Dilatation urinary tract

Eernbach SK (1992) The dilated urinary tract in children. Urol Radiol 14 34-42... 

If surgery is chosen, the morphology of the urinary tract must be assessed. Intravenous urography (IVU) used to be performed for this purpose. However, it is an irradiating technique that requires injection of contrast material. Also, the poorer the function, the poorer the opacification of the dilated urinary tract will be. Therefore, nowadays more and more authors advocate the use of MR urography for the assessment of a dilated urinary tract (Fig. 13.20) (Nolte et al. 1992 Borthne 1999). Furosemide is usually injected in order to increase the diuresis and to optimize the visualization of the urinary tract. T2... 

Fig. 15.18. Pyonephrosis, uro-lithiasis and obstructive uropathy. Ultrasound. Sagittal scan of the left kidney. A li-thiasis is visible within the dilated urinary tract (arrow). The urine appears echogenic...

Renal dysplasia (dilated urinary tract) Lymphangioma (intrarenal, mostly ) Acute lymphoblastic leukaemia... 

Renal ultrasound (uses sound waves to assess size, position, and abnormalities of the kidney dilatation of the urinary tract can be seen with postrenal ARF)... 

Changes to the urinary tract in pregnant women predispose them to an increased incidence of bacteriuria, and subsequent urinary tract infections that may follow. These changes are not limited to amino acid and other nutrient concentrations in the urine, but extend to physiologic changes such as reduced bladder tone and dilation of the renal pelvis and ureters.22,23... 

Noradrenaline is released at target organs and leads to the contraction of cardiac muscle and an increase in heart rate. It relaxes smooth muscle and reduces the contractions of the GIT and urinary tracts. It also reduces salivation and reduces dilation of the peripheral blood vessels. 

Furosemide (Lasix) will enhance the detection of a dilated collecting system by rapid washout of the radiotracer from the pelvis and ureter, while in the case of urinary tract obstruction, no change of pelvic retention and in the shape of the time-activity curve is seen (O Reilly 1992). 

Noradrenaline is released particularly at the target organs and ultimately gives rise to the ensuing contraction of the cardiac muscles and ultimately an enhancement in the heart rate. Besides, it is also helpful in relaxing the smooth muscles and thereby causes a visible reduction in the contractions of the Gl-tract as well as the urinary tract. It also minimises a distinct reduction in salivation and lowers dilatation of the peripheral blood vessels particularly. 

Inflammation of the urinary tract may nuniic appendicitis. A stone in the right ureter may be a cause of right lower abdominal pain. In acute renal colic, the collecting system may not be dilated. Doppler sonography can be used to diagnose the acute obstruction. Furthermore, a carefid search for perirenal fluid at the poles of the kidney should be performed. 

The dilatation of the urinary tract is prerequisite for generating virtual endoscopy of static-fluid MRU data sets, since the dilatation of the ureter or renal pelvis increases the availability of bright image pixels and, consequently, the voxels that VE can use to reconstruct the lumen in three dimensions and to create the virtual space for endoscopic navigation. The feasibility of virtual endoscopy with MRU has been proposed both with and without gadolinium (Nolte-Ernsting et al. 1999 Neri et al. 2000). 

A basic study of the urinary tract should start with an explanation to the parents, and to the child if he or she is old enough to understand. The bladder is studied first, especially in infants, since reflex micturition is frequent when the transducer is placed on the abdominal wall (avoid unheated jelly). Examination of the full bladder includes analysis of urine echogenicity and the bladder wall. It is extremely important to look for dilated ureters(s) behind the... 

Riccabona M (2004) Pediatric MRU-Its potential and its role in the diagnostic work-up of upper urinary tract dilatation in infants and children. World J Urol 22 79-87... 

Indications for DIG (Mandell et al. 1997a,b) include female infants (<1 year of age) with a urinary tract infection (UTI) and a normal ultrasound or with a prenatal ultrasound diagnosis of hydronephrosis who postnatally are either normal or who have mild dilatation, and boys (<3 years of age) who require follow-up cystography. 

The bladder neck is the poorly delineated junction between the bladder and urethra at the level of the internal urethral sphincter. At the beginning of voiding the bladder floor descends and becomes funnel-shaped and in continuity with the proximal urethra. At the end of voiding, the bladder base ascends to its normal position. A wide bladder neck and a dilated proximal urethra during voiding (wide bladder neck anomaly and spinning top urethra, respectively) are variants that will be discussed in Chapter 14 on nonneurogenic bladder-sphincter dysfunction (functional disorders of the lower urinary tract). 

In all children with a horseshoe kidney, VUR should be excluded. The upper urinary tract dilatation may be secondary to VUR (Fig. 4.2d). More than 100 renal malignancies have been reported in patients with horseshoe kidney (Buntley 1976). The risk of developing a Wilms tumor increases sevenfold in patients with a horseshoe kidney (Mesrobi an etal. 1985). 

Congenital anomalies may involve any level of the collecting system the most usual presentation is urinary tract dilatation that may already be detected during fetal life. The role of imaging is to determine the origin of the dilatation, i.e., obstructive versus non-obstructive (Table 5.1 lists the causes of urinary tract dilatation). Other useful information includes the level of the obstruction and its impact on renal function. All these data are important in order to determine the best therapeutic approach. 

In pediatric uronephrology, US has maintained a central position whatever the anomaly, it will be performed first and will determine the subsequent work up. US is very efficient for the demonstration of dilatation of the urinary tract and the level of obstruction yet, the method cannot differentiate... 

US is the central imaging technique for the visualization of a dilated collecting system. Morphology of the urinary tract is best assessed by MR imaging or CT (IVU is more and more abandoned). Function is best assessed by isotope studies. 

The first step towards the detection of obstruction is US (Fig. 5.9), the main landmark being the demonstration of dilatation of the urinary tract. Dilatation is best evaluated on an anteroposterior measurement of the renal pelvis on a transverse scan of the kidney. In the newborn, a pelvic diameter greater than 7 mm is considered abnormal in older children, a diameter higher than 10 mm should be considered abnormal. The following step in the work-up of a uropathy is VCU. Once VUR is excluded, it becomes more probable that the urinary tract dilatation is secondary to obstruction. It is noteworthy that VUR and obstruction may coexist in the same collecting... 

Fig. 5.9a,b. US of urinary tract dilatation (UPJ obstruction), a Transverse and b sagittal scan of the left kidney... 

Consequently, other imaging methods have been used or have been developed. For many years, IVU has been used for the diagnosis of urinary tract obstruction. Signs of obstruction include the demonstration of dilatation and delayed filling of the collecting system (Fig. 5.12a). On imaging, especially on IVU, the dilatation of the renal pelvis and calyces... 

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