What You Need to Know About Kidney Stones

When a kidney stone strikes, the pain can be intense. Ojas Shah, MD, chair of the Department of Urology at Columbia, explains how to recognize a kidney stone, how they're treated, and what you can do to help prevent them.

What is a kidney stone?

Kidney stones are hard, rock-like pieces of material that form in one or both of your kidneys. This happens when high levels of certain minerals, which form crystals, are in your urine. Kidney stones are common—about 8% of the U.S. population develops them—and they can affect men, women, and children.

What are the symptoms of kidney stones?

Kidney stone pain can be extremely severe; we sometimes compare it to the pain of natural childbirth. Typically, patients have pain in their flank that can radiate toward the groin or pelvis as the stone moves toward the bladder.

Nausea, vomiting, blood in the urine, and burning with urination can also occur.

When should someone seek medical attention?

Fever, severe pain, or persistent nausea and vomiting are all signs it's time to get medical care. These symptoms could require an emergency room visit, hospitalization, or treatment to manage the stone and symptoms. Fever is especially concerning because it can signal an infection.

Will a kidney stone pass on its own?

Smaller stones often can pass on their own, and medications may help. But a larger stone that becomes stuck, or a large stone in the kidney, will likely require some kind of intervention.

How are kidney stones treated?

There are three main treatment options, including:

Ureteroscopy: Probably the most common procedure we perform today, this approach uses a small scope and lasers to break up and remove stones without an incision.

Shockwave lithotripsy: This technique uses sound waves from outside the body to break a stone into smaller pieces so they can spontaneously pass.

Percutaneous nephrolithotomy: Intended for larger or complex stones, this procedure involves making a small opening into the kidney to break up and remove the stones.

Can diet help prevent kidney stones?

Absolutely. Although people with a family history are more prone to developing stones, fluid intake and diet are also important. High-animal-protein diets and excessive salt can contribute to stone formation.

Even some foods that are considered "healthy"—including spinach, beets, rhubarb, sweet potatoes, nuts, and tofu—need to be moderated in people prone to stones because they are high in oxalate, which can contribute to stone formation.

Interestingly, dietary calcium can make you less prone to stones, while calcium supplements and products such as antacids (made with calcium) can sometimes increase the risk. We generally recommend getting one's calcium from food and limiting calcium supplements, unless they're necessary.