Kidney stones are among the most painful and prevalent of urologic disorders. Several million kidney stones are diagnosed each year with an estimated 10% of the U.S. population destined to suffer the pain from a stone at some point in their lives. Fortunately, most stones will pass out of the body without any need for surgical intervention.
Kidney stones usually form when your urine becomes too concentrated. This causes minerals and other substances in urine to form crystals on the inner surfaces of your kidneys. Over time, these crystals may combine to form a small, hard mass, or stone.
The urinary tract is composed of the kidneys, ureters, bladder and urethra.
Your kidneys are two bean-shaped organs and are responsible for maintaining the balance by removing excess fluid, unneeded electrolytes and waste from your blood and converting it to urine. The kidney keeps a stable balance of salt and other substances in the blood. The kidneys also produce hormones that build strong bones and red blood cells. The urine is carried by narrow muscular tubes called ureters to the bladder and the bladder acts like a balloon that stretches and expands to store urine throughout the day.
A kidney stone forms in the kidney when there is an imbalance between certain chemicals in your urine that promote crystallization, especially calcium, oxalate, phosphate, uric acid and rarely, cystine - or the imbalance with substances that help prevent crystal formation, such as citrate and magnesium. Crystals also may form if your urine becomes too concentrated or is too acidic or too alkaline.
There are other stone types formed in children with special metabolic problems and struvite stones are usually present in patients with chronic urinary tract infection.
Scientists do not always know the reasons why stones form. These factors may increase your risk of developing stones:
For unknown reasons, the number of people in the U.S. with kidney stones has been increasing over the past 20 years. Caucasians are more likely to develop stones than African Americans and, although stones occur slightly more frequently in men, the number of women who get them has also been increasing over the past ten years. Kidney stones typically strike patients between the ages of 20 and 40 and, if a person forms a stone, there is a 50% chance over the next 3-5 years that they may develop another stone.
Certain foods may promote stones in susceptible people, but researchers do not believe that eating a specific item will cause stones in people who are not otherwise vulnerable.
Family or Personal History
A family or personal history of stones and other urinary infections and diseases certainly have a definite connection to stone formation. If someone in your family has kidney stones, you're more likely to develop stones too. And if you've already had one or more kidney stones, you're at increased risk of developing another.
Lack of Fluids
If you don't drink enough fluids, especially water, your urine is likely to have higher concentrations of substances that can form stones. That's also why you're more likely to form kidney stones if you live in a hot, dry climate, work in a hot environment, such as a commercial kitchen, or exercise strenuously without replacing lost fluids.
Rare, inherited diseases as well as more common disorders such as gout, chronic urinary tract infections and hyperparathyroidism can increase your risk of developing kidney stones.
Medications can have variable effects on stone formation. Consumption of calcium pills by a person who is at risk for forming stones, certain diuretics and calcium-based antacids may increase the risk of forming stones by increasing the amount of available calcium in the urine.
Usually the symptoms of a kidney stone start with extreme pain that has been described as being worse than child labor pains. The pain also begins suddenly as the stone moves in the urinary tract, causing irritation and blockage.
The pain, usually a sharp cramping pain, starts in your back or your side just under or below the edge of your ribs.
As the stone moves down the ureter toward your bladder, the pain may radiate to your lower abdomen, groin and genital structures on that side. In a man, the pain may move down to the tip of the penis.
Other symptoms may include:
Occasionally, stones do not produce any symptoms. They may be silent, but they also can be growing and causing irreversible damage to kidney function.
More commonly, if the stone is not large enough to prompt major symptoms, it can still trigger a dull ache that is often confused with muscle or intestinal pain. If the stone is too large to pass easily, pain continues as the muscles in the wall of the ureter try to squeeze the stone along toward the bladder.
Stones as small as 2-3 mm have caused symptoms while those as large as a pea may have quietly passed. If fever or chills accompany any of the above symptoms, you should be seen by your urologist immediately.
In general, stones are found on imaging studies and, in many cases, these are obtained for causes not related to stone disease. If stones are large, you should be referred to a urologist for evaluation.
Most often, kidney stones are found on an x-ray or ultrasound taken on someone who complains of blood in the urine or sudden pain. These diagnostic images give the doctor valuable information about the stone size and location, and blood and urine tests may also be obtained to help detect any abnormal substances that might promote stone formation.
If your doctor suspects a stone but is unable to make a diagnosis from a simple x-ray, other tests are certainly available.
These abdominal and pelvic CT scans, renal ultrasounds, and occasionally MRI studies help detect kidney stones or masses.
Treatment of kidney stones varies, depending largely on the size, position and number of stones in your kidney. Luckily, the majority of stones between 2-5 mm will pass without need for any surgical intervention. You should increase your daily fluid intake. Consuming 2-3 quarts of water increases urine production which will dilute the urine. Once stones have passed, no other treatment is usually necessary. We would like you to try to save any passed stones for chemical composition testing.
Renal colic or the sudden flank pain that occurs when small stones start down the ureter can be treated with bed rest and analgesics. Occasionally, you may need stronger pain killers for pain relief. Certain types of stones such as uric acid can be broken up with medical therapy that changes the level of acidity in the urine. The majority of stones are composed of calcium and cannot be dissolved.
Surgery should be reserved for cases of stones that:
Until recently, surgery to remove a stone was very painful and required an open surgical procedure with a long recovery time. Today, the treatment for stones is improved and many options do not require major surgery.
Stone removal procedures include:
How do I prevent kidney stones?
A good first step for you for stone prevention is to drink more liquids. Water is best and intake of greater than 2 quarts per day is best. If you tend to form stones, you should drink enough liquids throughout the day to produce at least 2 quarts of urine in every 24 hour period. People who form calcium stones do not necessarily need to restrict their dietary calcium or dairy products. Calcium supplements should be carefully employed and the best are usually calcium citrate such as Citracal or Caltrate. If you are at risk for developing stones, your doctor may also perform additional blood and urine tests to determine which factors can be altered to reduce the stone formation.
My stone has not passed, do I need surgery?
In general, you are facing surgery if your stones are too large and cause obstruction to the flow of urine. If your kidneys are blocked for a long period of time, irreversible loss of function may occur.
Will my children get kidney stones because I have them?
Any person with a family history of stones may be at higher risk for forming stones. Stone disease in a first degree relative, such as a parent or sibling, can dramatically increase the probability for you. In addition, more than 70% of people with certain rare hereditary disorders are prone to the problem. These conditions include cystinuria which is an excess of the amino acid, cystine, that does not dissolve in urine and, instead, forms stones composed of cystine. Also, primary hyperoxaluria is another rare genetic cause where the compound oxalate is present in high quantities in the urine and causes stone formation.
Are gallstones and kidney stones related?
No. There is no known link between gallstones and kidney stones. These stones are formed in different areas of the body. Also, if you have a gallstone, you are not necessarily more likely to develop kidney stones.
What is a staghorn stone?
Resembling the horns of a stag, these stones get their name from the shape they form by filling the entire kidney and renal pelvis with stones. Staghorn stones are linked to urinary tract infections. Despite the fact that they can grow large, they are often overlooked by patients because they sometimes cause minimal or no pain. A staghorn stone can lead to deterioration of kidney function, even without blocking the passage of urine; treating this condition can be challenging. In the past, urologists relied on conventional surgery and open stone removal. Today, urologists employ a combination of shockwave lithotripsy and percutaneous stone removal procedures, even though patients may still need an open procedure if the entire stone cannot be removed. You will need to work more diligently to prevent further stones from forming and work to keep urinary tract infections from occurring.
What experience does UINENY have treating kidney stones?
The Urological Institute of Northeastern New York (UINENY) and Dr. Mark White have a very large experience with treating both adult and pediatric stone disease. Our most common procedure is Holmium laser lithotripsy with over 1,400 adult patients and 100 children successfully treated over the past ten years. We also offer all forms of treatment for complex stone disease, including shockwave lithotripsy, percutaneous stone removal procedures and Holmium laser lithotripsy with the most up-to-date equipment.
For additional information on urological conditions, you may also contact the website www.urologyhealth.org.