When David saw the kidney stone he had passed, he understood why he had suffered so much pain. It was a hard deposit, nearly half an inch in diameter, and it took lots of water, pain medication and effort to get it through his urinary tubes. Now, he is fine, but he wants to make sure it doesn’t happen again.
Kidney stones, comprised of mineral and acid salts, come in many sizes and sometimes are formed and passed without causing any symptoms. Even a large stone such as David’s usually does not cause lasting damage.
Unfortunately, if you have had one stone, you’re more likely to have another–whether because of your family history or your lifestyle. They usually occur when your urine becomes overly concentrated, giving minerals an opportunity to crystalize and stick together.
Inside the kidney, a stone may cause no symptoms unless it becomes infected, as it sometimes does. Otherwise, it may go unnoticed until it starts to move around within the kidney or starts to pass into the ureter–the small tube that connects the kidney and the bladder.
Even a small stone in the ureter can cause urine to back up, resulting in pressure and pain that can sometimes be excruciating. Often referred to as renal colic, because it comes in spasms, it has been compared to the pain of childbirth.
The pain typically starts in the side or back just below the ribs and often spreads to the lower abdomen or groin. Intermittent pain can make the person writhe in an effort to find a comfortable position, either sitting or standing. Vomiting and nausea may occur, plus chills and fever if there is an infection.
Other symptoms include
• pain when passing urine;
• urine that is cloudy or foul-smelling;
• pink, brown or red urine;
• frequent and urgent urination.
Must Rule Out Other Problems
These symptoms are likely to prompt a visit to a doctor, and the first order of business is usually pain control. The doctor must rule out more serious problems such as an aortic aneurysm, appendicitis, gall bladder disease or diverticulitis. In a male, the symptoms could also be caused by torsion of the testicles. A urinalysis may be needed to see if there is an infection.
Imaging of the kidney is usually required to confirm a diagnosis. To avoid excessive radiation exposure, ultrasound might be favored over a CT scan.
A large stone that causes continuing obstruction can lead to an infection or even kidney failure. Such cases may require surgery or lithotripsy, a procedure that uses high-energy shock waves to break up the stone.
If no complications are found, the patient may be sent home to pass the stone. This may require two or three weeks or longer with pain medication and instructions to drink a lot of water.
Once the stone passes through to the bladder, the pressure is relieved. And final passage of the stone is usually uneventful since the tubes leading out of the bladder, the urethra, are larger in diameter than the ureters.
The biggest worry at that point is recurrence, and persons who have had one kidney stone of the most common type have a 50 percent chance of suffering another within 10 years. Measures taken to prevent recurrence are many of the same things that might be effective in heading off a first kidney stone.
DRINK PLENTY OF FLUIDS: The less you drink, the more concentrated your urine becomes, creating an environment favorable to the development of stones.
If your urine usually has a dark appearance, you are not drinking enough. A healthy color is very light yellow to clear.
For good health and prevention of a first kidney stone, doctors recommend about 8 to 12 glasses a day. If you exercise or if the weather is hot, you need more. Water is best because it contains no calories, sugar or caffeine.
For persons wanting to avoid recurrence, aggressive dilution of urine is recommended. This means drinking enough to eliminate at least two liters of water through urine every day.
CUT BACK ON SALT: The most common type of kidney stone, a calcium oxalate stone, occurs when oxalate, a by-product of foods such as rhubarb, spinach, beets, peanuts, chocolate and sweet potatoes, binds to calcium as urine is being made by the kidneys. Too much salt and too little water tend to increase levels of both oxalate and calcium in the kidneys.
Pushing the salt shaker away is no solution. Most of the sodium in our diet comes from processed, prepared and restaurant foods. All deli meat is high in sodium unless labeled otherwise. A slice of turkey or chicken probably contains as much sodium as a slice of ham.
LOSE WEIGHT: Several studies have found an association between kidney stones and the metabolic syndrome, characterized by abdominal obesity, type 2 diabetes, high blood pressure and high cholesterol.
Although weight loss might reduce your risk of developing a kidney stone, don’t lose weight through a high-protein diet. The second most common type of stone is a uric acid stone, and too much protein causes the urine to have a high uric acid content. To head off recurrence of stone formation, no more than 12 ounces of animal protein per day is recommended.
One study found the DASH diet, high in fruits, vegetables and low-fat dairy products, to be effective in preventing kidney stone recurrence. However, large intake of whole grain foods, as recommended by this diet, was found to increase the risk of stones.
EAT YOUR CALCIUM, AVOID SUPPLEMENTS: The Women’s Health Initiative and the Nurses’ Health Study both found that women taking calcium supplements had a higher risk of developing kidney stones. Getting calcium through food, however, does not appear to increase risk and may protect against them.
One study of 22,000 men, found that those who took higher than recommended doses of vitamin C–seven 1,000 milligram tablets or more a week–doubled their risk of developing a kidney stone. No increased risk was found for eating foods high in vitamin C.
The development of kidney stones is a complex process that is not fully understood. What works for one person might not be effective for someone else. To help them determine a preventive strategy, doctors often do 24-hour urine studies to measure urine volume and levels of calcium, sodium, citrate, uric acid and other compounds.
REFERENCES:
R. Todd Alexander, et al, “Kidney stones and kidney function loss: a cohort study,” BMJ, August 30, 2012.
Will Boggs, M.D., “DASH diet might reduce recurrent kidney stones,” Reuters Health, March 10, 2014 (American Journal of Kidney Diseases, 2014;63:456-463.
David Douglas, “Simple score gauges chances of kidney stones,” Reuters Health, April 22, 2014.
Marcia Frelick, “Kidney stones: new tool may predict recurrence,” Medscape Medical News, August 13, 2014 (Journal of the American Society of Nephology, August 7, 2014).
Sandra Adamson Fryhofer, M.D., “Can vitamin C cause kidney stones?” Medscape Internal Medicine, May 21, 2014.
Miranda Hitti, “Hotter climate may mean more kidney stones,” WebMD Health News, July 15, 2008.
Yasuro Kohjimoto, M.D., Ph.D., et al, “Association of metabolic syndrome traits and severity of kidney stones: results from a nationwide survey on Urolithiasis in Japan,” American Journal of Kidney Disease, 2013;61(6):923-929.
Christy Krieg, “The role of diet in the prevention of common kidney stones,” Urological Nursing, 2005;25(6):451-456.
Mayo Clinic Staff, “Kidney stones,” MayoClinic.com, March 17, 2012.
National Kidney Foundation, “Kidney stones,” 2014.
Robert Preidt, “Will kidney stones recur? New test might tell,” WebMD, August 7, 2014.
Steve Stiles, “Kidney stones may up CHD risk in women, but not men,” Medscape, July 13, 2013.
Benjamin Wedro, M.D., “Kidney stones,” MedicineNet.com, 2014.
12/19/2014
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