0:00:08.243,0:00:12.673
The biggest kidney stone on record[br]weighed more than a kilogram

0:00:12.673,0:00:16.765
and was 17 centimeters in diameter.

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The patient didn't actually[br]swallow a stone the size of a coconut.

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Kidney stones form inside the body,

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but unfortunately, they're extremely[br]painful to get out.

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A kidney stone is a hard mass[br]of crystals that can form in the kidneys,

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ureters,

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bladder,

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or urethra.

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Urine contains compounds [br]that consist of calcium,

0:00:39.595,0:00:40.485
sodium,

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potassium,

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oxalate,

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uric acid,

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and phosphate.

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If the levels of these particles[br]get too high,

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or if urine becomes too acidic[br]or basic,

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the particles can clump together[br]and crystallize.

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Unless the problem is addressed,

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the crystals will gradually grow[br]over a few weeks, months, or even years,

0:01:03.907,0:01:08.116
forming a detectable stone.

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Calcium oxalate is the most common[br]type of crystal to form this way,

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and accounts for about [br]80% of kidney stones.

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Less common kidney stones are made[br]of calcium phosphate, or uric acid.

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A slightly different type of stone

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made of the minerals magnesium[br]ammonium phosphate, or struvite,

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can be caused by bacterial infection.

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And even rarer stones can result[br]from genetic disorders

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or certain medications.

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A kidney stone can go undetected[br]until it starts to move.

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When a stone travels[br]through the kidney and into the ureter,

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its sharp edges scratch[br]the walls of the urinary tract.

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Nerve endings embedded in this tissue[br]transmit excruciating pain signals

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through the nervous system.

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And the scratches can send blood flowing[br]into the urine.

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This can be accompanied [br]by symptoms of nausea,

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vomiting,

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and a burning sensation while urinating.

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If a stone gets big enough[br]to actually block the flow of urine,

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it can create an infection,[br]or back flow,

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and damage the kidneys themselves.

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But most kidney stones [br]don't become this serious,

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or even require invasive treatment.

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Masses less than five millimeters[br]in diameter

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will usually pass out [br]of the body on their own.

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A doctor will often simply recommend[br]drinking large amounts of water

0:02:37.415,0:02:39.895
to help speed the process along,

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and maybe taking some pain killers.

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If the stone is slightly larger,[br]medications like alpha blockers

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can help by relaxing the muscles[br]in the ureter

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and making it easier [br]for the stone to get through.

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Another medication called[br]potassium citrate

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can help dissolve the stones by creating[br]a less acidic urine.

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For medium-sized stones up to about[br]ten millimeters,

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one option is pulverizing them[br]with soundwaves.

0:03:10.577,0:03:16.226
Extracorporeal shock wave lithotripsy[br]uses high-intensity pulses

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of focused ultrasonic energy[br]aimed directly at the stone.

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The pulses create vibrations inside[br]the stone itself

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and small bubbles jostle it.

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These combined forces crush the stone[br]into smaller pieces

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that can pass out of the body more easily.

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But zapping a stone with sound[br]doesn't work as well

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if it's simply too big.

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So sometimes, more invasive[br]treatments are necessary.

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A rigid tube called a stent[br]can be placed in the ureter to expand it.

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Optical fibers can deliver laser pulses[br]to break up the stone.

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Stones can also be surgically removed[br]through an incision

0:04:00.980,0:04:04.489
in the patient's back or groin.

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What about just avoiding kidney stones[br]in the first place?

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For people prone to them,

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their doctor may recommend[br]drinking plenty of water,

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which dilutes the calcium oxalate[br]and other compounds

0:04:15.651,0:04:20.615
that eventually build up [br]into painful stones.

0:04:20.615,0:04:21.878
Foods like potato chips,

0:04:21.878,0:04:22.932
spinach,

0:04:22.932,0:04:23.744
rhubarb,

0:04:23.744,0:04:26.280
and beets are high in oxalate,

0:04:26.280,0:04:29.847
so doctors might advise limiting them.

0:04:29.847,0:04:32.432
Even though calcium [br]is often found in stones,

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calcium in foods and beverages[br]can actually help

0:04:36.281,0:04:39.101
by binding to oxalate [br]in the digestive tract

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before it can be absorbed[br]and reach the kidneys.

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If you do end up with a kidney stone,[br]you're not alone.

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Data suggests that rates are rising,

0:04:48.913,0:04:52.852
but that world record probably[br]won't be broken any time soon.