When is a Whitaker test needed?
Physicians recommend a Whitaker test for selected patients who have upper urinary tract dilation (enlargement), but in whom it is not clear if the condition is caused by a blockage. This test can help your child's physician determine if surgery is required.
How does it work?
If fluid is infused into the kidney faster than it can pass through a blockage, the pressure inside the kidney will rise and the pressure in the bladder will stay the same or fall.
In a Whitaker Test, the pressure inside both organs is measured at the same time, allowing the radiologist to detect even mild blockages. Antegrade pyelography, another interventional radiology procedure that visualizes contrast flowing from the kidney into the ureter and bladder, is an integral part of the Whitaker Test.
How should I prepare my child for the procedure?
Explain to your child in simple terms why the treatment is needed and what will happen. You can say that you will be close by and that she may bring a favorite toy or blanket into the procedure room.
What will happen before the Whitaker test?
Someone from the hospital will call you a few days before the test to tell you where to go when you come to the hospital. The staff member will talk about when your child should stop eating, drinking and taking medicines.
When you arrive at the hospital for the procedure:
- The interventional radiologist will talk to you about the procedure and ask you to sign the consent form. (You must be your child's legal guardian to sign this form. If you are a legal guardian and not a parent, you must bring the paperwork showing proof of legal guardianship.)
- An anesthesiologist will explain the anesthetic plan and ask you to sign a separate consent form.
- Your child will change into a hospital gown.
- A nurse or anesthesiologist may start an intravenous (IV) line.
- Once your child is asleep, you will be escorted to a special waiting area.
What happens during the procedure?
- Your child will be positioned on an angiographic table and placed under general anesthesia.
- The nurse will insert a small, soft tube into your child's bladder.
- Your child will be positioned prone (on the stomach), and the kidneys will be examined with an ultrasound probe.
- The technologist will clean the skin of your child's back with a special iodine solution and places sterile drapes to prevent infection.
- The radiologist will insert a local anesthetic (numbing medicine) into the skin and then places a thin needle into the kidney, using the ultrasound images for guidance.
- The radiologist uses the needle to deliver contrast material into the kidney at a specific rate.
- Pressures are measured through the needle in the kidney and the catheter in the bladder.
At the end of the procedure, the needle and catheter are removed and a small bandage is applied where the needle was inserted. Occasionally, in cases where significant obstruction is found, the radiologist will place an indwelling catheter (nephrostomy tube) in the kidney through the initial puncture site. This will allow urine to drain until your child's medical team can formulate a plan to treat the obstruction.
What happens after the Whitaker test?
Your child will be taken to the recovery room, where we will closely monitor him. You may be with your child in the recovery room.
How will I learn the results?
The interventional radiologist will speak with you after the procedure and explain the findings and results.
Is it safe?
When performed by an appropriately trained and experienced interventional radiologist, the Whitaker test is safe. As the procedure is performed under general anesthesia, your child will feel no discomfort. There may be some mild discomfort at the puncture sites after the procedure.
During the Whitaker test, your child will be exposed to ionizing radiation (x-rays). While we always attempt to minimize exposure to x-rays, we believe that the benefit of an accurate diagnosis outweighs the exposure that occurs during the procedure. Because children are more sensitive to radiation exposure than adults, we have been leaders in adjusting equipment and procedures to deliver the lowest possible dose to young patients.