Fetal Renal Anomaly (Cystic/Dysplastic)

Step-by-step decision

Choose step by step as prompted; reaching an endpoint gives the management recommendation. You can go back a step or restart anytime.

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Full pathway

1. [Decision] Uni/bilateral + fluid + morphology
   Uni/bilateral + amniotic fluid (renal function marker) + morphology? (Amniotic fluid = renal function marker. First determine uni/bilateral + fluid + contralateral kidney + bladder. Bilateral/anhydramnios → pulmonary hypoplasia (lethal).)
   • Unilateral MCDK (multiple non-communicating cysts), contralateral normal, normal fluid → Unilateral MCDK · good prognosis
   • Bilateral large echogenic kidneys + oligohydramnios (suspect ARPKD) or familial (ADPKD) → Bilateral large echogenic kidneys · ARPKD vs ADPKD
   • Bilateral cystic/dysplastic or bilateral renal agenesis, oligohydramnios/anhydramnios → Bilateral/renal agenesis · lethal
2. [End] Unilateral MCDK · good prognosis
   Unilateral MCDK (non-communicating cysts, loss of reniform shape), contralateral normal, normal fluid: good prognosis (contralateral compensatory hypertrophy, ~60% involute); focus on the contralateral kidney (30–50% abnormal, e.g. VUR/UPJ) + bladder + fluid; extra-renal anomalies ~25% → karyotype; postnatal nephrology/urology follow-up + blood pressure monitoring.
3. [End] Bilateral large echogenic kidneys · ARPKD vs ADPKD
   Bilateral large echogenic kidneys — ARPKD (oligohydramnios, hepatic fibrosis, PKHD1, poor prognosis) vs ADPKD (family history, PKD1/2, normal/polyhydramnios): detailed fluid/liver/family history + genetics; ARPKD with oligohydramnios has high pulmonary hypoplasia risk, needs counselling; serial monitoring of kidney size and fluid.
4. [End] Bilateral/renal agenesis · lethal
   Bilateral MCDK/dysplasia or bilateral renal agenesis (Potter), oligohydramnios/anhydramnios: pulmonary hypoplasia + renal failure = lethal (bilateral renal agenesis has no bladder, no fluid); karyotype/microarray + exome + check syndromes (Meckel-Gruber, etc.); multidisciplinary + genetic counselling, full informed consent.

Source guidelines & references

• Fetal multicystic dysplastic kidney and renal anomalies (SMFM Consult #4, 2021; ARPKD/ADPKD)

This pathway is our own synthesis of the decision logic in the guidelines above (not the guideline verbatim); thresholds and workflows change as guidelines update — in practice follow the latest guideline, your institution's protocol and the individual patient.

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