How to read retrograde urethrogram contraindications

Retrograde ureteropyelography: Contrast X-ray of the ureter

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Abbreviation: RUP (retrograde ureteropyelography), RPG (retrograde pyelography).



Indications for retrograde pyelography

Retrograde pyelography is rarely performed as the primary diagnostic measure; it is an alternative to the excretory urogram or abdominal CT scan in the case of contraindications for contrast media containing iodine. The retrograde application of iodine-containing contrast agent is also possible in the case of contrast agent allergy (Blackwell et al., 2017) (Weese et al., 1993). In principle, it is indicated for nephrolithiasis, macrohematuria, urinary obstruction, injuries and tumors of the upper urinary tract. The most common application is as an oriented imaging measure before ureterorenoscopy or as part of a ureteral splint insert or replacement. .


Retrograde pyelography technique

After cystoscopy, a ureteral catheter (5–6 Ch) is inserted into the corresponding ostium and an empty image of the abdomen (if necessary only half-way) is made. Then contrast agent is slowly injected into the ureter under fluoroscopy [Fig. retrograde pyelography with video cystoscopy and digital X-ray]. If the contrast medium does not reach the upper hollow system in sufficient concentration, the ureteral catheter is pushed proximally into the renal pelvis and contrast medium is carefully and slowly applied there under fluoroscopy. The examination is evaluated in real time with the help of fluoroscopy, significant still images are saved for documentation.




Normal findings on retrograde pyelography

Refer to the Abdomen X-ray section for normal results from the blank image. After a contrast medium injection, a narrow ureter is contrasted, the renal pelvic calyx system is shown without urinary congestion [Fig. normal x-ray anatomy of the renal calyx and radiological signs of urinary obstruction]. There are no contrast medium recesses in the course of the urinary tract. After removing the ureteral catheter, the contrast medium drains into the urinary bladder.





Complications

Injury to the ureter

Tight or kinked ureters, tumors or ureteral stones can prevent the ureteral catheter from advancing; lack of caution leads to ureter perforation and advancement of the catheter into the ureteral wall or the retroperitoneum. If there is resistance, further advancement can be attempted with the aid of a hydrophilic coated working wire and under fluoroscopy.

Fornix rupture

Injecting with too much pressure can lead to pyelolymphatic reflux [Fig. pyelolymphatic reflux] or extravasation of the contrast medium in the area of ​​the fornices [Fig. Fornix rupture]. The aspiration of urine from the renal pelvis before the application of the contrast medium and the slow injection reduce the likelihood of this.

Urosepsis

Retrograde pyelography can cause fulminant urosepsis in patients with infected urinary stasis kidneys. The aspiration of urine from the renal pelvis before the application of the contrast medium enables a urine culture and lowers the risk of bacterial infiltration. Contrast media should be applied as sparingly as possible; an orienting representation of the renal pelvis is sufficient for the correct positioning of a ureteral splint. Clarification of the cause of the obstruction must be postponed to a later date.

Incompatibility of the contrast medium

The retrograde application of iodine-containing contrast agent is also possible in the case of renal insufficiency, iodine intolerance and contrast agent allergy. Contrast medium intolerance has rarely been published, risk factors are injection under pressure with extravasation. As with performing an excretory urography, an emergency kit for the treatment of anaphylaxis should be available (Blackwell et al., 2017) (Weese et al., 1993).







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literature

Blackwell, R. H .; Kirshenbaum, E. J .; Zapf, M. A. C .; Kothari, A. N .; Kuo, P. C .; Flanigan, R. C. & Gupta, G. N.
Incidence of Adverse Contrast Reaction Following Nonintravenous Urinary Tract Imaging.
European urology focus, 2017, 3, 89-93.