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Hard facts about kidney stones

March 08, 2016 | UCI Health
Two kidneys with a kidney stone in the right kidney

The pain, says anyone who has had them, is excruciating.

Kidney stones are one of the most common disorders of the urinary tract. Each year in the U.S., they cause more than 300,000 people to seek diagnosis and relief at an emergency room.

Dr. Ralph Clayman, UCI Health urologist and a pioneer in minimally invasive treatment of kidney disease, and other specialists at the UCI Health Center for Urological Care are working to reduce the frequency and impact of kidney disease and its associated health problems.

But what are kidney stones, exactly? Who gets them and why?

What are kidney stones?

Kidney stones consist of highly concentrated substances normally found in urine, such as calcium, oxalate and phosphorus, says Clayman. Insufficient fluid intake allows these minerals to crystalize in the kidneys and bind together, forming stones.

Here are some other basic facts about kidney stones:

  • Kidney stones may be smooth or jagged, and they are usually yellow or brown. Stones may be as small as a grain of sand or as large as a pea. Some stones are even as big as golf balls.
  • Most kidney stones pass out of the body with urine. A larger stone may get stuck and block the flow of urine, causing pain and kidney damage.
  • Symptoms such as fever and chills, vomiting, blood in the urine, extreme back or side pain that doesn’t go away may signal a kidney stone in need of immediate medical attention.

Kidney stone risk factors

One cause is hypercalciuria, a condition that runs in families in which urine contains unusually large amounts of calcium. Recurrent urinary tract infections are another cause.

But the single, most important culprit is not drinking enough water, says Clayman, who is also former dean of the UCI Health School of Medicine. “If everybody drank three quarts of water a day,” he said, “I’d have to retire because I’d have nothing to do. It’s truly a problem due to too little fluid intake.”

People who should take extra care to drink enough fluids include those who have:

  • Had a previous kidney stone
  • A family history of kidney stones
  • A diet high in animal protein or containing too much salt
  • High blood pressure
  • Type 2 diabetes
  • Illnesses requiring certain medications, such as diuretics, which help remove fluid from the body; the protease inhibitor indinavir (Crixivan), a medication used to treat HIV infection; and the anti-seizure medication topiramate (Topamax).

Treating kidney stones

Treatment for kidney stones ranges from a noninvasive shockwave therapy that pulverizes smaller stones, to an inpatient procedure that involves a small puncture in the back to reach into the kidney and remove the stones using lasers and other devices.

The options will depend on the size of the kidney stones and what they are made of, as well as whether they are causing pain or obstructing the urinary tract.  

One thing that is clear is that at UC Irvine, open surgery for kidney stones is something of the past. Clayman notes that he and his fellow UCI Health urologists have not had to operate on a kidney stone in more than a decade.

Preventing a recurrence

When advising patients on how to prevent a recurrence of kidney stones, Clayman doesn’t prescribe medication as a first-line approach.

He prefers touting the benefits of:

  • Consuming normal levels of calcium
  • Drinking three quarts of fluid a day and
  • Following a low-salt diet (2 to 3 grams per day)
  • Following a low animal protein diet (fewer than 50 grams per day)

“With increased fluid intake and a simple diet, most people can prevent a stone recurrence,” he said.

Learn more about kidney stones


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