Ask The Expert Session: Antenatal Hydronephrosis

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Ask The Expert SessionAntenatal Hydronephrosis

• Paul Roy

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ANTENATAL
HYDRONEPHROSIS
A/Professor L Paul Roy Paediatric
Nephrologist Childrens Hospital Westmead Royal
Prince Alfred Hospital, Camperdown
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Autosomal Recessive Polycystic Kidney
Disease ( NB William Garrett
) Garrett WJ, Grunwald G, Robinson DE Prenatal
diagnosis of fetal polycystic kidney by
ultrasound. Aust NZ J Obstset Gynaecol. 1970,
107-9
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WHAT CAN ULTRASOUND TELL ME ABOUT THE FOETAL
KIDNEY? Is the drainage system dilated? Is it
of normal size and position? Is the parenchyma
normal? Does it make a normal amount of urine?
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Antenatal Diagnosis Origins of interest
UTI is common VUR appears more common in children
with UTI than in the general population Recurrence
of UTI more common in children with VUR 5 of
children with VUR UTI ultimately have some
renal scarring 5 of the 5 above develop renal
failure As a result- Screen for VUR before
UTI Prevent UTI - ?evidence -gt Trial 2 Prevent
renal scarring - ?evidence -gt Trial 1
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ANTENATAL RENAL FUNCTION
Urine Output 20 weeks 2ml/hour
39 weeks 26 ml/hour Favourable
Urine Values Sodium lt 100
mmol/L Chloride lt 90
mmol/L Osmolality lt 200 mOsm/kg ? 2
microglobulin lt 500 mmol/L Total protein
lt 200 mg /L Sensitivity/specificity of these
markers 40-100 in various
studies POST NATAL GFR - ml/min/1.73m2 Week 1 -
40 week 4 - 50 week 6 - 70
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PELVICALYCEAL DIMENSIONS
Grignon 1986 Anteroposterior distance Gd 1
lt10mm Gd 2 10-15 mm
Normal calyces Gd 3 gt15 mm Slight
Dilatation calyces Gd 4 gt15 mm Moderate
dilatation Gd 5 gt15 mm Severe dilatation
atrophic cortex
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The Natural History of Renal Pelvicalyceal
Dilatation Detected on Antenatal Ultrasoundde
Soysa SR, Sureshkumar P, Knight JF, Boogert T and
Roy LP
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Background

• Increasingly accurate real time ultrasound (US)
  is detecting antenatal anomalies of uncertain
  clinical significance.
• The prevalence of renal pelvic dilatation (RPD)
  detected antenatally 1-2 of screened
  pregnancies.
• Does this indicate the presence of obstruction
  (PUJO) or reflux (VUR)? What are the outcomes for
  those with persisting isolated dilatation?
• Can we predict which require intervention vs
  careful follow-up?

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Aims

• To determine
• the relationship between degree of dilatation and
  clinical outcome at 1 year.
• the proportion of this population with PUJO and
  VUR and the incidence of urinary tract infection
  (UTI).
• the optimum timing of antenatal and postnatal US
  for the detection of renal tract pathology.
• the optimum postnatal investigations to be used
  in evaluating this population.

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Methods

• Study population retrospective cohort of 131
  dilated systems ( 82 foetuses), born at term
  between Oct.92 and Dec.95. No family history of
  renal disease.
• Isolated RPD /gt 4mm max. anteroposterior (AP)
  diameter at 16 week US or later.
• Postnatal evaluation
• a) renal US at 5-7 days of age,
• b) MCU at 0-2 weeks of age.

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Methods (contd)

• Those with no abnormality other than persisting
  RPD had further US at 6 and 12 months of age.
• Other investigations were conducted where
  clinically indicated (Eg MAG III scan, DTPA
  scan).

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1 year Outcomes by max. antenatal RPD (n121)
Excludes 10 units lost to follow-up (7), under
investigation (1) and antenatal measurements not
known (2).
RPD by Pathology (n12)
VUR
Primary megaureter
Duplex
4-lt7mm
PUJ
7-lt10mm
PUJVUR
PUJ
gt/10mm
VUR
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Results Validity of US

• Of 6 renal units reported as normal on postnatal
  US
• VUR (Grades II-IV) 3 PUJO 1. Other
  anatomical variants 2 diagnosed up to 1 year of
  age. These 2 children were clinically well and
  would not have been diagnosed if not for
  follow-up as part of the cohort.
• Postnatal US has
• sensitivity 62.5 and specificity 66.7 for
  VUR
• sensitivity 60.7 and specificity 62.1 for
  PUJO.

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Conclusions

• Degree of isolated antenatal RPD correlated
  poorly with 1 year clinical and radiological
  outcome.
• The proportion of patients with renal tract
  pathology was low.
• Lesser degrees of dilatation were detected with
  equal frequency early and later in pregnancy.
• Postnatal US alone is inadequate in the
  evaluation of VUR and PUJO.
• Chemoprophylaxis may not be indicated in isolated
  dilatation.

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Conclusions

• This study casts doubt on the value of isolated
  RPD as an indication for postnatal screening.
• Consider parental anxiety, risks of
  investigations.
• Larger series required to define the
  characteristics of physiological dilatation.

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A Prospective study- 1
Jaswon et al Arch Dis Child (1999) 80F135
Childrens Hospital Michigan 7000 deliveries
screened over 26 months Criterion Pelvic
anteroposterior dimension gt5 mm Post Natal
Investigation 2-4 weeks Ultrasound 3-4 months
MCUG No Reflux -- 5-10 mm US at 1
year -- gt10 mm MAG 3 Renogram
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A Prospective Study 2
139 Enrolled - 1.98 104 studied ( degree of
dilatation of those whose parents declined not
stated) VUR 23/104 (male predominance) 22 No
correlation between degree of reflux and
antenatal pelvic dimensions. DMSA No
scars Idiopathic dilatation
ie MCUG and MAG3 Normal
8/104 7 PUJ 4/104
3 managed conservatively 1
pyeloplasty 18 month decreased function ?1
Side or both Renal Dysplasia 4/104 Conclusion
Investigate babies with Antenatal APgt5mm ?
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Vesico ureteric reflux Isolated -Post natal
A selected reference from GOS Yeung et al Brit J
Urol (1997) 80319 155 consecutive referred
infants found to have reflux due to antenatal
diagnosis hydronephrosis 117 boys - 75 38 girls
- 17 Higher grades of reflux more common in
boys than girls 55 vs 22 63 infants ( 56 boys
and 7 girls ) had abnormal kidneys (27 had had
a UTI by the time they were studied?) Girls tend
to have mild reflux and normal kidneys
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Personal Experience!
Children referred with antenatal diagnosis of
hydronephrosis in a 12 year period Total Number
209 Hydronephrosis ( not otherwise
defined) 103 Vesicoureteric reflux
10 Pelviureteric junction
obstruction 23 Multicystic
dysplastic kidney
16 Polycystic Kidney(AR)
(1) Renal Dysplasia
4 Normal child
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What do I do?
1. Antenatal Dilatation lt 10mm - Normal kidneys
and bladder Post natal US at 2 weeks lt10mm and
normal kidneys - repeat 6 months gt10mm - MAG
3 scan at 4-6 weeks
Prophylaxis 2.Antenatal dilatation gt10 mm Post
natal US 3-4 weeks and MAG 3 radioisotope scan at
4-6 weeks
Prophylaxis 3. Individualise for more complex
situations