It occurs in approximately 1 in every 1500 live births, is most commonly seen in males, involves the left ureter twice as often as the right ureter. UPJ obstruction is transient in most cases. Lower urinary tract obstruction
Lower urinary tract obstruction involves the lower ureters, urinary bladder and the urethra. Ureterovesicular junction obstruction
Ureterovesicular junction obstruction (UVJ obstruction) is an obstruction at the level of the ureter and bladder. It accounts for 20% of cases of hydronephrosis detected in utero. It is also most commonly seen in males and involved both sides of the urinary tract in approximately 25% of cases. Posterior urethral valves
Posterior urethral valves (PUV) is an obstruction at the level of the urethra. It occurs in approximately 1 in every 5000 to 8000 live births and only occurs in males. Since PUV always affects both sides of the urinary tract, patients with posterior urethral valves are at the greatest risk for developing chronic kidney disease and end-stage renal disease due to obstructive uropathy. Ureterocele
A ureterocele is a cystic dilation of the end of the ureter that can occur in the bladder and/or in the urethra. It occurs in approximately 1 in every 5000 live births, is most commonly seen in females and involves both ides of the urinary tract in approximately half of cases. Urethral stenosis
Urethral stenosis is a narrowing of the urethra that prevents urine from exiting the bladder. Diagnosis
Prenatal diagnosis
Bladder outlet obstruction can be identified during routine prenatal ultrasonography as dilation of the fetal urinary tract and decreased amniotic fluid levels.
Simple hypoplasia
Kidneys that are small for age but still have normal renal architecture. This leads to a decrease in the number of nephrons, or functional units of the kidney. Dysplasia
Malformation of kidney or bladder architecture. A dysplastic kidney is typically small for age and may contain cysts. A multicystic dysplastic kidney is an extreme example of renal dysplasia. Isolated collecting duct dilation
Dilation of the renal pelvis, ureters, or both. Also called hydronephrosis. Anomalies of position
Kidneys and ureters located in incorrect position, including horseshoe kidney and ectopic ureters. See also
Overflow incontinence

References


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