Norm of Antegrade Pyelography
The selected ureter fills from the renal pelvis to the urinary bladder. Normal renal pelvic, ureteral, and urinary bladder contours are demonstrated radiographically after the injection of radiopaque contrast material.
Usage of Antegrade Pyelography
Most commonly requested in clinical scenarios where ureteral obstruction is suspected but cannot be diagnosed effectively by intravenous pyelography (IVP) or cystoscopy and retrograde pyelography. Used for detection of synchronous tumor of the upper urinary tract, ureteropelvic laceration after blunt body trauma, or ileal conduit stenosis. Frequently performed with the placement of percutaneous nephrostomy tubes in the treatment of urinary tract obstruction and analysis of ureteral stent placement.
Description of Antegrade Pyelography
Antegrade pyelography is an invasive radiographic procedure in which radiocontrast material is injected percutaneously into the renal pelvis. The flow of the contrast material is then observed as it progresses into the ureter and urinary bladder. Hydronephrosis or obstruction of the flow of the radiocontrast material into the urinary bladder is diagnostic of urinary tract obstruction and may be suggestive of the need to place a percutaneous nephrostomy tube.
Professional Considerations of Antegrade Pyelography
Consent form IS required.
Allergic reaction to the radiocontrast material or anesthetic agents, bleeding (bladder clots, hematuria, perinephric hematoma), bowel perforation, infection, laceration of the renal collecting system with resulting urine leaks, pneumothorax.
Allergy to radiocontrast material, hemorrhagic diathesis.
During pregnancy, risks of cumulative radiation exposure to the fetus from this and other previous or future imaging studies must be weighed against the benefits of the procedure. Although formal limits for client exposure are relative to this risk-benefit comparison, the United States Nuclear Regulatory Commission requires that the cumulative dose equivalent to an embryo/ fetus from occupational exposure not exceed 0.5 rem (5 mSv). Radiation dose to the fetus is proportional to the distance of the anatomy studied from the abdomen and decreases as pregnancy progresses. For pregnant clients, consult the radiologist/radiology department to obtain estimated fetal radiation exposure from this procedure.
- This test is generally performed by a urologist or an interventional radiologist in an area equipped with fluoroscopy or ultrasound equipment.
- A formal assessment to rule out hemorrhagic diathesis (PT, PTT, bleeding time, platelet count) as well as baseline determination of hematocrit and hemoglobin is advisable. A baseline urinalysis is also often obtained. It is useful to determine if the client will permit transfusion in the event of hemorrhage. If not, it may be necessary to reconsider the procedure.
- Orders may include a 4-hour fast from food and a sedative.
- Vital signs (blood pressure reading, pulse rate, respiratory rate) immediately before the procedure are indicated.
- Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
- In the fluoroscopy or sonography suite, the position of the renal pelvis is demonstrated radiographically. A posterior vertical approach to the kidney is usually selected.
- The flank over the renal pelvis is prepped with an iodine solution, and sterile drapes are applied to create a sterile field.
- A 22-gauge needle is advanced into the renal pelvis under fluoroscopic or ultrasonographic guidance. Once within the collecting system, urine samples can be obtained and radiocontrast material injected to confirm the location of the needle tip within the renal pelvis.
- At this point, a guidewire is advanced through the needle, allowing placement of larger introducer needles or urostomy catheters, or both types. Further radiocontrast material can be injected to complete the antegrade pyelogram procedure.
- Frequent determination of the vital signs is indicated in the immediate postprocedure period. Vital signs are generally obtained at 15-minute intervals for the first hour after the procedure and then at frequent intervals as specified by the physician performing the test.
- Close monitoring of the urine output and observation for the development of hematuria are important. The client may have a nephrostomy bag as well as a Foley catheter bag after the pyelography, so separate records of each output source may be necessary.
- Serial determinations of hematocrit, hemoglobin, creatinine, and serum electrolytes may be indicated.
- If nephrostomy tubes have been placed, dressing checks and changes may be needed.
- New fluid and antibiotic orders may need to be executed after the pyelography procedure.
Client and Family Teaching
- The need to frequently monitor vital signs and urine output should be discussed.
- Gross hematuria is not unusual after this procedure, and a relatively small amount of blood will produce red urine. The client should be reassured that this development generally is to be expected and does not necessarily indicate an unfavorable outcome.
- Special positioning of the client may be required because of the nephrostomy tubes, and this should be explained to the client.
Factors That Affect Results
- Postprocedure bleeding or infection.
- Hematuria resulting in clotting of nephrostomy tubes.
- Formation of bladder clots causing pain and diminished urine output.
- Accelerated urine output after nephrostomy tube placement (post obstructive diuresis), resulting in volume depletion (hypotension, tachycardia, electrolyte abnormalities).
- Intravenous pyelography, CT scan, and nuclear magnetic resonance scanning are noninvasive alternative diagnostic modalities useful in the evaluation of urinary tract obstruction.
- Renal insufficiency is a relative contraindication for the administration of intravenous radiocontrast material but is not a contraindication for antegrade or retrograde pyelography.
- See also Retrograde pyelography.