Insurance
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What Are Kidney Stones?
by Samuel Snyder, D. O.
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NEPHROLOGY
What do kidneys do?
Kidney stones
Kidneys and salt
Kidneys and bones
Chronic Kidney Disease
Dialysis
Diabetes
Transplant
Nephrology team
Protein in the diet
Kidneys disease
and the heart
Kidney disease and sex
Hypertension
Anemia
Acute Renal Failure
Polycystic disease
ENDOCRINOLOGY
Diabetes Type I
Diabetes Type II
Diabetes treatment
PSYCHIATRY
Stress
UROLOGY
Benign Prostatic Hyperplasia
Erectile Dysfunction
CARDIOLOGY
Myocardia Infarction
Congestive Heart Failure
Acute Coronary Syndrome
Cholesterol
GASTROENTEROLOGY
Gastroesophageal Reflux Disease
Peptic Ulcer Disease
Often, there is an inborn, or congenital, tendency for stone formation, which finally brings a stone about because of a change in some environmental factor. There are several different types of stones. The most common contain calcium and oxalate, but uric acid and phosphate are also important components of stones; and uncommonly, some families have a predisposition for stones containing cysteine. Chronic infections of the kidneys may lead to a type of stones called “staghorns”—so named for the shape they assume within the kidney’s drainage system; and these can actually obstruct the outflow of urine. Sometimes individuals with disease of the parathyroid glands, located in the neck, form kidney stones, because these glands help regulate normal calcium metabolism. In addition, individuals with inflammatory bowel disease, such as Crohn’s disease, have an increased tendency to get stones.
Stones be very small or quite large. A small stone, less than a millimeter, might pass with little or no discomfort. Similarly, stones that are too large to pass out of the kidney might never cause pain. Stones may be present for a long period of time, forming slowly. But when the stone begins to pass from the kidney down the ureter—the tube which drains the kidney to the bladder—or moves from the ureter into the bladder, that’s when the pain occurs. It might be in the flank, or radiate into the groin or even into the sex organs. Occasionally, a person might seen blood in the urine, as the stone traumatizes the delicate tissue of the ureter. The pain can be extremely intense, prompting a trip to the emergency room.
Whenever possible, it is preferable to allow the stone to pass. Most of the stones (90%) that are less than 2 mm will pass spontaneously. Flushing stones with increased fluid intake helps the passage of the stone. Pain may need to be treated with oral medications. As long as pain can be kept to tolerable levels, allowing the stones to pass is desirable.
However, only half of the stones 4 mm or greater will pass on their own. For these, different approaches are needed.
Depending on the position and size of the size of the stone, a number of possibilities are available. For a small stone that has passed at least half way down the ureter, a urologist may be able to retrieve the stone by passing a catheter via the urethra, into the ureter, and capture the stone in a basket at the tip of the catheter.
For a large stone that has not progressed down the ureter, an option is extracorporeal shock wave lithotripsy (ESWL). In this procedure, ultrasonic waves are directed at the stone, and shock it into small fragments which can then pass through the ureter. This procedure requires anesthesia, and patients may have pain for some time, as they pass stone fragments, and as shocked tissue recovers.
Occasionally, surgery is necessary. If a stone is obstructing outflow of urine, particularly in an individual with only one kidney, or with a transplanted kidney, or if pain is extreme and cannot be controlled in any other way, a surgeon might have to open the kidney surgically to remove the stone. This is called a nephrolithotomy or ureterolithotomy, depending on the stone location. This clearly requires general anesthesia, and has a longer recovery period than the other procedures discussed.
Finally, a hybrid procedure has been developed, called nephrolithotripsy. In this procedure, a special catheter is passed through the patient’s flank, through the kidney, into the ureter. The catheter then emits the same ultrasound shock waves used in ESWL to break up a stone in the ureter. Fragments are then passed through the ureter with the passing of urine.
All of the above methods are effective for treating a serious episode of kidney stones. The problem is—what if you have repeated episodes? How many times can these procedures be performed? The real answer to this question is prevention.
The most important thing that can be done to prevent stones is to keep those minerals in solution. This means to drink generous amounts of water, so the concentration of the minerals stays relatively low. For those who have had one or more stones already, they should drink enough water to make 2½ to 3 quarts of water daily. This means drinking about 3 to 4 quarts of water.
For those who have calcium based stones—at least three quarters of all stones—the second most important thing to do is to restrict salt intake (see article on Salt). The more salt a person eats, the more likely they are to have calcium stones; and salt restriction can reduce the risk of stone recurrence.
Many individuals benefit from keeping urine relatively alkaline, since stones form more easily in acid urine. Doctors occasionally prescribe citrate solutions in order to keep urine alkaline and prevent minerals from crystallizing.
For those with stones composed of oxalate, diets that are low in this compound may reduce repeat episodes. These foods include dark greens, chocolates and certain nuts and beans, such as almonds, soy beans, peanuts, pecans, and baked beans.
Although these steps to prevent stone formation require changes in lifestyle, results prove that an ounce of prevention is worth a pound of cure.