Pediatric Obstructive Uropathy

Abstract

Congenital obstructive uropathy, a major cause of chronic kidney disease, is defined as kidney, ureter, and/or bladder injury associated with obstruction of the urinary tract. Congenital obstructive uropathy arises from malformation of the renal collecting system, constituted by the calices, pelvis, and ureter, the bladder and urethra, and the connections between the ureter and pelvis and the ureter and bladder. Congenital obstructive uropathy is caused by a polymorphic group of unilateral or bilateral upper and lower urinary tract malformations. Presenting most commonly as antenatal hydronephrosis, these disorders range in severity from self-resolving pelviectasis and/or hydroureter to a fixed physical obstruction of the ureteropelvic junction, ureterovesical junction, or urethra causing kidney injury. In this chapter, the clinical assessment of urinary tract obstruction and the pathobiology of obstructive uropathy-associated kidney injury are described from observations in animal models and descriptive analyses of human kidney tissue. Genes and genetic pathways that control the embryonic development of the ureter and its connections with the bladder are highlighted as well genetic mutations associated with malformation of the ureter, ureteropelvic junction, ureterovesical junction, and urethra. A clinical classification of antenatal urinary tract dilatation is presented; for each specific disorder, genetic etiologies, diagnosis, use of static and dynamic imaging modalities, natural history, and treatment approaches are described.