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 2.
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 4
- congenital heart disease 4
- CNS abnormalities 4
- congenital gastrointestinal malformations 4
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.
General differential considerations include:
- multicystic dysplastic kidneys: no distal obstruction
- Meckel-Gruber syndrome: has occipital encephalocoele and polydactyly
- 1. Mercado-deane MG, Beeson JE, John SD. US of renal insufficiency in neonates. Radiographics. 22 (6): 1429-38. doi:10.1148/rg.226025047 - Pubmed citation
- 2. Matsell DG, Mok A, Tarantal AF. Altered primate glomerular development due to in utero urinary tract obstruction. Kidney Int. 2002;61 (4): 1263-9. doi:10.1046/j.1523-1755.2002.00274.x - Pubmed citation
- 3. Peters CA, Carr MC, Lais A et-al. The response of the fetal kidney to obstruction. J. Urol. 1992;148 (2 Pt 2): 503-9. - Pubmed citation
- 4. Blane CE, Barr M, Dipietro MA et-al. Renal obstructive dysplasia: ultrasound diagnosis and therapeutic implications. Pediatr Radiol. 1991;21 (4): 274-7. - Pubmed citation
- 5. Fong KW, Rahmani MR, Rose TH et-al. Fetal renal cystic disease: sonographic-pathologic correlation. AJR Am J Roentgenol. 1986;146 (4): 767-73. AJR Am J Roentgenol (abstract) - Pubmed citation