← All decks
Radiology
Posterior Urethral Valves
Built from Obstetric Imaging
What’s inside
10 sections · 75 slides
Overview
- What this deck covers
What posterior urethral valves are
A sheet of tissue across the exit from the bladder
- The route urine takes before birth
- A membrane across the exit
- Only boys, and usually nothing else
- How common it is
- 1:3000
- Where the valves come from
- The real damage is back-pressure
- Two dangers, not one
- Why low fluid wrecks the lungs
What it looks like on ultrasound
A big bladder, a thick wall and a keyhole
- The first sign is a big bladder
- What bladder size tells you
- Enlarged fetal bladder at 13 and 16 weeks
- A wall that grows thick
- Colour Doppler outlining a thick-walled fetal bladder
- The keyhole sign
- How much the keyhole sign proves
- Keyhole sign in an 18-week fetus
- “
Fluid and kidneys decide the outcome
What the scan says about the future
- Amniotic fluid is the prognosis
- Normal fluid now is not a normal kidney later
- 97%
- What the kidneys look like
- Small bright kidneys with dilated tortuous ureters
- Cystic dysplasia: the kidney gives up
- Cystic change appearing in the kidney between 20 and 26 weeks
- Dilated renal pelves and calyces at 20 weeks
- Diffuse cortical cysts by 26 weeks
- Wide pelvis, fat ureters: weak predictors
- When the system springs a leak
- Urinary ascites at 25 weeks
- Bladder wall measuring 6 mm
Look-alikes and the role of MRI
What else makes a fetal bladder look like this
- When ultrasound runs out of road
- Fluid-filled pelvic structures on ultrasound and MRI
- Look-alikes in the urethra itself
- Look-alikes beyond the urethra
Staging the blockage
Four questions that separate mild from hopeless
- Why stage it at all
- Lower Urinary Tract Obstruction Staging System
- The staging grid at a glance
- The four stages in words
- The two ends of the range
Who is offered treatment before birth
Four gates, then a bladder tap
- Gate one: is there anything to gain
- Gate two: is it truly isolated
- Gate three: the fetus must be male
- Getting to a treatment decision
- The bladder tap: vesicocentesis
- Why the urine chemistry says anything
- Which analytes are measured
- Favorable Urinary Analyte Values Based on Serial Vesicocenteses at 18 to 30 Weeks
- Tapping more than once
- What the answer changes
The two fetal procedures
A drain into the fluid, or a laser to the valve
- Two ways to relieve the block
- How a shunt is placed
- Double-pigtail shunt draining the fetal bladder at 21 weeks
- What a shunt does and does not do
- Shunt complications
- The randomised trial of shunting
- Fetal cystoscopy: treating the valve itself
- Cystoscopy: risks and results
- Shunt against scope, side by side
- The multicentre comparison
After delivery, and for life
Confirming the valve, removing it, then watching
- The first hours after birth
- Removing the valve
- Five questions asked for life
- The long-term picture
- ~30%
Taking it away
What to tell the referring clinician, and the family
- What the referring clinician needs to know
- When to think about fetal treatment
- Key points
- Suggested readings
- References
- References (continued)
- References (continued)
- References (continued)
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition