Placeholder Image

Subtitles section Play video

  • The biggest kidney stone on record weighed more than a kilogram

  • and was 17 centimeters in diameter.

  • The patient didn't actually swallow a stone the size of a coconut.

  • Kidney stones form inside the body,

  • but unfortunately, they're extremely painful to get out.

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

  • ureters,

  • bladder,

  • or urethra.

  • Urine contains compounds that consist of calcium,

  • sodium,

  • potassium,

  • oxalate,

  • uric acid,

  • and phosphate.

  • If the levels of these particles get too high,

  • or if urine becomes too acidic or basic,

  • the particles can clump together and crystallize.

  • Unless the problem is addressed,

  • the crystals will gradually grow over a few weeks, months, or even years,

  • forming a detectable stone.

  • Calcium oxalate is the most common type of crystal to form this way,

  • and accounts for about 80% of kidney stones.

  • Less common kidney stones are made of calcium phosphate, or uric acid.

  • A slightly different type of stone

  • made of the minerals magnesium ammonium phosphate, or struvite,

  • can be caused by bacterial infection.

  • And even rarer stones can result from genetic disorders

  • or certain medications.

  • A kidney stone can go undetected until it starts to move.

  • When a stone travels through the kidney and into the ureter,

  • its sharp edges scratch the walls of the urinary tract.

  • Nerve endings embedded in this tissue transmit excruciating pain signals

  • through the nervous system.

  • And the scratches can send blood flowing into the urine.

  • This can be accompanied by symptoms of nausea,

  • vomiting,

  • and a burning sensation while urinating.

  • If a stone gets big enough to actually block the flow of urine,

  • it can create an infection, or back flow,

  • and damage the kidneys themselves.

  • But most kidney stones don't become this serious,

  • or even require invasive treatment.

  • Masses less than five millimeters in diameter

  • will usually pass out of the body on their own.

  • A doctor will often simply recommend drinking large amounts of water

  • to help speed the process along,

  • and maybe taking some pain killers.

  • If the stone is slightly larger,

  • medications like alpha blockers can help by relaxing the muscles in the ureter

  • and making it easier for the stone to get through.

  • Another medication called potassium citrate

  • can help dissolve the stones by creating a less acidic urine.

  • For medium-sized stones up to about ten millimeters,

  • one option is pulverizing them with soundwaves.

  • Extracorporeal shock wave lithotripsy uses high-intensity pulses

  • of focused ultrasonic energy aimed directly at the stone.

  • The pulses create vibrations inside the stone itself

  • and small bubbles jostle it.

  • These combined forces crush the stone into smaller pieces

  • that can pass out of the body more easily.

  • But zapping a stone with sound doesn't work as well

  • if it's simply too big.

  • So sometimes, more invasive treatments are necessary.

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

  • Optical fibers can deliver laser pulses to break up the stone.

  • Stones can also be surgically removed through an incision

  • in the patient's back or groin.

  • What about just avoiding kidney stones in the first place?

  • For people prone to them,

  • their doctor may recommend drinking plenty of water,

  • which dilutes the calcium oxalate and other compounds

  • that eventually build up into painful stones.

  • Foods like potato chips,

  • spinach,

  • rhubarb,

  • and beets are high in oxalate,

  • so doctors might advise limiting them.

  • Even though calcium is often found in stones,

  • calcium in foods and beverages can actually help

  • by binding to oxalate in the digestive tract

  • before it can be absorbed and reach the kidneys.

  • If you do end up with a kidney stone, you're not alone.

  • Data suggests that rates are rising,

  • but that world record probably won't be broken any time soon.

The biggest kidney stone on record weighed more than a kilogram

Subtitles and vocabulary

Click the word to look it up Click the word to find further inforamtion about it

B2 US TED-Ed stone kidney calcium urine phosphate

【TED-Ed】What causes kidney stones? - Arash Shadman

  • 10094 1254
    Aming Chiang posted on 2017/07/06
Video vocabulary