Micturition cystourethrogram
A voiding cystourethrogram , abbreviated MZU or MCU , English. voiding cystourethrography (VCUG), is a medical examination procedure for the detection of a backflow of urine via the ureters (ureter) into the renal pelvis ( vesico-uretero-renal reflux, VUR ), as well as for the assessment of anatomical or functional disorders of the urinary bladder emptying and in particular for the assessment of the posterior urethra. A catheter is placed through the urethra into the urinary bladder and through this the urinary bladder is filled with an X-ray contrast medium. Since catheterization in infants is difficult because the urethra is still very small, the contrast medium can also be injected into the urinary bladder with a syringe through the abdominal wall. After placing the patient under fluoroscopy , contrast-filled bladder bilddokumentiert and inspected targeted initially. A descent of the bladder, bladder diverticulum, fistulas or an irregularly configured bladder shadow can be displayed. Then, when urinating, it is examined whether the contrast medium flows back to the respective kidney via one of the two ureters, contrary to the intended route . The cause of the retrograde contrast medium flow can be a primary refluxive ureter, a subvesical obstruction or a functional obstruction in the case of dyssynergic sphincter.
It is important to the final receptacle of the bladder, with the one for a contrast media extravasation is evident, on the other hand can residual urine or Pseudorestharn also - by antegrade overrun of contrast agent from the refluxing ureter - are documented. In the case of a neurogenic reflex bladder, there is no central control, the detrusor contractions are no longer coordinated with the contractions of the external sphincter urethral muscle ( detrusor-sphincter dyssynergy ). Here, the MZU typically shows the image of a so-called Christmas tree bubble with pseudodiverticula, trabeculae and reflux. In this situation, during micturition, an onion-shaped dilation of the proximal urethra can occur. Overall, there is a high-pressure system that can be detected by the MZU (in combination with urodynamics ), which can lead to permanent damage to the kidneys due to reflux.
indication
Invasive primary diagnostics for the detection of reflux-associated urinary transport disorders in renal pelvic ectasia, deterioration of kidney function (here primarily in children), recurrent pyelonephritis in children and adults. Urethal diverticulum of the woman. In pediatric urology diagnosis of congenital anomalies, such as ureterocele, bladder exstrophy , ectopic Harnleiterostien prune belly syndrome , for further diagnostic evaluation already intrauterine seen Harntransportstörungen with consecutive renal pelvis and ureter ectasia , the result of congenital subvesical obstructions are, for example, the urethra flap . Recurrent urinary tract infections in girls, one-time urinary tract infections in boys.
Risks
Since the procedure is an X-ray examination, it always means a certain amount of radiation . However, the dose is in such a low range that what is known as a stochastic risk must be expected. Since a foreign body is pushed through the urethra and the bladder is also filled with liquid from the outside, there is also the risk that the examination will trigger a urinary tract infection. It is therefore customary, at least in pediatrics, to carry out preventive antibiotic treatment for three days.
Children can find the procedure very uncomfortable and develop symptoms such as paruresis ; it is recommended to use preventive sedation.
Alternative investigation method
see main article micturition urosonography
If the VUR and the consecutive renal pelvic celiac dilation are to be demonstrated sonographically, an ultrasound contrast medium must be used. This diagnostic method does not represent any radiation exposure for the patient, is sensitive, but expensive and time-consuming. Therefore it is only carried out in routine care at a few (mostly pediatric radiology ) centers.
literature
- S1 guideline urinary tract infection - diagnostic imaging of the Society for Pediatric Radiology (GPR). In: AWMF online (as of 2013)
Individual evidence
- ^ HU Schmelz, H Leyh: Specialist examination in urology. 1000 commented exam questions . Thieme-Verlag, 2004.
- ↑ Anoush Azarfar, Mohammad Esmaeeili, Azadeh Farrokh, Ali Alamdaran, Aghilallah Keykhosravi: Oral Midazolam for Voiding Dysfunction in Children Undergoing Voiding Cystourethrography: A Controlled Randomized Clinical Trial . In: Nephro-urology Monthly . tape 6 , no. 3 , May 1, 2014, ISSN 2251-7006 , doi : 10.5812 / numonthly.17168 , PMID 25032141 , PMC 4090665 (free full text).
