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Kidney Stones 101

Kidney stones and ruler

Mind-numbing, excruciating pain. Anyone who's ever had a kidney stone will tell you there's nothing else like it. Sometimes a patient will have a single stone and never have a recurrence. Other times, patients will have kidneys full of stones, or stone after stone. "Based on recent survey data, kidney stones affect about 1 in 12 adults," said Robert Yenchek, MD, MSc, a nephrologist with University of Utah Health.

Kidney stones are a common health concern. Here's what you need to know about these tiny, painful deposits.

What They Are

"Kidney stones, also called nephrolithiasis or urolithiasis, are solid crystals that form and grow in the urinary system under the right conditions," Yenchek said. "They can grow to be various sizes and can differ in chemical composition, with calcium-based kidney stones being the most common."

In adults, kidney stones sometimes pass through the urinary tract on their own, without any complications. But sometimes the stone is too large and will impair urine flow, leading to pain, infection, and blood in the urine. It may also impact kidney function. If they're small enough, kidney stones aren't a big concern, or even painful. Unfortunately, larger stones can cause serious health complications.


Once you've had a painful kidney stone, you'll probably never mistake the symptoms again. These symptoms can include the following:

  • Mild to severe pain in the low back and/or side
  • Pain that occurs in waves
  • Painful urination
  • Blood in the urine
  • Passing gravel or a stone in the urine

Not everyone experiences all the symptoms of a kidney stone; unfortunately, the most common symptom is extreme pain.


Several factors contribute to the formation of kidney stones, which form because of an imbalance in urine chemistry. "The kidneys' job is to process the blood to rid it of waste products and rebalance the body's water and electrolytes," Yenchek said. "It does this by producing urine, which is ideally composed of that which the body doesn't need. Urine can sometimes be relatively concentrated compared to the blood, which can favor crystal formation and growth."

Some of the proteins, electrolytes, and molecules in the urine promote the formation of kidney stones, while others inhibit formation. The balance between promotion and inhibition depends on a person's genetics, diet, medications, medical conditions, anatomy as well as environmental factors. In most cases, no one thing causes kidney stones; instead, it's a combination of factors.


The treatment for a kidney stone varies depending on the size of the stone and how it's affecting the patient. Doctors will prescribe pain control and medication to relax the urinary tract when a patient is passing a kidney stone. They also will monitor the patient closely. But some cases may require surgical intervention or another procedure. Those instances include when a kidney stone doesn't pass on its own, if the patient is in severe pain, if it causes an infection, or if it affects kidney function. Some patients only need medication to pass a kidney stone while others require more medical intervention.


The cause of a patient's kidney stone will determine the ways to prevent additional stones from forming. Doctors will review a patient's unique risk factors, type of stone, stone burden, associated medical conditions, medications, and environmental factors. Doctors will examine a patient's diet, and in many cases conduct a 24-hour urine collection to evaluate urine chemistry. In some cases, doctors will prescribe dietary therapy, but other patients may also require medication. A kidney stone may indicate other health issues such as bone disease, so a doctor may consider additional screening. But maintaining adequate hydration is an integral part of preventing kidney stones. Doctors will determine causes of kidney stones, then prescribe a plan to stop future stone formation.