Renal: Posterior Urethral Valves Flashcards
It is a condition found only in…
Boys
Describe what it is
An abnormal, obstructing membrane in the posterior urethra that develops in utero
What can be noted on antenatal USS?
Bilateral hydronephrosis
Poor renal growth, with reduced renal cortex
Decreased amniotic fluid volume
At worst, what can this result in?
A dysplastic kidney - small, poorly functioning and may contain cysts (in most severe cases Potter syndrome is present)
Declining amniotic fluid can lead to…
Pulmonary hypoplasia
Why might mild outflow obstruction not be evident in first few days of life?
The newborn kidney has low GFR and especially low if preterm
What investigations can be done?
USS - good at visualising urinary tract dilatation Micturating cystourethrogram (MCUG) - can visualise bladder and urethral anatomy, can detect VUR and obstruction
What is a typical finding on MCUG?
Bilateral vesicouretic reflux
Small, thicker bladder
Dilated posterior urethra
How can it be managed initially after birth?
Urethral catheter
Prophylactic antibiotics
What is the definitive treatment?
Ablation surgery via cystoscopy
Is it thought to be an inherited condition?
No
In less severe cases, it is only picked up when child is older, when symptoms develop such as…
Difficulty passing urine Weak stream Enlarged bladder - palpable mass UTIs Increased frequency Dribbling of urine after urinating Day time wetting in toilet trained children
What does MCUG involve?
Inserting urinary catheter into bladder and injecting contrast dye through it. This helps to show up the urethra and identify blockages.
Can also be used to test for VUR
What is cystoscopy?
Inserting a small tube attached to a camera into the bladder through urethra
What tests should also be done?
Kidney function tests - urea and electrolytes
