frequency.  Older children that have been toilet trained may wet their pants or their bed.  Most boys with PUV also demonstrate poor weight gain.  In cases of severe PUV your child may experience respiratory distress and.or severe swelling of the kidneys or hydronephrosis as well as bladder dysfunction.

Treatment for PUV depends on a number of factors including the severity of the obstruction as well as your child’s age, general health and medical history.  Your doctor will also consider your child’s ability to tolerate certain procedures, therapies and medications as well as the anticipated course of the anomality and your personal preference and opinion.  All treatment will first focus on relieving any symptoms your child is experiencing, for example if he has a urinary tract infection or electrolyte imbalance these will be treated first.  Then your doctor may recommend a procedure called endoscopic abilation.  In this procedure the doctor inserts an endoscope into the urethra and assesses the obstruction as well as remove the obstructing membranes.  For those that are discovered in utero, doctors can intervene with vesico – amniotic shunting or serial vesicocentesis which is believed to improve survival and preserve renal function.

Kimberly Allen is a registered nurse with an AND in nursing. She has worked in ACF, LCF and psychiatric facilities, although she spent most of her career as a home health expert. She is now a regular contributor to, dispensing advice and knowledge about medical issues and questions. You can reach her with any comments or questions at