American Medical Association Family Medical Guide - American Medical Association [532]
Voiding Cystourethrogram
A voiding cystourethrogram is an X-ray procedure that allows a doctor to evaluate bladder function during urination. This test is usually performed to diagnose anatomical problems that may be the underlying cause of conditions such as vesicoureteral reflux, in which urine in the bladder is forced back up through the ureters toward the kidneys instead of down through the urethra and out of the body. The procedure is usually performed on an outpatient basis.
As you lie on your back, a catheter (a thin, flexible tube) is inserted through your urethra and into the bladder. After the catheter is in place, the doctor injects fluid containing a contrast medium (dye) into your bladder through the catheter. Several X-rays are taken while your bladder is being filled with the fluid. After the catheter has been removed, the doctor will ask you to urinate into a handheld urinal or bedpan. Additional X-rays are taken as you empty your bladder.
Although most voiding cystourethrograms do not cause problems, there is a small risk of infection or an allergic reaction to the contrast medium. Also, for a few hours after the catheter has been removed, some people experience temporary irritation of the urethra that causes a slight burning sensation while urinating. If you have persistent burning or pain when urinating, tell your doctor; these could be symptoms of a bladder infection.
Cystoscopy
In cystoscopy, a doctor inserts a viewing tube called a cystoscope through the urethra and into the bladder. A tiny light and camera at the tip of the cystoscope allow the doctor to view the bladder directly or on a video monitor.
Chronic Pyelonephritis
Chronic pyelonephritis is a recurring kidney infection that causes progressive scarring of kidney tissue over a period of several years. Doctors think the condition begins in childhood and persists undetected into adulthood. After years of scarring, symptoms of kidney disease, including chronic kidney failure (see page 817), may develop.
The bacteria that cause chronic pyelonephritis probably enter the urinary tract through the urethra (the tube that carries urine from the bladder out of the body). The infection is usually limited to the lower parts of the urinary tract, because the outflow of urine and the valvelike openings between the ureters and the bladder normally keep the bacteria from spreading upward. When a healthy person urinates, the bladder contracts and forces urine out of the body through the urethra. At the same time, the openings between the ureters and the bladder close like valves, preventing urine from flowing back into the kidneys. However, in some cases, this valvelike action does not work properly and, when the bladder contracts, urine is forced up through the ureters and back into the kidneys. This backward flow is called vesicoureteral reflux.
Doctors think that a combination of recurring infections and reflux probably causes chronic pyelonephritis in most people who develop the condition. Kidney stones (see page 814) also may cause the disorder by blocking the normal flow of urine and providing a reservoir for bacteria. In some people, chronic pyelonephritis may be preceded by repeated episodes of other urinary tract infections, such as acute pyelonephritis (see page 804) or cystitis (see next page). However, doctors do not think that these infections cause chronic pyelonephritis.
The flow of urine
A possible cause of kidney infection is ineffective closing of the valvelike openings between the ureters and the bladder. If the openings between the ureters