What is an antegrade pyelogram?
An antegrade pyelogram is a type of x-ray used to diagnose an obstruction of the upper urinary tract. During the procedure, a contrast dye is injected into a portion of the ureter (narrow tube that carries urine from the kidney to the bladder) closest to the kidneys called the renal pelvis. The flow of the contrast dye can then be observed with x-ray images as it moves from the kidneys into the ureters and urinary bladder.
Fluoroscopy (a type of x-ray "movie") or ultrasound (high frequency sound waves) may be used during the procedure to locate the kidneys and ureters.
What is an x-ray?
X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film. X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body structures onto specially-treated plates (similar to camera film) and a "negative" type picture is made (the more solid a structure is, the whiter it appears on the film).
Other related procedures that may be used to diagnose problems of the upper urinary tract include kidney, ureters, and bladder (KUB) x-ray, computed tomography (CT scan) of the kidneys, renal ultrasound, renal angiogram, intravenous pyelogram (IVP), retrograde pyelogram, and renal venogram . Please see these procedures for additional information.
How does the urinary system work?
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The body takes nutrients from food and converts them to energy. After the body has taken the food that it needs, waste products are left behind in the bowel and in the blood.
The urinary system keeps chemicals, such as potassium and sodium, and water in balance, and removes a type of waste, called urea, from the blood. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys.
Other important functions of the kidneys include blood pressure regulation, and the production of erythropoietin, which controls red blood cell production in the bone marrow.
Urinary system parts and their functions:
- two kidneys - a pair of purplish-brown organs located below the ribs toward the middle of the back. Their function is to:
- remove liquid waste from the blood in the form of urine
- keep a stable balance of salts and other substances in the blood
- produce erythropoietin, a hormone that aids the formation of red blood cells
- regulate blood pressure
The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney.
- two ureters - narrow tubes that carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.
- bladder - a triangle-shaped, hollow organ located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to two cups of urine for two to five hours.
- two sphincter muscles - circular muscles that help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder
- nerves in the bladder - alert a person when it is time to urinate, or empty the bladder
- urethra - the tube that allows urine to pass outside the body
An antegrade pyelogram may be used to visualize the ureters when other procedures, such as intravenous pyelogram and retrograde pyelogram, have not provided enough definitive information.
The antegrade pyelogram may be used to detect an obstruction of the urinary tract due to a stricture (narrowing), a kidney stone, a blood clot, or a tumor. In the presence of an obstruction, the injected contrast dye is unable to move properly through the kidney and this is detected on x-ray images.
An antegrade pyelogram may also be used to assess the kidneys or ureters prior to or after surgical treatment. If a blockage is found, a nephrostomy tube may be inserted during the procedure to divert the flow of urine past the obstruction.
There may be other reasons for your physician to recommend an antegrade pyelogram.
You may want to ask your physician about the amount of radiation used during the procedure and the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure, such as previous scans and other types of x-rays, so that you can inform your physician. Risks associated with radiation exposure may be related to the cumulative number of x-ray examinations and/or treatments over a long period of time.
If you are pregnant or suspect that you may be pregnant, you should notify your physician. Radiation exposure during pregnancy may lead to birth defects.
If contrast dye is used, there is a risk for allergic reaction to the dye. Patients who are allergic to or sensitive to medications, contrast dye, or iodine should notify their physician.
Patients with kidney failure or other kidney problems should notify their physician. In some cases, the contrast dye can cause kidney failure, especially if the person is taking Glucophage (a diabetic medication).
Possible complications of antegrade pyelogram include, but are not limited to, the following:
- urinoma formation
- blood clots in the nephrostomy tube, if placed, or clots in the bladder
- fast heart rate, low blood pressure, and electrolyte imbalance due to rapid urine loss after nephrostomy tube placement (shock)
An antegrade pyelogram may be contraindicated for patients with blood clotting disorders.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
- Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
- You will be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if something is not clear.
- You will need to fast for a certain period of time prior to the procedure. Your physician will notify you how long to fast, whether for a few hours or overnight.
- If you are pregnant or suspect that you may be pregnant, you should notify your physician.
- Notify your physician if you have ever had a reaction to any contrast dye, or if you are allergic to iodine.
- Notify your physician if you are sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local and general).
- Notify your physician of all medications (prescribed and over-the-counter) and herbal supplements that you are taking.
- Notify your physician if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.
- You may receive a sedative prior to the procedure to help you relax. Because the sedative may make you drowsy, you will need to arrange for someone to drive you home.
- You may be given antibiotics before and after the procedure.
- Based upon your medical condition, your physician may request other specific preparation.
An antegrade pyelogram may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your physician's practices.
Generally, an antegrade pyelogram follows this process:
- You will be asked to remove any clothing, jewelry, or other objects that may interfere with the procedure.
- If you are asked to remove clothing, you will be given a gown to wear.
- An intravenous (IV) line may be inserted into your arm or hand.
- You will be asked to lie face down on the x-ray table. An area of skin on your lower back will be wiped with an iodine solution to sterilize the area, and sterile drapes will be placed around it.
- Local anesthetic will be injected. With the help of ultrasound or fluoroscopic guidance, a needle will be advanced into the renal pelvis and the contrast dye will be injected. You may feel mild discomfort during the injection of the local anesthetic, as well as a brief feeling of warmth from the contrast dye.
- A series of x-rays will be taken at timed intervals as the dye travels through the ureters.
- Once the needle has been inserted, a thin wire may be threaded through the needle to allow placement of catheters, a nephrostomy tube, or other devices.
- If a nephrostomy tube is not needed, the physician will remove the needle.
- A sterile bandage/dressing will be applied.
Your recovery process will vary depending upon the type of procedure performed and your physician’s practices. After the procedure, you will be taken to the recovery room for observation. Once your blood pressure, pulse, and breathing are stable and you are alert, you will be taken to your hospital room or discharged to your home.
Your urine output will be monitored closely for volume and signs of blood. It may be red from even a small amount of blood. This is considered normal and does not necessarily indicate a problem. You may be instructed to continue monitoring your urine output for a day or so once you are at home.
You may experience pain when you urinate. Take a pain reliever for soreness as recommended by your physician. Aspirin or certain other pain medications may increase the chance of bleeding. Be sure to take only recommended medications.
Notify your physician to report any of the following:
- fever and/or chills
- redness, swelling, or bleeding or other drainage from the insertion site
- increased pain around the insertion site
- increase in the amount of blood in your urine
- difficulty urinating
Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.