12 Facts About Kidney Stones

Illustration by Mental Floss. Images: iStock
Illustration by Mental Floss. Images: iStock

Kidney stones are more common than ever. According to Harvard Medical School, every year more than 3 million people see a doctor for relief from these hard mineral and salt deposits, which form in your kidney when urine becomes too concentrated. Here's what we know about the condition formally called nephrolithiasis.

1. KIDNEY STONES TYPICALLY CAUSE REALLY PAINFUL SYMPTOMS.

At first you may notice your urine is cloudy, bloody, and foul smelling. Your back may begin to ache, and nausea may come over you. Then, as the stone moves from your kidney into your urinary tract or bladder, sometimes becoming trapped, there’s often an intense, stabbing pain that many people say they wouldn’t wish on their worst enemy.

2. MOST PEOPLE DEVELOP ONE TYPE OF STONE …

What kind of kidney stone you get depends on your diet, fluid intake, genetics, hereditary disorders, and even whether you take certain medications, but the vast majority of people get calcium oxalate stones. They're formed from a mix of calcium in urine and the compound oxalate, which is found naturally in food like nuts, chocolate, and some vegetables, including beets and spinach; oxalate is also produced by your liver. There's some evidence that people who take the seizure medicine topiramate can develop these stones in the form of calcium phosphate.

3. … BUT THERE ARE THREE OTHER KINDS TOO.

Struvite stones are fast-growing mineral deposits that typically develop in response to a urinary tract infection, and can grow large enough to block the kidney, ureter, or bladder before you notice any symptoms; they affect women more than men. Uric acid stones turn up in people who eat a lot of red meat, shellfish, and organ meats, which contain hefty doses of an organic compound called purine that can lead to more uric acid than the kidneys can excrete. Cystine stones are caused by a rare hereditary disorder called cistinuria in which your kidneys excrete excessive amounts of the amino acid cystine.

4. THEY'RE EXTREMELY COMMON—ESPECIALLY IN MEN.

There's a solid chance you could end up with a kidney stone. The National Kidney Foundation notes that one in 10 people will develop one during the course of their life. And if you’re male, take note: Your gender alone is considered a kidney stone risk factor. Men are twice as likely as women to develop them. Another factor is age: Although stones are most common from ages 20 through 50, they tend to peak around age 30.

5. IF YOU’VE HAD A KIDNEY STONE, YOU’LL PROBABLY DEVELOP ANOTHER ONE …

Sorry to say, but simply having a kidney stone puts you at risk for a recurrence. If you’ve had one, the U.S. National Library of Medicine notes that there’s a 30 to 50 percent chance more stones will form within five years.

6. … BUT YOU CAN TAKE STEPS TO PREVENT THEM.

Cutting back on sodium (i.e. deli meats, packaged soups, and processed foods) can help, because a stone can form from excessive salt consumption. You should also avoid too much animal protein—it produces urine containing more acid, which is known to increase your risk for kidney stones—and increase your intake of fruits, vegetables, whole grains, and low-fat dairy. And be sure to drink plenty of fluids, especially water—at least 12 glasses a day. (That's good advice for everyone, not just those prone to kidney stones.)

Don't drink much apple or cranberry juice as both contain oxalates and are linked to an increased risk of developing calcium oxalate stones. High doses of Vitamin C may boost the concentration of oxalate in urine; the Cleveland Clinic recommends a daily maximum of 500 milligrams.

7. IT'S A MYTH THAT CALCIUM CREATES SOME KIDNEY STONES.

Despite the fact that the word calcium is part of the most common kind of kidney stone, you don’t need to treat calcium as the enemy. In fact, having too little calcium can actually increase the odds you’ll get these types of stones. According to the Cleveland Clinic, eating about two or three servings of calcium-rich foods daily reduces oxalate absorption, helping to keep calcium oxalate stones away. So get out the cheese.

8. IF YOU PASS A STONE, CONGRATULATIONS! NOW TAKE IT TO A DOCTOR.

Ninety percent of kidney stones are passed through urination. Getting one out this way may hurt a lot, but once the stone has finished causing you agony, it could provide clues that could help you avoid developing another one. If you’re able to retrieve the stone, bring it to your doctor, who can order an analysis. Identifying its components can reveal the kind of stone it is and potentially point to a treatment or prevention plan.

9. IF YOU CAN’T PASS A STONE, TREATMENTS ARE AVAILABLE …

In an attempt to exit the body, a stone travels from the kidney to the bladder through a narrow tube called the ureter. If the stone is larger than a quarter-inch, it's simply too big to pass through the ureter, and will get trapped there. (If it can make it through to your bladder, it's small enough to pass out out of your body through the urethra.) This causes intense pain, blocked urine flow, and possible bleeding from urinary tract walls. That's when it's time for treatment.

There are several methods for getting rid of a kidney stone, all of which aim to break the stone into smaller pieces so they can leave the body. In an extracorporeal shock wave lithotripsy (from the Greek for "crushed stone"), high-frequency sound waves are applied externally to break stones up, allowing them to pass when you pee. Laser lithotripsy takes a similar approach: Stones in the ureter are broken up with a laser and also leave the body naturally. More invasive is percutaneous ultrasonic lithotripsy, which involves passing narrow instruments (including a fiberoptic camera) through your back to your kidney; ultrasound breaks the stones up, and then fragments are removed by an instrument. Finally, a ureteroscopy is a treatment option in which a small scope is inserted in the ureter towards the bladder to determine the stone's location. Then it's broken up for natural passage or removed altogether. Luckily, you're unconscious under general anesthesia during the last procedure.

10. … AND THEY'RE FAR SUPERIOR TO THOSE USED IN THE PAST.

Kidney stones are nothing new—mentions of the painful formations go back more than 5000 years, to Mesopotamian medical texts—and medical interventions have occurred for just as long. Stones made it into the Hippocratic Oath, in which physicians swore they would "not use the knife, not even on sufferers from stone," leaving the procedure to "such men as are engaged in this work" [PDF]. Surgeons in ancient Greece and India were attempting stone removal as far back as the 7th century BCE.

The 16th to 18th centuries were a heyday for stone surgeons, who were largely self-taught. The most notorious of them was Frere Jacques Beaulieu. He pioneered the lateral perineal lithotomy—which involved making an incision in the perineum, inserting a terrifying cutting instrument into the bladder, cutting up the stone, and then extracting the pieces with the instrument or his fingers—in the late 17th century. Unfortunately for his patients, he had no technical training, and his method was often deadly; in 1698, after 25 of his 60 patients died, he was banned from doing the procedure—but he didn't stop. He's thought to have performed more than 5000 lithotomies. (And no, the song doesn't seem to be about him.)

11. IF ALL ELSE FAILS, TRY RIDING A ROLLER COASTER.

If you’re a thrill seeker who happens to have kidney stones (and some vacation time), you may be in luck. After a "notable number" of patients reported that riding the Big Thunder Mountain roller coaster at Walt Disney World in Orlando helped them to pass their kidney stones, Michigan State University urologist David Wartinger decided to investigate. He created a kidney replica—complete with kidney stones—put it in a backpack, and let it ride the roller coaster 60 times. It worked—but passing the stones depended on where the backpack was placed in the coaster. Rides in the last car were the most effective, with the stones passing 64 percent of the time, while the front few cars yielded only a 16 percent success rate.

Big Thunder Mountain was the only ride in the theme park that was effective. Neither Space Mountain nor Aerosmith's Rock 'n' Roller Coaster did the trick, likely because they were too fast, with a G-force that pinned the stones in place. Of course, while this is an interesting finding, if you suspect you have kidney stones, speak to your doctor before you high-tail it to Walt Disney World.

12. A KIDNEY STONE THE SIZE OF A MOUSE WAS REMOVED FROM A MAN IN 2004.

The stone measured 5.11 inches at its widest point—a world record. Five years later, a whopping 2.5-pound stone was surgically removed from a man in Hungary in 2009. Perhaps seeing a bunch of kidney stones in one place other than originating from your own body will put you at ease. If that’s the case, check out the International Museum of Surgical Science in Chicago, where a collection of stones is on display in glass jars.

A Custom Wheelchair Allowed This Brain-Injured Baby Raccoon to Walk Again

фотограф/iStock via Getty Images
фотограф/iStock via Getty Images

Animal prosthetics and wheelchairs allow dogs, cats, and even zoo animals with limited mobility to walk again, but wild animals with disabilities aren't usually as lucky. Vittles, a baby raccoon rescued in Arkansas, is the rare example of an animal that was severely injured in its natural habitat getting a second shot at life.

As Tribune Media Wire reports, Vittles came to wildlife rehab specialist Susan Curtis, who works closely with raccoons for the state of Arkansas, with a traumatic brain injury at just 8 weeks old. The cause of the trauma wasn't clear, but it was obvious that the raccoon wouldn't be able to survive on her own if returned to the wild.

Curtis partnered with the pet mobility gear company Walkin' Pets to get Vittles back on her feet. They built her a tiny custom wheelchair to give her balance and support as she learned to get around on her own. The video below shows Vittles using her legs and navigating spaces with help from the chair and guidance from her caretaker.

Vittles will likely never recover fully, but now that she's able to exercise her leg muscles, her chance at one day moving around independently is greater than it would have been otherwise. She now lives with her caretaker Susan and a 10-year old raccoon with cerebral palsy named Beetlejuice. After she's rehabilitated, the plan is to one day make her part of Arkansas's educational wildlife program.

[h/t Tribune Media Wire]

Why You Should Never Shower With Your Contact Lenses In

belchonock/iStock via Getty Images
belchonock/iStock via Getty Images

Contact lenses offer a level of convenience for those with less-than-perfect vision that glasses can hardly compete with, but that doesn’t mean the daily struggle of taking them in and out of your eyes doesn’t wear on you. If you get a little lazy and decide it’s fine to leave them in your eyes during showers or pool parties, think again.

According to Popular Science, a 41-year-old woman in the UK lost sight in her left eye as a result of frequently showering and swimming without removing her contacts. The culprit was Acanthamoeba polyphaga, a protozoa that crawled into her eye and caused a cornea infection called Acanthamoeba keratitis. After two months of pain, blurry vision, and light sensitivity, the woman sought medical attention at the Manchester Royal Eye Hospital, where doctors discovered a ring shape in her left eye and a hazy layer covering her cornea. Upon testing her vision, they found that her left eye was now 20/200, which counts as legally blind in the United States.

Leela Raju, an ophthalmologist and cornea specialist at New York University, told Popular Science that the single-celled organisms “can be anywhere,” including pools, hot tubs, showers, dirty saline solution containers, and even tap water. Lens-wearers make up around 85 percent of those who get infected, and experts think it may be because the amoeba can latch onto a contact lens more easily than a bare eye.

Though Popular Science reports that Acanthamoeba keratitis only affects one or two people out of every million contact wearers each year, that’s no reason not to be careful. If you do catch it, you’ll likely need a cornea transplant, and even that won’t necessarily restore your eyesight to its previous state—after her transplant, the UK woman’s left eye now has 20/80 vision.

“It’s just a long road, for something that’s totally preventable,” Raju says. In addition to removing your contacts before swimming, showering, or sleeping, you should also refrain from reusing saline solution, make sure your contact case is completely clean and dry before filling it with more solution, and check out these other tips.

[h/t Popular Science]

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