A 30-week obstetric ultrasound shows severe oligohydramnios (AFI 2 cm), absent kidneys in the renal fossa, bilateral adrenal hyperplasia appearing to fill the renal fossa, and absent bladder filling. What is this condition?
- A Potter sequence due to bilateral renal agenesis ✓
- B Multicystic dysplastic kidney (MCDK)
- C Bilateral pelviureteric junction obstruction
- D Prune belly syndrome
Explanation
Potter sequence (oligohydramnios sequence) results from bilateral renal agenesis (BRA) — absence of both kidneys leads to severe oligohydramnios due to absent fetal urine production, which in turn causes pulmonary hypoplasia (the primary cause of death), limb contractures, flat facies, and anomalies from mechanical compression. The adrenal glands, without kidneys to displace them, occupy the renal fossae and appear 'lying down' (adrenal lying down sign). MCDK shows multiple non-communicating cysts replacing a kidney. Prune belly syndrome shows a distended bladder and abdominal laxity.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.