Autosomal Recessive Polycystic Kidney
Autosomal recessive polycystic kidney (PCK; Potter type I) is an autosomal recessive disorder, previously termed infantile PCK, characterized by bilateral microcystic change of renal tubules leading to enlarged non-functional kidneys with maintenance of their reniform shape. Most cases manifest in utero but some may be evident after birth or childhood. PCK may be associated with abnormality of fibrocystin, a receptor protein that acts in collecting-duct and biliary differentiation.
Fig 1
Incidence: 1 in 40,000-50,000 births, male/female, 1:1.
Sonographic findings:
- Bilateral enlarged (above the 90th percentile for length and width), echogenic kidneys with reniform shape. Fig 2, Fig 3, Fig 4, Fig 5
- Oligohydramnios with non-visualization of the bladder, usually not before 15 weeks.
- Pulmonary hypoplasia.
- Usually diagnosed after 18 weeks.
Fig 1: Schematic drawing of polycystic kidney (enlarged reniform shape)
Fig 2: Polycystic kidneys Coronal scan of the abdomen: symmetrical markedly enlarged echogenic kidneys (* = renal pelvis)
Fig 3: Polycystic kidneys Cross-sectional scan of the abdomen: symmetrical markedly enlarged echogenic kidneys (* = renal pelvis, arrowhead = spine)
Fig 4: Polycystic kidneys Coronal scan of the abdomen: symmetrical markedly enlarged echogenic kidneys
Fig 5: Polycystic kidneys Oblique coronal scan of the abdomen: symmetrical enlarged echogenic kidneys containing numerous microcystic lesions (* = renal pelvis)
Video clips of multicystic dysplastic kidney (MCDK)
Polycystic kidney: Bilateral enlarged echogenic kidneys with pyelectasis
Polycystic kidney: Bilateral enlarged echogenic kidneys with severe oligohydramnios
Associations: Hepatic fibrosis, Meckel Gruber syndrome, trisomy 13.
Management: Termination of pregnancy can be offered. Vaginal delivery without electronic fetal monitoring in labor is appropriate.
Prognosis: Very poor, particularly the cases with severe oligohydramnios and fetal kidneys >4 SD.
Recurrence risk: About 25%.