Intravenous Pyelogram Procedure

Intravenous pyelography refers to a series of X-rays taken of the kidneys, their collecting or drainage system (the ureters), and the bladder. The ureters are the small tubelike structures that connect the kidneys to the bladder.

• An intravenous pyelogram (IVP) may be performed to detect a problem of the kidneys, ureters, and bladder. Most often, the IVP is done to locate a suspected obstruction to the flow of urine through the collecting system. The most common cause of blockage is a kidney stone. The IVP test also gives information about the functioning of the kidneys.

• In an IVP test, dye is injected via a catheter inserted in a person's vein, usually on the hand or the forearm. X-rays are then taken to follow the track of the dye through the system.

The dyes (also called radio contrast media) are of 2 types: ionic and nonionic. Both types of dye contain iodine but differ in 2 key ways: the rate of adverse reactions and the cost.

Although the overall rate of adverse reactions is relatively low with both, there is a greater incidence of adverse reactions with the less expensive ionic dye than with the nonionic.

• Minor reactions, which are infrequent and do not last long, include flushing, nausea, vomiting, and itching.
• A small percentage of people experience a severe reaction to the dye, such as difficulty breathing, speaking, or swallowing; swelling of the lips and tongue; low blood pressure; or loss of consciousness. People who have had a severe reaction after receiving the dye once should not be exposed to it again.
• Pregnant women should not have an IVP because of the risk of radiation exposure to the unborn baby.
• People with known kidney disease or failure should not have an IVP because the dye can worsen kidney function.
• Elderly people and those with diabetes, high blood pressure, heart disease, or evidence of dehydration are at risk of developing kidney failure following administration of the dye.
  • To avoid this complication, the kidney function should be tested with a blood test for creatinine, and the results should be known before the IVP is performed.
  • Those with diabetes who are taking metformin (Glucophage) will have to discontinue this medication prior to and for 2 days after the IVP. They should inform their doctor of the test, and the doctor will coordinate their management during that time.

The intravenous pyelogram may be performed as an emergency procedure or on an outpatient basis. In most cases, the IVP becomes an emergency procedure because you might arrive at the emergency department with symptoms (usually pain in the back and abdomen) that suggest a blockage to the flow of urine through the ureter. In this case, there is usually no time to "prepare" the bowel before the test is done.

• The emergency department staff will draw blood and start an IV line. The IV will be used to give medication to alleviate pain, nausea, and vomiting and to administer fluids as well as the dye used in the test. Your urine will be tested for abnormalities. While waiting for the IVP to be done, you should be lying down and resting, without any pain or discomfort.
• In non-emergency cases, typically you would go to the doctor's office with a complaint that suggests a problem with the kidneys, ureters, or bladder. The doctor might believe that an IVP would help in making the diagnosis but may not require that it be done immediately. In that case, you will need to prepare for the test. Preparation will involve the use of laxatives and, in some cases, enemas to cleanse the bowel of stool. Additionally, you are usually asked not to eat for 8-12 hours before the test is done.

You will go to the X-ray department for the IVP test. While you are lying face up on the X-ray table, dye is injected through an IV placed in a vein.

• The X-rays are taken at several intervals, such as at 0, 5, 10, and 20 minutes. Zero time is the time of injection of the dye. The test is completed when the kidneys, ureters, and bladder show up on the X-ray. Although the dye is colorless, it makes the kidneys and ureters appear white on the X-ray so that they contrast with the background of the rest of the abdomen.
  • If, for example, the kidneys, ureters, and bladder can be seen after the 5-minute film is taken, then one last film will be taken immediately after you have urinated. If only one kidney and its ureter are seen after the 5-, 10-, and 20-minute pictures are taken, then the doctor will decide when further films should be taken. As a general rule, the interval for further films is determined by doubling the time from the last film. The time will be doubled until both kidneys and ureters can be seen.
  • For example, if only one kidney and its ureter are seen after the 20-minute picture is taken, then the next film will be done 40 minutes later. If the X-ray technician is still unable to see the kidneys after the 40-minute film, then the next test will be taken 80 minutes later.
• Between X-rays, you are usually taken back to the emergency department to rest on a stretcher.
  • While you are waiting for the X-rays to be taken, the nurses will check frequently to ensure that you are not experiencing any pain, nausea, or vomiting and, at the same time, will check your blood pressure, pulse, and breathing to make sure that these vital signs remain normal. If you have pain, nausea, or vomiting, the nurse can give appropriate medicines through the IV to help these symptoms.
  • Most hospitals allow you to be joined by family and friends during the waiting period.

After the X-rays are completed for the intravenous pyelogram, the doctor will review the films and discuss the findings with you and family members. If, for example, the doctor is unable to see both kidneys after a 4-hour picture, then you may have to be admitted to the hospital to continue further studies.

• The most common cause of obstruction to the flow of urine is a kidney stone. Other causes include masses, tumors, or cancers in adjacent tissues pressing against the ureter. Sometimes, bleeding from the kidney can produce a blood clot that can obstruct urine flow in the ureter. In older men, prostate enlargement can obstruct the flow of urine from the bladder as well as through the ureters.
• Following the test, the doctor might propose one of two courses of action: either waiting a few days for the stone to pass in the urine or referring to a urologist-a surgeon who specializes in diseases of the urinary tract.
  • If the IVP demonstrates a large obstructive stone located in the kidney or ureter, the urologist may use a lithotriptor-a machine that delivers sound waves-to shatter the stone into smaller particles that can pass through the ureter freely and out of the body in the urine.
  • Stones located in the lower part of the ureter above the bladder might need to be removed by a "basket" or laser technique. This requires that an instrument be inserted through the urethra (which is in the penis or above the vagina), through the bladder and then into the ureter where the stone can be snared with a small instrument and pulled into the bladder. Candidates for this procedure are people who have had the stone for many days and continue to have symptoms. The urologist's role is to ensure that the obstruction does not produce any kidney damage.

• If you are waiting for a stone to pass and your symptoms worsen, the doctor might order a repeat intravenous pyelogram to determine if the stone has changed location.
• If you are waiting to pass a stone, drink a lot of water to generate urine that will flush the stone through the ureters and into the bladder then out. The stone that passes out of the body through the urine can be easily captured if you urinate into a special cup that has a sieve at the bottom. The urine passes through the cup and into the toilet, and the stone (eventually, you hope) is trapped in the cup. Save the stone and take it to your doctor for analysis.
• If a procedure has been done to remove a stone, you will usually need to follow up with the urologist after a specified period of time.

If you are waiting for the "stone" to pass, and the pain worsens or vomiting is frequent enough that you cannot keep down pain medicine or fluids, call the doctor. Other warning signs include fever, chills, and seeing more blood in the urine.