David S. Goldfarb, MD is a professor of medicine at New York University Grossman School of Medicine. He is chief of nephrology at New York Harbor VA Medical Center and the co-founder of Moonstone Nutrition.
It’s summertime, the season of peak sunshine and warmth, and, for most of us, that’s a good thing. For an unfortunate and growing few, though, summer is the peak season for a condition that can cause excruciating pain: kidney stones.
Kidney stones, made from chemicals in urine, tend to make their presence known in the warmest months of the year. One likely reason is that people sweat more, don’t drink enough to make up for it, and end up with more concentrated urine, allowing crystals to form and grow into stones. In places where it’s fairly warm year-round, such as the southern United States, kidney stones are more common than in colder climes.
Around the world, the incidence of kidney stones is rising. In the United States, the lifetime risk of having at least one kidney stone is now about 10 percent, up from 3.8 percent in the 1970s, according to the National Kidney Foundation. Among possible reasons: the warming climate and the migration of people to warmer urban areas. But heat isn’t the whole story. The way we eat and drink and the rise of obesity and diabetes likely play roles, too.
Typical stones may be as small as a grain of sand or as large as a chickpea. More rarely, they can be as large as golf balls. A small stone may sit in your kidney unnoticed for months or years before it gets big enough or starts moving enough to cause trouble. Often, that happens when a stone moves from a kidney to a ureter, one of the tubes leading to the bladder. The stone may get stuck there, blocking urine flow or causing irritation as it makes its way through the ureter and bladder and out through the urethra. Once a stone becomes problematic, symptoms can start suddenly:
If you show up in an emergency room or doctor’s office with a possible kidney stone, expect to get a CT scan, an ultrasound, or an x-ray to confirm the stone as well as its size and location. You also will get blood and urine tests to check for kidney function, levels of stone-forming substances, and infection.
Unless the stone is quite large or causing unmanageable pain or other complications, your doctor is likely to send you home to see if the stone will pass, which will happen within a few weeks in 80 percent of cases in which stones are no larger than 4 millimeters. Larger stones are less likely to pass. While some people will need prescription painkillers to get through the process, others will do fine with an over-the-counter anti-inflammatory painkiller. Naproxen sodium (Aleve) is a good choice. Anything that helps you relax, even a warm bath, can help. You may also get medication to relax the ureter or change the acidity of your urine.
Contrary to popular belief, studies have not found that drinking extra fluids after a stone forms helps it to pass, though extra fluids can help prevent future stones.
When stones appear unlikely to pass unaided or are causing complications, the next step is a procedure to remove or destroy them. There are several options:
Anyone who’s ever suffered through a kidney stone shares one fervent wish: They never want to do it again. Yet, half will develop another stone within a few years. Those who’ve had two or more stones are at even higher risk. One reassuring fact: Most kidney stones can be prevented, no matter the season. See below to learn how.
Not all kidney stones have the same causes. Knowing which type you’re prone too can help you tailor your prevention plan.