Antenatal hydronephrosis. What has changed? Dr Nick Plant Consultant Paediatric Nephrologist Royal Manchester Children’s Hospital @nephrology_RMCH RMCH 30 th June 2017
Antenatal hydronephrosis.
What has changed?
Dr Nick Plant
Consultant Paediatric Nephrologist
Royal Manchester Children’s Hospital
@nephrology_RMCHRMCH 30th June 2017
A good year on Twitter?
A good year on Twitter?
Overview
� The extent of the problem
� Aetiology
� Algorithms
� PUJO
� Summary
The extent of the problem
� Antenatal hydronephrosis (ANH) is defined as
“Dilatation of antero-posterior (AP) diameter of
renal pelvis ≥7mm at 18-20 weeks gestation”
The extent of the problem
� Antenatal hydronephrosis (ANH) is defined as “Dilatation of antero-posterior (AP) diameter of renal pelvis ≥7mm at 18-20 weeks gestation”…
� …or ≥10mm from 32 weeks onwards� The prevalence ranges from 0.6 - 4.5%� Bilateral in 17 – 54%� Male:female = 1:1, 2:1 or 5:1� 50-70% are transient or physiological � It is important to identify infants with significant
illness that require long-term follow up and/or surgery. Parental anxiety.
Aetiology
� 1. Nguyen H.T., Benson C.B., et al, 2014.
Muitldisciplinary consensus on the
classification of prenatal and postnatal
urinary tract dilatation. Journal of pediatric
urology, 10(6), pp.982-998.
Grading
Grading
� Evaluates:
� The dilatation of the renal pelvis(es)
� Distinguish between central (major) &
peripheral (minor) calyceal dilation
� Parenchymal thickness
Grade 0: no dilation (not shown). Grade 1: renal pelvis is only visualized. Grade 2: renal pelvis as well
as a few, but not all, calyces are visualized. Grade 3: virtually all calyces are visualized. Grade 4:
similar to Grade 3, but when compared with the normal contralateral kidney, there is parenchymal
thinning.
Mild – moderate risk factors
•Unilateral hydronephrosis
•Unilateral hydronephrosis ≥ 7 mm but ≤ 10 mm with single kidney
•Unilateral multicystic dysplastic kidney with normal contralateral kidney
•Unilateral renal dysplasia/hypoplasia with normal contralateral kidney
•Bilateral hydronephrosis ≥ 7 mm but ≤ 10 mm
•Single kidney with normal parenchyma and no dilatation
•Non obstructing ureterocele
•Other kidney abnormality (e.g. echogenic kidney, duplex system,
horseshoe kidney) with normal liquor volume
Postnatal management:
mild - moderate risk
•Antibiotic prophylaxis is not recommended in mild to moderate risk
features, except for those with family history of vesicoureteric reflux
(VUR). If so, commence trimethoprim 2mg/kg PO nocte
•In those requiring follow up scans, it is recommended that the first
post-natal USS be delayed for at least 48 h after birth (because of
reduced urine output in the first 48 hours), but most follow up scans
can be organised for between1-4 weeks
•All newborns with history of antenatal hydronephrosis and
resolution prenatally, do not need further scans postnatally and can
be discharged home safely
Severe risk factors
• Bilateral hydronephrosis ≥ 10 mm• Suspected bladder outlet obstruction (PUV/urethral stenosis or stricture)• Unilateral hydronephrosis ≥ 10 mm in fetus with a single kidney• Renal parenchymal abnormalities bilaterally
- Polycystic kidneys - Congenital nephrotic syndrome- Echogenic kidneys associated with oligohydramnios
Postnatal management:
Severe risk factors
•Commence babies on trimethoprim 2mg/kg PO nocte as
prophylaxis. (NB this indication is unlicensed in children under 6
weeks.)
•In neonates with bilateral hydronephrosis >10 mm, presence of
oligohydramnios or suspicion of posterior urethral valves, post-
natal US should be performed within 3 days birth.
•Micturating cystourethrogram (MCUG) must be performed in
patients with bilateral hydronephrosis >10 mm or bilateral
ureteric dilatation.
•In the absence of bladder outlet obstruction, MCUG can be
performed at 4-6 weeks of age.
•Infants with lower tract obstruction should be immediately
referred to urology for appropriate intervention.
Antenatal Scanning
18-20 week scan
Hydronephrosis ≥ 7mm
Bilateral hydronephrosis ≥
10mm or associated with a single kidney.
Follow bilateral ANH protocol
Repeat scan at 32 weeks
Bilateral ≥ 10mm.Follow bilateral ANH
protocol
<10mm and unilateral.Discharge with no
postnatal investigation
≥10mm and unilateral.Follow unilateral ANH
protocol
Any evidence of ureteric dilatation.
Follow bilateral ANH protocol
Repeat scan at 32 weeks to ensure not bilateral or worsening
Postnatal scanning:
Unilateral hydronephrosis
Postnatal scanning:Bilateral hydronephrosis
Notes
These are high risk groups and bladder outlet obstruction
should be excluded
*There is a recognised (1-2%) risk of introducing urinary
infection at the time of a MCUG. It is recommended that
prophylatic antibiotic therapy is increased to therapeutic
doses for a 48 hour period around the procedure.
neonate: initially 3mg/kg as a single dose then 2mg/kg BD
for 48 hours
child 1month to 12 yrs: 4mg/kg BD for 48 hours
PUJO
� AP >20mm ‘may well’ be associated
with deterioration in renal function
� >30mm = 60% chance of deterioration
� Pelvis can enlarge significantly before
function falls
� The greater the calyceal dilatation, the
greater the risk of deterioration
PUJO
� Consider pyeloplasty if:
� Progressive pelvic dilatation
� Symptoms
� Reduced function on MAG3
� TPD >30mm
Summary
� What’s changed?
� Minor changes to AP diameter limits
� Therefore, fewer investigations
� Earlier discharge from follow up
� Less reliance on MCUGs
� Less prophylactic antibiotics required
A new use for sildenafil?
Finally… Spanish NF1