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.
On this page:
Pathology
Ureteric obstruction during active nephrogenesis results in cystic renal dysplasia; the earlier and longer the obstruction the more severe the histopathological changes of dysplasia 2.
Causes
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
Associations
Associated anomalies may be present in up to 50% of cases can include:
- VACTERL association 4
- congenital heart disease 4
- CNS abnormalities 4
- congenital gastrointestinal malformations 4
Radiographic features
Ultrasound
The kidneys are usually normal to small 1,3 in size with highly echogenic cortices, loss of cortico-medullary differentiation, and scattered cysts (usually smaller than those seen with multicystic dysplastic kidneys) 1. The reniform shape is often preserved until late in the disease.
Differential diagnosis
General differential considerations include:
- multicystic dysplastic kidneys: no distal obstruction
- Meckel-Gruber syndrome: has occipital encephalocoele and polydactyly