FOR URGENT CARE OF A NEW KIDNEY STONE, GO TO YOUR CLOSEST EMERGENCY ROOM, AND ASK FOR A C-T SCAN.
TO SEE A WASHINGTON UNIVERSITY KIDNEY STONE EXPERT TO RELIEVE THE STONE OR TO PREVENT ANOTHER ONE, PHONE 314 362-8200
Sam B. Bhayani, MD
Alana Desai, MD
R. Sherburne Figenshau, MD
What are kidney stones?
Normally, urine has chemicals that prevent crystals from forming. But what happens when you start to have a pain in your back or side or you are having problems urinating? You could be one of the thousands of people with kidney stones.
Sometimes materials in the urine (dissolved substances like calcium and other matter) become concentrated in the urine and form solid crystals. These crystals can lead to stone development when material continues to build up around them, similar to the way a pearl is formed in an oyster.
Most stones contain calcium, but uric acid, cystine and struvite make up other types of stones.
Stones form and grow in the kidneys, and with time, they may move around within the organ. Some stones may be washed out of the kidney by urine flow and end up trapped within the ureter. Stones usually begin causing symptoms when this happens because they block the outflow of urine leading to the bladder.
Symptoms may be different, but most often, patients will complain of pain centered in their sides, which may also radiate toward the front of the abdomen or to the groin area. At times, the pain may become so severe that the patient becomes unable to find a comfortable position. Blood in the urine may also appear when a stone is present. In some patients, especially those with diabetes, a fever may develop from infected urine that becomes trapped behind a stone. This is a medical emergency because a bacterial infection that is not drained is a critical illness.
How prevalent is stone disease?
Approximately 10 percent of men and 3 percent of women are affected – usually in their 20s to 40s. Of these patients, at least 50 percent will have a recurrence within ten years of their first stone, unless the disease cycle can be interrupted.
What are risk factors for kidney stones?
High protein diet
High salt diet
Family history of stones
What kind of treatment is available?
There are a few different ways to treat kidney stones, depending upon the patient’s medical condition, where the stones are, how big the stones are, and sometimes, what the stone consists of.
Shock wave lithotripsy (SWL) - This is a completely non-invasive form of treatment in which an energy source produces a shock wave that is directed at a urinary stone within the kidney or ureter. Shock waves go through the patient either through a water bath, in which the patient is placed, or using a water-filled cushion that is placed against the skin.
* Adapted from the American Urological Society. (link to AUA web site: http://www.urologyhealth.org/adult/index.cfm?cat=12&topic=105)
Ultrasound or fluoroscopy is used to locate the stone and focus the shock waves. The repeated force of the shock waves breaks the stone apart into small pieces.
Usually SWL is performed with the patient under heavy sedation, although sometimes general anesthesia is used. Once the treatment is completed, the small stone particles then pass down the ureter and eventually are urinated away.
Sometimes, the doctor has to place a stent in the ureter to help the stone pieces drain. A stent is a device that resembles a straw – it holds the ureter open and keeps the stone from scraping against the sides of the ureter.
Patients who have this procedure usually go home the same day and can get back to normal activity within two to three days.
Ureteroscopy - This treatment involves the use of a very small, fiber-optic instrument called a ureteroscope, which allows access to the stones in the ureter or the kidney. It allows the urologist to look directly at the stone by moving the camera on the end of the scope up the ureter by way of the bladder. No incisions are necessary, but general anesthesia is used.
Once the stone is seen through the ureteroscope, a small basket-like device can be used to grab the smaller stones and remove them. If a stone is too big to remove, a laser, spark-generating probe or air-driven probe can be passed through the ureteroscope and the stone can be crushed.
If the doctor has to do much maneuvering to crush the stone, a stent may be placed to allow the swelling to go away.
Patients normally go home the same day and can get back to normal activities in two to three days.
Percutaneous nephrolithotomy (PNL) - PNL is the treatment of choice for large stones within the kidney that can’t be effectively treated with lithotripsy or ureteroscopy.
The procedure is performed with the patient under general anesthesia. The main advantage of PNL, when compared with traditional open surgery, is that only a small incision (smaller than an inch) is required in the side.
The urologist then places a guide wire through the incision; the wire is inserted into the kidney under radiologic guidance and then directed down the ureter. A passage is created around the wire with dilators providing access into the kidney.
An instrument called a nephroscope is then passed into the kidney to look at the stone. Using an ultrasonic probe or a laser, the stone is pulverized. Because the tract allows passage of larger instruments, the urologist can suction out or grab the stone fragments. This results in a higher clearance of stone fragments than with lithotripsy or ureteroscopy.
Once the procedure is done, a tube is left in the side to drain the kidney for several days. Most PNL patients spend two to three days in the hospital.
Open Surgery An incision is required to see the kidney or portion of ureter that is involved with the stone. The portion of the kidney overlying the stone or the ureteral wall is then surgically cut, and the stone is removed. This type of surgery is only used for very complicated cases of stone disease.
There is a risk of blood loss, infection or injury to the bowel or other organs or urinary vasculature. In most cases, patients do not require blood transfusion. Because this procedure is the most invasive and painful of the stone surgical treatments, patients often spend five to seven days in the hospital, and it may take six weeks before normal activities can be resumed.
Postoperatively, blood and urine tests may be done to determine risk factors for stone formation. Patients who have kidney stones have a 50 percent chance of redeveloping a stone within five years.