obstructive cystic renal dysplasia
Obstructive cystic renal dysplasia, or Potter type IV cystic renal disease, is a potential complication that can occur from prolonged obstruction of the bladder outlet or urethra during gestation.
Ureteric obstruction during active nephrogenesis results in cystic renal dysplasia; the earlier and longer the obstruction the more severe the histopathological changes of dysplasia .
Any obstructive renal tract pathology distally involving the renal tract can be a potential cause which include:
- posterior urethral valves
- urethral agenesis
- Duplex collecting system with obstructing ureterocoele
- congenital vesicoureteric junction obstruction
Associated anomalies may be present in up to 50% of cases can include:
- VACTERL association
- congenital heart disease
- CNS abnormalities
- congenital gastrointestinal malformations
The kidneys are usually normal to small in size with highly echogenic cortices, loss of cortico-medullary differentiation, and scattered cysts (usually smaller than those seen with multicystic dysplastic kidneys) . The reniform shape is often preserved until late in the disease.
General differential considerations include:
- multicystic dysplastic kidneys: no distal obstruction
- Meckel-Gruber syndrome: has occipital encephalocoele and polydactyly