American Medical Association Family Medical Guide - American Medical Association [541]
There is no effective treatment for most kidney stones that have already formed. However, if your body forms stones made of uric acid, your doctor may prescribe drugs that can prevent more stones from forming or, sometimes, dissolve existing stones. Doctors prescribe thiazide diuretics for people whose stones are caused by excessive excretion of calcium in the urine. If a stone causes a blockage in the lower third of the ureter, it can sometimes be removed during a procedure called cystoscopy (see page 805), in which a doctor passes tiny instruments through a cystoscope (viewing tube) into the bladder and up into the ureter, where the stone is trapped. When the doctor withdraws the instrument, the stone often comes out with it. The doctor can also pass a smaller viewing tube called a ureteroscope into the ureter to remove the stone or crush it with a laser (a highly concentrated beam of light) or ultrasonic probe passed through the ureteroscope.
Stones in the upper part of the ureter or in the kidney may be crushed using a technique called extracorporeal lithotripsy, in which a machine called a lithotriptor produces shock waves that pulverize the stones into a powder that can pass out of the body in urine. Lithotripsy has made surgery for kidney stones unnecessary in most cases.
In rare cases, stones severely damage one of the kidneys, and the entire kidney may need to be removed. The healthy remaining kidney increases in size and level of function and does the work of both kidneys.
Extracorporeal lithotripsy
Extracorporeal lithotripsy is a procedure used to destroy kidney stones. A machine called a lithotriptor, which is placed against the abdomen, generates a shock wave that passes through the body to the stone, causing it to disintegrate into a powder that passes from the body in urine.
Bladder Stones
A kidney stone (see page 814) that has traveled through one of the ureters (the tubes that connect the kidney and the bladder) into the bladder is usually relatively small and will pass easily out of the body through the urethra. Stones that form inside the bladder, however, tend to be larger than kidney stones and may remain in the bladder. These stones form when the bladder does not empty properly, such as when the opening into the urethra is obstructed by an enlarged prostate gland (see page 832).
Symptoms
A bladder stone may cause symptoms such as a frequent urge to urinate, pain when you pass urine, an intermittent stream of urine, or blood in the urine. Often the blood seems to be squeezed out in the last few drops of urine.
Diagnosis
If you have symptoms of a bladder stone, your doctor will examine you and order a urine test to check for bacteria and white blood cells, which are signs of infection. He or she may also order an abdominal X-ray (see page 109), a CT scan (see page 112), or an ultrasound scan (see page 111) to examine your bladder.
Treatment
If you have bladder stones that are too large to pass naturally through the urethra, the doctor must remove them. This is usually performed by passing a cystoscope (viewing tube) up the urethra into the bladder. The stones are then either crushed and removed, or they are removed in one piece through the cystoscope. To crush the stones, a doctor may use a laser (a highly concentrated beam of light) or an ultrasonic probe passed through a cystoscope, or shock waves in a technique called extracorporeal lithotripsy (see illustration at left). In some cases, very large stones may need to be removed with surgery in which the bladder is opened. After the stone is removed, the doctor will try to find the cause of the stone and recommend treatment to prevent additional stones from forming.
Kidney Failure
Kidney failure, also called renal failure, occurs in one of three forms: acute, chronic, or end stage. Acute kidney failure is a condition in which