Table 1.
Categories of CAKUT disorders
| Type of Anomaly | CAKUT Disorder | Definition |
|---|---|---|
| Kidney number | Renal agenesis | Unilateral or bilateral, kidney and outflow system fail to form |
| Kidney size and morphology | Renal hypoplasia | Unilateral or bilateral, kidney shape is normal, but smaller in size and reduced number of nephrons |
| Renal dysplasia | Unilateral or bilateral, kidney shape and tissue differentiation is abnormal, reduced number of nephrons | |
| Multicystic dysplastic kidney | Multiple cysts within a dysplastic kidney giving it an abnormal shape | |
| Kidney position | Horseshoe kidney | Kidneys are fused posteriorly forming a horseshoe shape |
| Ectopic/pelvic kidney | Kidney in an abnormal location, typically pelvic | |
| Outflow abnormalities | Ureteropelvic junction obstruction | Unilateral or bilateral, junction between kidney and ureter is obstructed, preventing drainage of urine from pelvis of the kidney |
| Vesicoureteric reflux | Unilateral or bilateral, junction between ureter and bladder is defective, resulting in urine backflow from bladder | |
| Duplex collecting system | Unilateral or bilateral, duplication of ureter and kidney pelvis, can be accompanied with duplicated kidneys; outflow system may reflux or exhibit obstruction | |
| Megaureter | Unilateral or bilateral, distension of ureter resulting in defects in impaired urine flow | |
| Posterior urethral valves | Membrane that forms in urethra preventing emptying of bladder, limited to males |
Definitions have been adapted from Potter’s Normal and Abnormal Development of the Kidney (58). CAKUT, congenital anomalies of the kidneys and urinary tracts.