In antegrade pyelography, a contrast dye is injected directly into one of the kidneys, and a series of x-ray films is taken to visualize the flow of dye through the ureter, which connects the kidney to the bladder. Because the dye is more dense than urine, it will settle in the ureter on top of any obstruction, thereby revealing its location.
Antegrade pyelography is performed when intravenous and retrograde pyelography cannot be done or fail to provide an adequate picture of the ureter.
Purpose of the Antegrade Pyelography
- To determine the site of a known or suspected ureteral obstruction caused by a stricture, stone, or tumor
- To aid in the placement of a nephrostomy tube, a catheter that is surgically positioned in the kidney for drainage
- To assess the function of the upper collecting system of the kidney after surgery
Who Performs Antegrade Pyelography
- A physician
Special Concerns about Antegrade Pyelography
- People who have an allergy to shellfish or iodine may experience an allergic reaction to the contrast dye.
- Pregnant women should not undergo this test because exposure to ionizing radiation may harm the fetus.
- This test may not be safe for people with bleeding disorders.
Before the Antegrade Pyelography
- As your physician explains what will happen, ask any questions you may have.
- You will be given a consent form to sign.
- Tell your doctor if you are or think you may be pregnant.
- If you are allergic or have sensitivities to latex, adhesives, anesthesia or any other medications, be sure to alert your doctor.
- Tell your doctor if you regularly take anticoagulant drugs. You may be instructed to discontinue them for some time before the test.
- Be sure to tell your doctor if you have a known shellfish or iodine allergy or have ever had an adverse reaction to x-ray contrast dyes.
- Do not eat solid food for 8 hours before the test; you may drink clear fluids until 3 hours before the test.
- Be sure to remove any clothing, jewelry or other objects that may interfere with the procedure.
- You will be asked to disrobe and put on a hospital gown.
What You Experience
- You are asked to lie on your stomach on an examination table.
- The doctor locates the position of the renal pelvis (the area at the center of the kidney where urine collects) by means of ultrasound, fluoroscopy, or CT scanning.
- The skin over this site is marked and cleansed with an antiseptic solution. A local anesthetic is then injected into the area; this injection may cause brief discomfort.
- You will be asked to hold your breath as the doctor, using fluoroscopy or ultrasound as a guide, inserts a hollow needle into your kidney.
- If necessary, a syringe may be used to drain urine through the needle. (Urine samples may be sent to a laboratory for analysis.)
- A contrast dye is injected through the needle into the kidney. You may feel a brief burning or flushing sensation as the dye is injected.
- X-ray films are obtained to visualize the kidney and ureter. Remain still as each x-ray is taken.
- A catheter (nephrostomy tube) may be left in place for further drainage of urine, if necessary.
- The test takes about 60 to 90 minutes.
Risks and Complications of Antegrade Pyelography
- X-ray exams involve minimal exposure to radiation.
- Possible complications include bleeding at the site of needle insertion.
- Some people may experience an allergic reaction to the iodine-based contrast dye, which can cause symptoms such as nausea, sneezing, vomiting, hives, and occasionally a life-threatening response called anaphylactic shock. Emergency medications and equipment are kept readily available.
After the Antegrade Pyelography
- A pressure dressing is applied to the site of needle insertion.
- You will rest in a recovery room for 15 to 30 minutes. Your vital signs will be monitored, and pain medication will be provided if necessary.
- If no complications develop, you are usually free to leave the testing facility.
- You will be instructed to keep track of your urine output and report any urinary retention. Your urine may contain blood at first, causing a slight pink tinge; this should resolve after voiding a few times. If blood persists or you see bright red blood or blood clots, notify your physician.
- Delayed allergic reactions to the contrast dye, such as hives, rash, or itching, may appear 2 to 6 hours after the procedure. If this occurs, your doctor will prescribe antihistamines or steroids to ease your discomfort.
- You may be given prophylactic antibiotic drugs for several days to prevent infection.
- You may resume your normal diet and any medications withheld before the test.
- Report to the doctor any signs of infection, such as chills, fever, rapid breathing, or a feeling of faintness.
Antegrade Pyelography Results
- Your doctor will examine the x-rays and other test data to locate any obstruction or blockage of urine flow or other abnormalities.
- If a definitive diagnosis can be made, appropriate treatment will be initiated, depending on the specific problem.
- In some cases, additional tests, such as a CT scan, a nuclear scan, or ureteroscopy, may be needed to establish a diagnosis and determine the extent of the problem.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media