Infants with normal urination may also have a separated renal pelvis.
Separation of the renal pelvis in infants may be caused by normal holding of urine, or it may be caused by ureteral malformation, renal hypoplasia, urethral stenosis or obstruction.
1. Normal urine holding: If the infant drinks a lot of water in a short period of time and does not urinate in time, the renal pelvis may separate.
2. Ureteral malformation: The infant’s ureter has malformation such as ureteral atresia, which prevents urine from draining out, thus accumulating at the junction of the renal pelvis and ureter, leading to separation of the renal pelvis.
3. Inadequate kidney development: infants with kidney diseases such as hydronephrosis and underdevelopment of the kidneys during the fetal period may also have separated renal pelvis.
4. Urethral stenosis or obstruction: infants with congenital urethral stenosis or obstruction can cause urine to remain in the urinary system, resulting in separation of the renal pelvis in infants.
Once an infant develops pyelolithiasis, the cause should be identified promptly, and physiologic factors should be ruled out, and the infant should be seen promptly.