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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reflux nephropathy is known to be a major cause of renal failure in children. Vesico-ureteral reflux is usually diagnosed by voiding cysto-urethrography (VCG). However, it has been observed that conventional VCG is not always reliable for the diagnosis of ureteral reflux. In the case of a 5 year old girl with recurrent febrile urinary tract infection, VCG showed no ureteral reflux. Urodynamic study revealed a large bladder capacity and significant residual urine. Renal scintigram delineated a right renal scar. Simple ultrasound examination with videotape recording during voiding definitely demonstrated the presence of significant ureteral reflux when she voided, that is, there was marked dilatation of the right distal ureter and ballooning of the right renal pelvis on voiding, and quick refilling of the bladder concomitantly with the disappearance of the pelvic ballooning. Therefore, an ultrasound during voiding may be useful for diagnosing ureteral reflux in patients where a VCG does not reveal reflux.
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PMID:A case of ureteral reflux identified by ultrasound. 884 May 49

Vesicoureteral reflux (VUR) may be congenital or acquired. The most frequent form of congenital VUR is primary VUR. Its prevalence in adults is not exactly known, but it is higher in women, whose greater propensity for urinary tract infections increases the likelihood of an instrumental examination leading to the diagnosis of less severe cases. In men, even severe VUR may go undiagnosed for a long time. Primary VUR is due to a defect in the valve mechanism of the ureterovesical junction. In physiological conditions, the terminal ureter enters the bladder wall obliquely and bladder contraction leads to compression of this intravesical portion. Abnormal length of the intravesical portion of the ureter due to a genetic mutation (whose location is yet to be established) leads to VUR. In its less severe forms VUR may be asymptomatic, but in 50-70% of cases it manifests with recurrent cystitis or pyelonephritis. The manifestations leading to a diagnosis of VUR in adults, besides urinary tract infections, are proteinuria, renal failure and hypertension. The gold-standard diagnostic examination is a micturating cystourethrogram. Reflux nephropathy develops as a result of a pathogenetic mechanism unrelated to high cavity pressure or urinary tract infections but due to reduced formation of the normal renal parenchyma (hypoplasia or dysplasia). Abnormal renal parenchyma development is attributable to the same genes that control the development of the ureters and ureterovesical junction. VUR is considered only a marker of this abnormal development, playing no role in scar formation. There is no conclusive evidence regarding the indications for VUR correction. However, the risk that VUR leads to recurrent pyelonephritis and reflux nephropathy must be kept in mind. VUR certainly has to be corrected in women who contemplate pregnancy.
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PMID:[Vesicoureteral reflux in adults]. 2216 11

Reflux nephropathy and vesicoureteral reflux are two of the most important abnormalities in the upper urinary system in which toxins and bacteria from the bladder infect the ureter and the kidney and initiate renal scar formation. A quantitative analysis that characterizes urine flow will further help our understanding of the ureter and also assist in the design of flow aided devices such as valves and stents to correct reflux situations. Here, A numerical simulation with fluid-structure interactions (FSI) using arbitrary Lagrangian-Eulerian (ALE) formulation and adaptive mesh procedure was introduced and solved to perform ureteral flow analysis. Incompressible Navier-Stokes equations were utilized as the governing equations of fluid domain. Ureteral in-vivo morphometric data during peristalsis were used to construct the presented model. A nonlinear material model was used to exhibit ureteral wall mechanical properties. Direct coupling method was used to solve the solid, fluid and interface equations simultaneously. Results showed that recirculation regions formed against the jet flow, neighboring the bolus peak. Through wave propagation, separation occurred behind the moving bolus on the wall and ureteropelvic reflux began from that location and extended upstream to the ureteral inlet. The maximum luminal pressure consistently occurred behind the urine bolus during peristalsis. The measured magnitude of maximum volumetric flow rate resulted from isolated bolus transportation was 0.92 ml/min. In conclusion; due to presence of fluid inertial forces during peristalsis, the function of ureteropelvic junction in prevention of reflux is significant, especially at the beginning of peristaltic wave propagation. Moreover, modeling of ureteral function using imaging data will be valuable and it may help physicians to diagnose and cure the abnormalities.
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PMID:A biomechanical simulation of ureteral flow during peristalsis using intraluminal morphometric data. 2221 50