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FETAL MEGACYSTIS
– DIAGNOSTIC CRITERIA (1) |
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Longitudinal
bladder diameter |
Outcome |
Normal Bladder |
< 8mm |
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Mild-moderate megacystis |
8-12mm |
Spontaneous
resolution by 20 weeks in most cases |
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Severe megacystis |
> 12mm |
Progressive
obstructive uropathy in all cases |
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Bladder diameter / CRL ratio of 13-22% - Resolution in all cases but
one. |
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Megacystis 7-15 mm |
Megacystis > 15 mm |
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90% resolution |
100% develop obstructive uropathy |
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10% develop obstructive uropathy |
10% abnormal karyotype (trosomy 13 /18) |
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25% abnormal karyotype (trisomy 13/18) |
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First
Trimester Megacystis
Longitudinal diameter of
bladder = 9.6mm Severe obstruction at 18 week
scan. Prune belly at 22 week scan |
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Prevalence 1:1500 45% have an increased nuchal translucency |
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Second and third trimester megacystis |
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REFERENCES |
- Sebire NJ, Von Kaisenberg C, Rubio C et.al. Fetal megacystis at 10-14 weeks gestation. Ultrasound Obstet Gynecol 1996;8:387-390.