Kidney Stones


Ever heard of kidney stones?  No, they’re not those rounded landscape pavers in your yard that you trip over when you’re carrying in the groceries.  They’re much worse than that.  Kidney stones are small, hard mineral deposits that can form inside your kidneys.  They consist of mineral and acid salts.  It has been said that passing a kidney stone can cause some of the worst pain imaginable.  Even though most are small, they generally have rough or jagged surfaces.  Ouch!

Kidney stones have many causes and can affect any part of the urinary tract — from the kidneys to the bladder.  (We’ll look at causes a little later.)  True, they can bring considerable pain, but kidney stones usually cause no permanent damage.  Depending on the size and location, the stone might pass through the urinary tract as a result of lots of water, pain medication, and patience.  In other instances, surgery might be needed.

If you have a kidney stone and it doesn’t move in your kidney or make its way into your ureter (the tube which connects your kidney to your bladder), you may not know you have it — until it moves.  Then you may experience any number of unpleasant symptoms, including severe pain in the side and back (below the ribs), pain that spreads to the lower abdomen and groin, pain that comes in waves and fluctuates in intensity, pain that’s so severe that you can’t sit still or find a comfortable position, and/or pain when you urinate.  The pain may move with the movement of the stone.  If that’s not enough, you may also experience nausea and vomiting with the pain.  You may feel chills and fever if an infection is present.  And your urine may be a different color; it may be pink, red (bloody), brown, or cloudy.  It may smell bad.  Your urination habits may change; you may have the urge to go more frequently but with less output each time.

It’s a good idea to rule out other conditions, so if you experience any of the above symptoms, get checked out right away.  Sudden, severe back or belly pain can be associated with appendicitis and ectopic pregnancy.  Painful urination is also a common symptom of a urinary tract infection or an STD.

Kidney stones are diagnosed in a number of ways.  A blood test can reveal too much calcium or uric acid in your blood.  A 24-hour urine collection test may show that you’re excreting too many stone-forming minerals or too few stone-preventing substances.  There are a lot of imaging test options, including simple abdominal X-rays, CT scans, ultrasound, and intravenous urography, which involves injecting dye and taking X-rays.

When a kidney stone is diagnosed, how is it treated?  The good news is that most stones won’t require invasive treatment.  Small stones with minimal symptoms may be passed by drinking lots of water and taking pain medication until it passes.  Your healthcare provider may also prescribe an alpha blocker, which will relax the muscles in your ureter, helping you to pass the stone more quickly and with less pain.

With larger stones, there are more potential problems — bleeding, kidney damage, frequent urinary tract infections — but also more options for treatment.  Your doctor may break up the stone using sound waves.  It’s called extracorporeal shock wave lithotripsy (ESWL), and it’s the most common medical procedure for treating large kidney stones.  The sound waves break the stones into tiny pieces that can be passed in the urine.  There’s also the use of a thin lighted tube with a camera in it (amazing, isn’t it?) that the doctor can insert through the urethra and bladder to the ureter.  Once the stone is located, it is either captured and removed or broken up to be passed in the urine.  Some very large stones will require surgery, but it is performed with small telescopes and instruments inserted through a small incision in the patient’s back.

So what causes kidney stones?  Typically they form when your urine contains more crystal-forming substances (calcium, oxalate, and uric acid) than the fluid in your urine can dilute.  The urine becomes so concentrated that crystals form.  The causes can range from simple long-term dehydration — not drinking enough water each day — to a family predisposition to kidney stones, an excess of calcium or certain other minerals in the diet (sometimes due to geographic soil or water conditions), a urinary infection, a diet of fruits and vegetables high in oxalate (examples:  rhubarb, Swiss chard, dark leafy greens, okra, sweet potatoes, beans, berries, oranges, nuts, instant coffee, tea, chocolate, soy products, tofu), a diet high in protein, sugar, and especially sodium, living in a hot climate that causes sweating and loss of fluids, being obese, or possibly just leading a sedentary lifestyle.


White men, particularly after the age of 40, have a greater risk for kidney stones than other groups.  Women see their risk rise after age 50.  High blood pressure, gout, and urinary infections boost the risk also.  You should ask your healthcare provider about possible risk associated with calcium supplements.

How can kidney stones be prevented?  The easiest way is to drink water throughout the day, every day.  For people with a history of kidney stones, doctors usually recommend passing about 2.6 quarts of urine a day.  So you’ll need to drink at least that much water to keep your urine light and clear.  That’s a lot of water — about 10 1/2 eight-ounce glasses.  Eat fewer oxalate-rich foods (see above), and eat a diet low in sodium and animal protein.

Kidney stones are no fun, so it might pay to take steps to make sure you don’t experience one, especially if your family has a history of them.  But if you should be one of the unfortunate ones who gets a kidney stone, just remember the old adage, “This too shall pass.”

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